Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| lipopigments in the brushtail possum, trichosurus vulpecula. | two lipopigments have been found in the hepatic and lymphoid tissues of the brushtail possum, trichosurus vulpecula. one pigment was present in hepatocytes of five out of 15 (33%) possums from a site in the wairarapa region in the north island of new zealand, but was absent from the livers of 34 possums from a site in the manawatu. the pigment is possibly of dietary origin. an extra-hepatic lipopigment was found within macrophages in the lymph nodes of three out of 12 (25%) possums from the wair ... | 1994 | 16031749 |
| effects of cholinergic stimulation and aldosterone administration on salivary parotid secretion in the brushtail possum, trichosurus vulpecula. | parotid salivation was stimulated by infusion of bethanechol chloride into anaesthetized brushtail possums to ascertain maximal flow rates, salivary composition and dietary adaptations of salivary function. secretion rates for one gland ranged from 5.3 +/- 0.16 to 84.3 +/- 3.20 microliters/min (2.4 +/- 0.07 to 37.8 +/- 1.43 microliters/min per kg body weight). salivary osmolality (160.8 +/- 15.39 to 248.2 +/- 8.70 mosmol/kg) and the concentrations of na (63.1 +/- 10.93 to 124.1 +/- 5.52 mmol/l) ... | 1994 | 8024500 |
| mesotocin and arginine-vasopressin in the corpus luteum of an australian marsupial, the brushtail possum (trichosurus vulpecula). | the neuropeptide hormones arginine-vasopressin (avp) and oxytocin (ot) have been found in the ovarian follicles and corpora lutea (cl) of many eutherian mammals. in ruminants, there is persuasive evidence that luteal ot is involved in luteolysis via stimulation of uterine prostaglandins. however, based on scant evidence, the marsupial ovary has been viewed as being devoid of ot-like and avp-like peptides. in this study, corpora lutea from the brushtail possum were examined for ot, avp, and mesot ... | 1994 | 8174926 |
| nitric oxide mediates nonadrenergic, noncholinergic neural relaxation in the australian possum. | nitric oxide has been shown to play an important role in neurally mediated relaxations of gastrointestinal smooth muscle. the aim of this study was to determine whether no may be the inhibitory transmitter to circular smooth muscle from the sphincter of oddi of the australian brush-tailed possum (trichosurus vulpecula). | 1993 | 7902822 |
| smi cortical barrels in an australian marsupial, trichosurus vulpecula (brush-tailed possum): structural organization, patterned distribution, and somatotopic relationships. | this study reports on the cerebral cortex of an australian marsupial, trichosurus vulpecula (brush-tailed possum). it consists of an analysis of layer iv of somatosensory cortex in tangential sections of flattened specimens and in oblique radial sections stained to show nissl substance or myelin, or tested for succinic dehydrogenase. it includes results of electrophysiological mapping experiments that ascertained the somatotopic significance of the cytoarchitecture of this cortical region. layer ... | 1993 | 8282853 |
| posterior pituitary of the newborn marsupial possum, trichosurus vulpecula. | the fetal anterior pituitary-adrenal axis is thought to be involved in the initiation of birth in both eutherian and marsupial mammals. little is known about the structure and function of the posterior pituitary at birth in the marsupial. immunocytochemistry, high pressure liquid chromatography, and radioimmunoassay were used to identify vasopressin and mesotocin in the posterior pituitary of a newborn marsupial, the brushtail possum, trichosurus vulpecula. the concentrations of vasopressin and ... | 1993 | 8238974 |
| the development of thermoregulation in the marsupial brushtail possum trichosurus vulpecula. | 1. the adult possums showed a circadian rhythm of body temperature with a peak in temperature around midnight and a nadir at noon. 2. the young possum within the pouch displayed a circadian rhythm with the highest temperatures during the day and the lowest in the early evening. 3. although the body temperature of the young possum exceeded that of the mother occassionally, for the major part of the 24 hr the body temperature of the young was lower than that of the mother. 4. the young possum coul ... | 1993 | 7902793 |
| effect of photoperiod on the breeding season of the marsupial possum trichosurus vulpecula. | the production of young by three groups of eight possums, housed in a natural, a short-day (10 h light:14 h dark) and a long-day (14 h light:10 h dark) photoperiod was monitored for 24 months to determine the role of photoperiod on the occurrence and duration of the breeding season. possums were housed in each of the three light regimens on 22 november. the possum has a gestation duration of 17.5 days. removal of the newborn young leads to ovulation approximately 9 days later and birth 26 days l ... | 1993 | 8410819 |
| effects of halothane anesthesia on the motility of the sphincter of oddi and transsphincteric flow in australian brush-tailed possums. | we evaluated the effect of halothane anesthesia on the motility of the sphincter of oddi and simultaneous transsphincteric flow in australian brush-tailed possums (trichosurus vulpecula). halothane levels in the range of 0.25 to 2% were administered and decreased transsphincteric flow in a dose-dependent manner. sphincter of oddi basal pressure was higher than normal, but not in a dose-dependent manner. additionally, halothane anesthesia influenced the sphincter of oddi motility by decreasing th ... | 1993 | 8355483 |
| inhibition of cardiac vagal action by galanin but not neuropeptide y in the brush-tailed possum trichosurus vulpecula. | 1. stimulation of the right cardiac sympathetic nerve for 2 min at 16 hz in the presence of either beta- or alpha- and beta-adrenoceptor blockade evoked attenuation of cardiac vagal action in eight possums: 31.3 +/- 10.3% maximum inhibition of cardiac vagal action on prolonging pulse interval, with a time to half-recovery of 4.9 +/- 1.1 min. 2. intravenous injection of galanin (2-3.5 nmol kg-1) evoked similar inhibition of cardiac vagal action: 41.3 +/- 4.1% maximum inhibition of cardiac vagal a ... | 1993 | 7688807 |
| structure and innervation of the extrahepatic biliary system in the australian possum, trichosurus vulpecula. | the morphology, microanatomy and innervation of the biliary tree of the australian possum, trichosurus vulpecula, was examined. the gross morphology of the gallbladder, hepatic and cystic ducts, and the course of the common bile duct, conforms to those of other species. the sphincter of oddi has an extraduodenal segment that extends 15mm from the duodenal wall; within this segment the pancreatic and common bile ducts are ensheathed together by sphincter muscle. their lumens unite to form a commo ... | 1993 | 8268104 |
| the unique stability of the marsupial sperm acrosomal membranes examined by unprotected freeze-thawing and treatment with the detergent triton x-100. | in this study of the unique stability of the marsupial acrosome, experiments were carried out on the acrosomes of spermatozoa of the tammar wallaby (macropus eugenii), common brushtail possum (trichosurus vulpecula) and grey short-tailed opossum (monodelphis domestica). light microscopy showed that 4% of opossum and 15% of possum and wallaby spermatozoa lost their acrosomes after freeze-thawing. electron microscopy revealed that freeze-thawing also induced changes in the acrosomal matrix of some ... | 1993 | 8234885 |
| differentiation of the gonads and initiation of mammary gland and scrotum development in the brushtail possum trichosurus vulpecula (marsupialia). | the first appearance of the mammary and scrotal primordia and the sexual differentiation of the gonads of the brushtail possum, trichosurus vulpecula, are described. primordial germ cells were first observed, in fetuses of 7.5 mm crown-rump length, in the gonadal ridges and migrating up the dorsal mesentery. mammary primordia were first observed in fetuses of 11 mm, and scrotal primordia in those of 12 mm crown-rump length. these structures were diagnostic of female and male brushtail possums re ... | 1993 | 8342793 |
| role of diacylglycerols and calcium in the marsupial acrosome reaction. | acrosomal loss was induced in marsupial spermatozoa by an intermediate of the phosphoinositide pathway. the diacylglycerol, 1,2-dioctanoyl-sn-glycerol (dic8; 100 mumol l-1) induced acrosomal loss in 70% of brushtail possum (trichosurus vulpecula) spermatozoa and in 80% of tammar wallaby (macropus eugenii) spermatozoa. the dic8-induced acrosomal loss was not enhanced by co-incubation with calcium ionophore a23187 and occurred in ca(2+)-free medium and in the presence of the calcium chelator egta ... | 1993 | 8107018 |
| adiaspiromycosis in suspected cases of pulmonary tuberculosis in the common brushtail possum (trichosurus vulpecula). | pulmonary adiaspiromycosis was diagnosed in 15 of 17 common brushtail possums (trichosurus vulpecula) examined for bovine tuberculosis. emmonsia crescens was isolated from two of the affected animals. this is the first reported isolation of this dimorphic fungus in new zealand. the infections varied from light to heavy with sparsely distributed, focal, 1-2 mm diameter, grey-white spherical granulomas in the lightly infected cases to innumerable foci throughout the lungs in the heavily infected c ... | 1993 | 16031725 |
| traumatic injuries occurring in possums and gliders in the blue mountains, new south wales. | twenty common brushtail possums (trichosurus vulpecula), 23 ringtail possums (pseudocheirus peregrinus) and five sugar gliders (petaurus breviceps) from the blue mountains, new south wales, australia were evaluated for traumatic injuries between 1989 and 1990. ten brushtail possums and five ringtail possums were hit by motor vehicles with injuries primarily to the anterior of the body. fifteen ringtail possums and all sugar gliders were attacked by cats. four brushtail possums were attacked by d ... | 1993 | 8258866 |
| a light-microscopic immunocytochemical study of the endocrine pancreas in the australian fat-tailed dunnart (sminthopsis crassicaudata). | the endocrine pancreas of the australian fat-tailed dunnart (sminthopsis crassicaudata) was investigated by means of immunocytochemistry using the avidin-biotin-peroxidase technique. this was a light microscopic study using this established technique and has not been previously investigated. serial paraffin sections were stained individually with primary antibodies for anti-porcine glucagon, anti-beef pork insulin, anti-human somatostatin, and anti-avian pancreatic polypeptide (app), anti-bovine ... | 1992 | 1352914 |
| evidence that cortical granule formation is a periovulatory event in marsupials. | formation of cortical granules was examined in superovulated oocytes from three marsupial species, brushtail possums (trichosurus vulpecula) tammar wallabies (macropus eugeniii) and grey short-tailed opossums (monodelphis domestica) and in oocytes obtained during natural cycles in macropus eugenii. superovulation was induced by pregnant mares' serum gonadotrophin/gonadotrophin-releasing hormone (pmsg/gnrh) protocols and natural ovulation by removal of pouch young. oocytes were collected after ov ... | 1992 | 1404089 |
| mapping human x-linked genes in the phalangerid marsupial trichosurus vulpecula. | we mapped 15 human x-chromosome markers in the common brush-tailed possum, trichosurus vulpecula (kerr), which represents the australian marsupial family phalangeridae. in situ hybridization was used to localize highly conserved human x-linked genes to chromosomes of t. vulpecula diploid lines. ten genes located on the long arm of the human x (human xq genes) all mapped to the possum x chromosome. however, all five genes located on the short arm of the human x (human xp genes) mapped to autosome ... | 1992 | 1427847 |
| biphasic retinal neurogenesis in the brush-tailed possum, trichosurus vulpecula: further evidence for the mechanisms involved in formation of ganglion cell density gradients. | we investigated cell generation in the retina of the brush-tailed possum (trichosurus vulpecula) by using tritiated (3h)-thymidine labelling of newly generated cells. animals aged between postnatal day (p) 5 and 85 each received a single injection of 3h-thymidine. following autoradiographic processing, maps of labelled cells were constructed from retinal sections. retinal cell generation takes place in two phases, the first is concluding in the retinal periphery at p53 as the second is seen to c ... | 1992 | 1469115 |
| giardia intestinalis in north island possums, house mice and ship rats. | giardia intestinalis cysts were detected in faeces from 12.9% of 124 brushtail possums (trichosurus vulpecula) trapped in auckland, hawke's bay, the wairarapa and wellington; in faecal material from 61.0% of 77 ship rats (rattus rattus) from areas of auckland, hawke's bay and wellington; and in faecal material from 25.3% of 182 house mice (mus musculus) from the north island. possums and rodents in forested areas of auckland and wellington city water catchments were infected. the role of wild an ... | 1992 | 16031653 |
| a light-microscopic immunocytochemical study of the endocrine pancreas in the australian brush-tailed possum (trichosurus vulpecula). | the endocrine pancreas of the australian brush-tailed possum (trichosurus vulpecula) was investigated by means of immunocytochemistry using the avidin-biotin-peroxidase technique. this was a light microscopic study using this established technique. serial paraffin sections were stained individually with primary antibodies for glucagon, insulin, somatostatin, and pancreatic polypeptide (pp), showing the same islet. cells immunoreactive to glucagon, insulin, somatostatin and pp were found in endoc ... | 1992 | 1380858 |
| unexpected oocyte growth after follicular antrum formation in four marsupial species. | during examination of maturing preovulatory marsupial oocytes we noted that oocyte diameters were invariably about 50% greater than the figures reported in earlier histological studies. as all previous investigations were limited to small follicles (at most 25% the size of the ovulating follicle), the present study was initiated to examine oocyte growth during the whole period of follicular development. oocyte and follicle diameters were measured for three australian (trichosurus vulpecula, macr ... | 1992 | 1339855 |
| the transfer of thyroxine from the mother to the young of the marsupials, the bandicoot (isoodon macrourus) and the possum (trichosurus vulpecula). | 1. the young of the bandicoot and possum are of similar weight at birth (200-250 mg) but by day 50 post-partum have weights of 100 and 20 g, respectively. the aim of this study was to determine whether the disparate growth rate was associated with a difference in the transfer of thyroxine from mother to young. 2. radioactive thyroxine was injected intramuscularly into the lactating female and 24 hr later a blood sample was obtained from the mother and the pouch young removed. the amount of radio ... | 1992 | 1358508 |
| influence of stress of capture on haematological values and cellular immune responses in the australian brushtail possum (trichosurus vulpecula). | possums (trichosurus vulpecula) captured for the first time (single-capture) had significantly lower blood lymphocyte and eosinophil counts, but higher neutrophil counts than possums which had been captured frequently. single-capture possums also had depressed lymphocyte responses to concanavalin a (males and females) and pokeweed mitogen (males only). the haematological changes and the depressed lymphocyte reactivity to the t-cell mitogens were consistent with the animals being in a stressed st ... | 1992 | 16031681 |
| erythromycin and motilin stimulate sphincter of oddi motility and inhibit trans-sphincteric flow in the australian possum. | the actions of erythromycin lactobionate and porcine motilin on trans-sphincteric flow and simultaneous sphincter of oddi motility were studied in 15 anaesthetized australian brush-tailed possums (trichosurus vulpecula). erythromycin (25-200 micrograms/kg) and motilin (25-200 ng/kg) were administered as graded doses by close intraarterial injection. trans-sphincteric flow was measured as inflow and outflow. both motilin and erythromycin decreased trans-sphincteric inflow (both p < 0.0001) and ou ... | 1992 | 1484568 |
| brain content and plasma concentrations of arginine vasopressin in an australian marsupial, the brushtail possum trichosurus vulpecula. | arginine vasopressin (avp) has been identified and quantified in the brain and plasma of the possum using a highly specific radioimmunoassay and high-performance liquid chromatography. large amounts of avp were found in the pituitary (16.3 +/- 0.56 micrograms/pituitary, n = 5) and hypothalamus (398 +/- 82.5 ng/hypothalamus), and significant amounts of avp were also present in the cerebral cortex (26.8 +/- 11.5 ng/cortex). plasma avp concentrations were significantly lower (2.2 +/- 0.45 pg/ml, n ... | 1992 | 1478438 |
| the role of photoperiod on the initiation of the breeding season of the brushtail possum (trichosurus vulpecula). | the role of photoperiod on the initiation of the breeding season of brushtail possums was investigated in possums housed in three light regimens: a short-day, a natural and a long-day photoperiod. seven possums were housed in a natural photoperiod. four possums were transferred to a short-day photoperiod (10 h light, 14 h dark) and eight possums to a long-day photoperiod (14 h light, 10 h dark) on 22 november, when the daylength was 13.34 h. the first rises in plasma progesterone concentrations ... | 1992 | 1404087 |
| galanin is more common than npy in vascular sympathetic neurons of the brush-tailed possum. | the distribution of galanin (gal) in sympathetic vascular neurons of adult and juvenile brush-tailed possums (trichosurus vulpecula), was examined using double-labelling immunohistochemistry. this was compared with the distribution of neuropeptide y (npy) in the same tissues. immunoreactivity (ir) to galanin was present in the majority (64-99%) of nerve cell bodies in paravertebral sympathetic ganglia, where it mostly co-existed with ir to the catecholamine-synthesizing enzyme, tyrosine hydroxyl ... | 1992 | 1371612 |
| carcass composition and meat quality of brush-tail possums (trichosurus vulpecula). | one-hundred-and-thirty-nine possums, balanced as far as possible for sex (68 male, 71 female) and age (1 year, 42; 2-4 years, 61; 5+ years, 36), were slaughtered and the dissected carcass composition, muscle, and cooked meat composition measured. possums were slaughtered at time in captivity tic 0 (n = 58), tic 14 days (n = 20) and tic 28 days (n = 61). compared with the 5+ years (mature) age group the 1 year olds (juveniles) were 67% and the 2-4 year olds (immature) 96% of the live weight of th ... | 1992 | 22059633 |
| oxytocin receptors in the mammary gland and reproductive tract of a marsupial, the brushtail possum (trichosurus vulpecula). | previous studies of marsupial lactation have shown that the milk-ejection reflex changes in sensitivity, being greater in small mammary glands sucked by small pouch young and lesser in larger glands supplying milk to larger young. the involvement of oxytocin receptors in these changes was examined in the brushtail possum trichosurus vulpecula. oxytocin receptors were measured in the mammary glands, uterus, and medial vaginal sacs by radioreceptor assay, using [3h]oxytocin as radioligand. in the ... | 1991 | 1661615 |
| bile acids of marsupials. 2. hepatic formation of vulpecholic acid (1 alpha,3 alpha,7 alpha-trihydroxy-5 beta-cholan-24-oic acid) from chenodeoxycholic acid in a marsupial, trichosurus vulpecula (lesson). | free vulpecholic acid (1 alpha,3 alpha,7 alpha-trihydroxy-5 beta-cholan-24-oic) is the major biliary component of the australian opossum (trichosurus vulpecula), accompanied only by a few percent of its taurine conjugate. in order to exclude a microbial involvement in its formation (i.e., secondary origin) four sets of experiments were performed. it was found that a) the level of vulpecholic acid remained unchanged in the bile of opossums fed with neomycin and kanamycin for 7 days prior to bile ... | 1991 | 1753212 |
| spontaneous or experimentally induced formation of a special zone in the adrenal cortex of the adult brush-tailed possum (trichosurus vulpecula). | the cytology and ultrastructure of the hypertrophied special zone, which is formed spontaneously in the adrenal cortex of adult female brush-tailed possums (trichosurus vulpecula), was compared to the adrenocortical tissue in adult males in which the special zone, normally absent, was induced following castration alone or by additional treatment with follicle-stimulating hormone (fsh). the special zone in females was situated between the zona fasciculata and the zona reticularis, the latter bein ... | 1991 | 1901439 |
| retinal epithelial fine structure in the brush-tailed possum (trichosurus vulpecula). | as part of a comparative morphological study, the fine structure of the retinal pigment epithelium (rpe), the choriocapillaris and bruch's membrane (complexus basalis) has been studied by electron microscopy in the brush-tailed possum (trichosurus vulpecula), an australian marsupial. in this species, the rpe consists of a single layer of squamous cells which show numerous shallow basal (scleral) infoldings as well as extensive apical (vitreal) processes enclosing rod outer segments. the epitheli ... | 1991 | 2048742 |
| a simple glycerol-based freezing protocol for the semen of a marsupial trichosurus vulpecula, the common brushtail possum. | frozen storage of semen and embryos is now a well established part of the breeding of many eutherian mammals but it has not been applied to marsupials. this paper reports the first successful technique for the frozen preservation of marsupial spermatozoa. semen was collected by electroejaculation under anaesthesia from a pool of five brushtail possums. the ejaculated semen was diluted 1:1 with krebs henseleit ringer, centrifuged at 800 g for 5 min, resuspended in the test cryoprotectant media at ... | 1991 | 1947217 |
| whey proteins of the common brushtail possum (trichosurus vulpecula): isolation, characterization and changes in concentration in milk during lactation of transferrin, alpha-lactalbumin and serum albumin. | 1. transferrin and serum albumin were purified from both whey and serum and alpha-lactalbumin was purified from whey from the common brushtail possum (trichosurus vulpecula). 2. the n-terminal amino acid sequences for transferrin and serum albumin were identical for the proteins from both whey and serum and showed homologies with transferrin or serum albumin from other species. 3. n- and c-terminal regions of possum alpha-lactalbumin were also sequenced and have been compared with wallaby alpha- ... | 1991 | 1868684 |
| adenovirus precipitating antibodies in the sera of brush-tailed possums in new zealand. | sera collected from the australian brush-tailed possum trichosurus vulpecula in new zealand in 1975 and 1989 were tested for the presence of antibodies to adenovirus. of the 231 sera tested in an agar gel diffusion test, eight (3.5%) had precipitating antibodies to the group specific antigen of mammalian adenoviruses. available data allowed 99/231 sera to be classified as being obtained from either adult (total 62) or sexually immature (total 37) possums. from the adult animals, 4/62 (6.5%) sera ... | 1991 | 16031621 |
| stability of the acrosome of the brush-tailed possum (trichosurus vulpecula) and tammar wallaby (macropus eugenii) in vitro and after exposure to conditions and agents known to cause capacitation or acrosome reaction of eutherian spermatozoa. | ejaculated spermatozoa from brush-tailed possums and tammar wallabies were washed by a 'swim up' procedure into hanks balanced salt solution (hbss), and then exposed to test solutions. spermatozoa were incubated at 33 degrees c, or room temperature when long-term sperm survival (greater than 10 h) was required. exposure of spermatozoa to calcium ionophore a23187, cyclic nucleotides, phosphoinositide pathway intermediates, lysophospholipids, trypsin or 'capacitating' high ionic-strength medium (3 ... | 1991 | 1847424 |
| marsupial possum neurotensin: a unique mammalian regulatory peptide exhibiting structural homology to the avian analogue. | neurotensin has been isolated from small intestinal extracts of an australian marsupial, the brush-tailed possum (trichosurus vulpecula). the primary structure was determined as: pglu-leu-his-val-asn-lys-ala-arg-arg-val-tyr-ile-leu. when compared with bovine neurotensin, marsupial possum neurotensin exhibits four amino acid substitutions. his for tyr3, val for glu4 and ala for pro7 are identical with those found in chicken neurotensin. in addition, substitution of pro10 with val is unique among ... | 1991 | 1924896 |
| uterine oxytocin receptors in an australian marsupial, the brushtail possum, trichosurus vulpecula. | 1. oxytocin receptors in the uterus of the brushtail possum (t. vulpecula) were characterized by radioreceptor assay and compared with those of the sheep and rat uterus. 2. a single oxytocin binding site was found with an affinity (kd) and receptor concentration (ro) of 3.0 +/- 0.8 nmol/l and 200 +/- 60 fmol/mg protein, respectively (sem; n = 5). the receptor was stable at -20 degrees c; divalent ions were required for optimum binding. 3. competitive displacement curves with related peptides sho ... | 1990 | 1968806 |
| digesta retention and fibre digestion in brushtail possums, ringtail possums and rabbits. | 1. mean retention times (mrts) of fluid (marked with co-edta), fine particles (mordanted with yb) and large particles (mordanted with cr) were measured in brushtail possums (trichosurus vulpecula), ringtail possums (pseudocheirus peregrinus) and laboratory rabbits fed semipurified diets. 2. in brushtail possums there were no significant differences in mrt among the three digesta markers. 3. in ringtail possums mrts of the fluid and fine particle markers were approximately twice that of the large ... | 1990 | 1976477 |
| metabolic effects of cortisol, acth, adrenalin and insulin in the marsupial sugar glider, petaurus breviceps. | the effects of cortisol, acth, adrenalin and insulin on indices of carbohydrate, fat and protein metabolism were investigated in the conscious marsupial sugar glider petaurus breviceps. short-term i.v. infusion of cortisol at dose rates of 0.02, 0.2 and 1.0 mg/kg per h caused the plasma glucose concentration to rise sharply from the normal range of 3.3-4.4 to 8.1-8.7 mmol/l at the end of the infusion period without significant alteration in plasma free fatty acid (ffa), amino acid or urea concen ... | 1990 | 2174452 |
| an immunohistochemical study of endocrine cells in the proximal duodenum of eight marsupial species. | the proximal duodenum of eight marsupial species, (koala, common brushtail possum, ring-tailed possum, common wombat, great grey kangaroo, parma wallaby, short-nosed bandicoot and tiger cat) were investigated immunohistochemically using 12 specific antisera for gut hormones. several types of immunoreactive cells were seen on the intestinal villi and in crypts of these species: 9 types in the koala; 8 types in the common brushtail possum; 7 types in the common wombat; 6 types in the short-nosed b ... | 1990 | 2182587 |
| angiotensin receptors in an australian marsupial, the brushtail possum trichosurus vulpecula. | in this study, the binding properties of angiotensin receptors were examined in the liver, adrenal, brain, and vascular tissue of the brushtail possum, trichosurus vulpecula. with 125i-ile5-angiotensin ii as the radioligand, the binding affinity (ka) and receptor number (r0) were estimated for the liver (ka = 3.60 +/- 0.31 liters/nmol; r0 = 23.8 +/- 1.30 pmol/g tissue; n = 8) and adrenal (ka = 1.68 +/- 0.29 liters/nmol; r0 = 1.67 +/- 0.23 pmol/g tissue; n = 8). specific binding was not found in ... | 1990 | 2295416 |
| vascular and avascular retinae in mammals. a funduscopic and fluorescein angiographic study. | intraretinal blood vessels are present in some and absent in other vertebrate species, including the mammals. among the marsupials, both vascular and avascular retinae are seen. we determined the funduscopic appearance of the eye, investigated the functional aspects of ocular blood flow in both types of retina in marsupials and compared our results with known patterns in placental mammals. the australian polyprotodont marsupials, the tasmanian devil, sarcophilus harrisii, and the quoll, dasyurus ... | 1990 | 2375974 |
| seasonal breeding in two marsupials, the bandicoot isoodon macrourus and the possum trichosurus vulpecula. | 1990 | 2200044 | |
| mesotocin in the brain and plasma of an australian marsupial, the brushtail possum (trichosurus vulpecula). | oxytocic peptides extracted from the brain and plasma of the brushtail possum, trichosurus vulpecula, were separated by reverse-phase high pressure lipid chromatography (hplc) and quantified by specific radioimmunoassays for oxytocin (ot) and mesotocin (mt). the pituitary, hypothalamus and cerebral cortex were found to contain mt only in quantities of 3.9 +/- 0.2 (se) ug, 17.6 +/- 0.6 ng and 21.0 +/- 2.6 ng respectively. the plasma concentration of mt varied according to the degree of stress of ... | 1990 | 2082200 |
| influence of daylength on the initiation of the breeding season of the marsupial possum, trichosurus vulpecula. | in queensland, possums in the wild and in captivity first give birth during march and continue to give birth throughout the year until november. in this study the effect of short daylengths on the initiation of breeding activity was examined. one male and 4 female possums were transferred from an outside enclosure into a light control room (10 h light, 14 h dark) on 22 november. a control group of possums was housed in outside enclosures. the possums held in the light room gave birth 81.2 +/- 14 ... | 1990 | 2325020 |
| estrogen receptors in the adrenal cortex of the possum (trichosurus vulpecula). | 1. specific [3h]estradiol binding activity with characteristics of estrogen receptors was found in the cytosols and nuclear extracts of the adrenal cortex proper and special zone of the brushtail possum (trichosurus vulpecula). 2. the specific estradiol receptor had a sedimentation coefficient on sucrose gradients of approximately 9s and a molecular weight on gel filtration of more than 200,000. the adrenal cortex cytosol binds [3h]estradiol with high affinity (ka 5.5 x 10(9) m-1), and limited c ... | 1990 | 2361366 |
| neurogenesis in a marsupial: the brush-tailed possum (trichosurus vulpecula). ii. sensorimotor pathways. | the times of origin of neurons in sensorimotor pathways of the marsupial brush-tailed possum were determined with 3h-thymidine autoradiography. a series of 20 possums were injected with 3h-thymidine from postnatal days 5-95 and were normally allowed to survive until the brain cytoarchitecture was mature. brain stem and spinal sensorimotor regions were not labelled in our study and presumably form before birth in order to enable the newborn young to make the journey from the birth canal to the po ... | 1990 | 2245314 |
| neurogenesis in a marsupial: the brush-tailed possum (trichosurus vulpecula). i. visual and auditory pathways. | the times of origin of neurons in the visual and auditory systems were studied in a marsupial, the brush-tailed possum, using tritiated thymidine autoradiography. within the subcortical visual pathways, most neurons are generated between postnatal days 5 and 21, and the neurons of the primary visual cortex up to postnatal day 68. in the subcortical auditory pathways, most neurons are generated between postnatal days 5 and 28, and all auditory cortex neurons have appeared by postnatal day 46. neu ... | 1990 | 2245313 |
| cholinesterase activity in sensory-nerve endings, capillaries and motor end plates of the facial skin of the brush-tailed possum (trichosurus vulpecula). | the facial skin of two adult and one 50-day-old pouch animal of the marsupial mammal trichosurus vulpecula was removed after the animals has been suitably anesthetized and perfused for electron microscopy. small blocks of tissue (1 x 0.5 mm) were cut and incubated in acetylthiocholine iodide substrate for cholinesterase studies. the blocks were then subsequently postfixed in osmium tetroxide. thin sections were cut and stained with lead acetate. specific cholinesterase was found within the nerve ... | 1990 | 2075803 |
| identification of 5 alpha-androstane-3 alpha,17 alpha-diol in adrenal venous plasma of female possum (trichosurus vulpecula). | two hitherto unidentified c19 steroids were isolated from adrenal venous blood plasma of female possum (trichosurus vulpecula). they were 5 alpha-androstane-3 alpha,17 alpha-diol and its isomer 5 beta-androstane-3 alpha,17 alpha-diol. the compounds were isolated and identified by fractionation on paper chromatograms and hplc, followed by gas chromatography-mass spectrometry after conversion to trimethylsilyl ethers. in adrenal venous plasma the concentrations of the 5 alpha-isomer ranged from 24 ... | 1989 | 2724963 |
| identification of 5 beta-pregnane and 5 beta-androstane derivatives in adrenal venous and peripheral blood plasma of the female possum (trichosurus vulpecula). | in the possum a marked sex difference has been found in the steroids in adrenal venous plasma. four 5 beta-pregnane and four 5 alpha (beta) androstane derivatives together with ten 4-ene-3-keto steroids were isolated from the adrenal venous plasma of the female and definitively identified by gas chromatography-mass spectrometry. the major reduced steroids were: 5 beta-pregnane-3 alpha,17 alpha-diol-20-one and 5 beta-pregnane-3 alpha,17 alpha,20 alpha-triol, at concentrations of 52 +/- 12 microgr ... | 1989 | 2724960 |
| changes in milk composition during lactation in the common brushtail possum, trichosurus vulpecula (marsupialia: phalangeridae). | the milk constituents of trichosurus vulpecula, a folivorous marsupial, showed marked quantitative and qualitative changes during the course of lactation. the milk produced in the early stages of lactation was dilute, with about 9-13% (w/w) solids during the first 3 weeks, comprising mostly carbohydrate and protein (35-40%). at 20 weeks, about three-quarters of the way through lactation, the milk was much more concentrated, about 28% solids, with lipid the predominant fraction (30-35%), after a ... | 1989 | 2636424 |
| intestinal lactase (beta-galactosidase) and other disaccharidase activities of suckling and adult common brushtail possums, trichosurus vulpecula (marsupialia:phalangeridae). | small-intestinal disaccharidase activities of eight suckling t. vulpecula, aged from 34 to 150 days, and of two adult animals were investigated. intestinal maltase, isomaltase and sucrase activities increased with age, whereas lactase activities decreased. trehalase activities were relatively high in all animals and showed no obvious age-related changes. three separate beta-galactosidase activities, one neutral and two acid, acted on lactose. the neutral beta-galactosidase activity appeared to b ... | 1989 | 2517666 |
| changes in milk carbohydrates during lactation in the common brushtail possum, trichosurus vulpecula (marsupialia:phalangeridae). | milk samples (186) were obtained at various stages of lactation from 27 common brushtail possums (trichosurus vulpecula). qualitative and quantitative changes in the milk carbohydrates during early and mid-lactation were similar to those previously seen in other marsupials; the principal carbohydrate was lactose early in lactation and higher oligosaccharides in mid-lactation, and the hexose concentration reached a peak during mid-lactation. however, the late-lactation milk was unusual in that th ... | 1989 | 2561494 |
| a cyto-architectonic description of the thalamus of the tammar wallaby, macropus eugenii. | very few studies are available on the cyto-architectural features of the thalamus of metatherian mammals. most of these studies describe the thalamus of a polyprotodont metatherian, the north american opossum, didelphis virginiana. studies on diprotodont metatherians are fewer still. there are two descriptions of the thalamus of the australian possum trichosurus vulpecula. the only part of the thalamus that has been described in the wallabies is the lateral geniculate nucleus. hence, there was a ... | 1989 | 2765853 |
| immunocytochemical location of oxytocin and mesotocin within the hypothalamus of two australian marsupials, the bandicoot isoodon macrourus and the brushtail possum trichosurus vulpecula. | the presence of oxytocin and mesotocin in the hypothalamus of two australian marsupials, the bandicoot (isoodon macrourus) and the brushtail possum (trichosurus vulpecula), was examined by immunocytochemistry. tissue was fixed in paraformaldehyde in phosphate buffer and immunoreactive cells were detected using highly specific rabbit antioxytocin and sheep anti-mesotocin as primary antisera. immunoreactive oxytocin cells were demonstrated in the paraventricular and supraoptic nuclei of bandicoot ... | 1989 | 2767413 |
| a pmsg/gnrh method for the superovulation of the monovulatory brush-tailed possum (trichosurus vulpecula). | optimal ovarian stimulation with minimal degenerative changes was achieved in brush-tailed possums 3 days after a subcutaneous injection of 10 i.u. pmsg. this treatment alone did not result in ovulation and only rarely in oocyte maturation. ovulation of 8-24 mature oocytes occurred when on the 3rd day after 10 i.u. pmsg the female received 3 intramuscular injections of 50 micrograms synthetic gonadotrophin-releasing hormone (gnrh) 90 min apart. superovulation was achieved in immature, cycling, p ... | 1988 | 3045309 |
| osteogenesis in two marsupial species, the bandicoot isoodon macrourus and the possum trichosurus vulpecula. | skeletal development of two marsupial species, the bandicoot, isoodon macrourus and the brushtail possum, trichosurus vulpecula, has been examined in whole mount preparations using a technique of clearing and differential staining of cartilage and bone. both marsupials possess a complete cartilaginous skeleton at birth and ossification begins in the maxilla, mandible and certain bones of the forelimb soon after birth. the general pattern of ossification in these marsupials is similar to that in ... | 1988 | 3248963 |
| the ultrastructure of the pituitary and the adrenal gland of three newborn marsupials (dasyurus hallucatus, trichosurus vulpecula and isoodon macrourus). | the ultrastructure of the pituitary glands of the newborn northern native cat, brushtail possum and the northern brown bandicoot and the adrenal glands of the former two marsupials were examined to determine whether these endocrine glands were functional at birth. the anterior pituitary of all three species was well vascularised and many cells contained electron-dense, membrane bound granules. the adrenal glands were composed of two distinct cell populations. one group of cells possessed dark st ... | 1988 | 3364743 |
| ultrastructural identification of merkel cells around the mouth of the newborn marsupial. | the ultrastructure of the epidermal cells surrounding the mouth of three newborn marsupial species, the northern native cat dasyurus hallucatus, the brush tail possum trichosurus vulpecula and the northern brown bandicoot isoodon macrourus were examined. the presence of merkel cells, highly sensitive touch receptors, would suggest that the sense of touch aids the relatively underdeveloped newborn marsupial to move from the urinogenital sinus to the pouch and to locate the teat. | 1988 | 3364744 |
| the ultrastructure of the lung of two newborn marsupial species, the northern native cat, dasyurus hallucatus, and the brushtail possum, trichosurus vulpecula. | the lungs of newborn northern native cats, dasyurus hallucatus and newborn brushtail possums, trichosurus vulpecula were examined by both light and electron microscopy. the native cat has a birth weight of 18 mg after a gestation of about 21 days, whereas the brushtail possum weights 200 mg at birth and has a gestation period of 17.5 days. the lungs of the native cat are two large respiratory sacs, with a respiratory lining of squamous cells and surfactant-secreting cells. the capillaries are lo ... | 1988 | 3396063 |
| effect of dietary terpenes on glucuronic acid excretion and ascorbic acid turnover in the brushtail possum (trichosurus vulpecula). | 1. glucuronic acid was excreted in the urine of the brushtail possum, trichosurus vulpecula, in response to dietary terpenes (essential oils found in eucalyptus foliage). 2. the relationship between urinary glucuronic acid and the estimated terpene content of the diet was not equimolar, but varied from 1-17%, with levels of 5-39% found in animals maintained on terpenes or eucalypt leaves for several weeks. 3. blood levels of ascorbate and the turnover rate of ascorbate were increased in the brus ... | 1988 | 3356132 |
| factors influencing prostatic 5 alpha-reductase activity in possum (trichosurus vulpecula). | 1. there were marked differences in prostatic wts among individual possums, but no evidence of a seasonally related change in wt could be established. it was concluded that the wt differences are mainly due to the changes in secretory activities. after castration the prostate wts fell while after administration of testosterone or oestradiol partially reversed this process. 2. seven steroid conversion products were isolated from prostatic homogenates incubated with [3h] testosterone; 5 alpha-andr ... | 1988 | 3356127 |
| projection of cervical dorsal root fibers to the medulla oblongata in the brush-tailed possum, trichosurus vulpecula. | this study describes the projection of cervical spinal afferent nerve fibers to the medulla in the brush-tailed possum, a marsupial mammal. after single dorsal roots (between c2 and t1) were cut in a series of animals, the fink-heimer method was used to demonstrate the projection fields of fibers entering the cns via specific dorsal roots. in the high cervical spinal cord, afferent fibers from each dorsal root form a discrete layer in the dorsal funiculus. the flattened laminae from upper cervic ... | 1987 | 3630955 |
| effect of melatonin and removal of pouch young on the seasonality of births in the marsupial possum, trichosurus vulpecula. | melatonin implants were placed in 5 adult female possums during december. births were observed from 31 march to 12 april in 4 control possums, and on 16 january, 1 and 6 february, 27 march and 27 april in the melatonin-treated animals. melatonin would appear to have advanced the start of the breeding season in 3 of the 5 animals. following removal of pouch young a subsequent birth is more likely to occur when young are removed early in the breeding season. these results would suggest that daylen ... | 1987 | 3598964 |
| digestion and metabolism of high-tannin eucalyptus foliage by the brushtail possum (trichosurus vulpecula) (marsupialia: phalangeridae). | the digestion and metabolism of eucalyptus melliodora foliage was studied in captive brushtail possums (trichosurus vulpecula). the foliage was low in nitrogen and silica but high in lignified fibre and phenolics compared with diets consumed by most other herbivores. the high lignin content was suggested as the main cause of the low digestibility of e. melliodora cell walls (24%); microscopic observations of plant fragments in the caecum and faeces revealed few bacteria attached to lignified tis ... | 1987 | 3571567 |
| vulpecholic acid (1 alpha, 3 alpha, 7 alpha-trihydroxy-5 beta-cholan-24-oic acid): a novel bile acid of a marsupial, trichosurus vulpecula (lesson). | a novel trihydroxylated c24 bile acid was isolated from the gallbladder bile of the australian opossum, trichosurus vulpecula (lesson). this acid, for which the name vulpecholic acid is proposed, was identified as 1 alpha, 3 alpha, 7 alpha-trihydroxy-5 beta-cholan-24-oic. the structure proof included mass spectral and 1h and 13c nuclear magnetic resonance characterization of all crucial derivatives obtained by: oxidation of the methyl ester to a triketone with the enolizable 1,3-diketone functio ... | 1987 | 3559398 |
| evolution of mammalian x-chromosome inactivation: sex chromatin in monotremes and marsupials. | the inactive mammalian x-chromosome is always late-replicating, and in eutherian mammals it is heterochromatic and hypermethylated. we propose that this multistep system has evolved from a more primitive system, remnants of which may be found in marsupials and monotremes. the heterochromatic x (sex-chromatin body) is a distinctive feature of interphase cells of certain tissues in eutherian females but not males. thus we have searched for a sex-specific chromatin body in these same tissues in mar ... | 1987 | 3453040 |
| possums (trichosurus vulpecula) sharing dens: a potential infection route for bovine tuberculosis. | 1987 | 16031324 | |
| induction of adrenocortical special zone in the male possum (trichosurus vulpecula). | the induction of adrenocortical special zone (s.z.) by gonadotrophin administration was studied in male brush tailed possums. castrated males injected with porcine fsh (nih-fsh-p2) formed well developed s.z.s, varying in sizes from 5-20% of the gland's volume. pregnant mare serum gonadotrophin (pmsg) was ineffective. from adrenal homogenates of fsh treated possums incubated with [3h]-progesterone the major conversion products were 5 beta-reduced steroid metabolites (72%) and cortisol (4%). the c ... | 1987 | 2881677 |
| evolution of marsupials traced by their neurohypophyseal hormones: microidentification of mesotocin and arginine vasopressin in two australian families, dasyuridae and phascolarctidae. | neurohypophyseal hormones of two species belonging to the family dasyuridae, namely dasyurus viverrinus (eastern native cat) and dasyuroides byrnei (kowari), and of the single living member of the family phascolarctidae, phascolarctos cinereus (koala) have been isolated and characterized by their retention times in high-pressure reverse-phase partition chromatography and either amino acid composition or amino acid sequence through a gas-phase microsequencer. mesotocin and arginine vasopressin ha ... | 1987 | 3666414 |
| digestion and absorption ofeucalyptus essential oils in greater glider (petauroide svolans) and brushtail possum (trichosurus vulpecula). | measurements were made of the quantity and composition of the steam-volatile essential oils in gastrointestinal tract contents of greater gliders fedeucalyptus radiata foliage and brushtail possums fede. melliodora foliage. in both species, there was less oil in the stomach contents than in an equivalent mass of foliage. only minor losses of leaf oils occurred during mastication by greater gliders, and absorption from the stomach appeared to be the major reason for the difference in the oil cont ... | 1987 | 24301544 |
| plasma prolactin concentrations throughout lactation in the eastern quoll, dasyurus viverrinus (marsupialia:dasyuridae). | blood samples were collected throughout lactation from eight d. viverrinus, and the concentrations of prolactin in the plasma determined by an heterologous, double-antibody radioimmunoassay. for the first 45-50 days of lactation concentrations fluctuated between 2 and 80 ng/ml but were generally less than 60 ng/ml. they then increased sharply to over 120 ng/ml and greater than 200 ng/ml in some animals. levels began to decline after 120-130 days of lactation and were less than 40 ng/ml in all an ... | 1986 | 3789990 |
| changes in prolactin in peripheral plasma during lactation in the brushtail possum trichosurus vulpecula. | a heterologous double-antibody radioimmunoassay has been validated for prolactin in plasma and pituitary preparations of t. vulpecula. serial dilutions of crude pituitary homogenates and plasmas from several marsupials and purified prolactin from the tammar, macropus eugenii, showed parallel dose response curves. in both male and female possums plasma prolactin concentrations increased in response to a single intravenous injection of thyrotrophin releasing hormone. plasma prolactin concentration ... | 1986 | 3098213 |
| differences in steroid metabolism by testis, prostate and epididymis in the immature and adult possum (trichosurus vulpecula). | immature possums 126-195 days old and adults over 1 year old were used. testicular homogenates from immature possums converted [3h]progesterone to nine different products, of which greater than 63% were 5 alpha-reduced androstane metabolites. the major product from adult testis was testosterone in yields greater than 60%. while metabolism of [3h]testosterone by the epididymis of immature possum was minimal, in adults 5 alpha-reduced products constituted greater than 80% of the yield. in contrast ... | 1986 | 3757486 |
| immunolocalization of insulin, glucagon, pancreatic polypeptide, and somatostatin in the pancreatic islets of the possum, trichosurus vulpecula. | antibodies to insulin, glucagon, pancreatic polypeptide (pp), and somatostatin were used in the immunofluorescence procedure to demonstrate localization of the four hormones in cells of the pancreatic islets of the brushtailed possum, trichosurus vulpecula. most pancreatic islets revealed some differences in the topographical distribution and cell number of each endocrine cell type. insulin immunoreactive cells were observed in most islets where they occurred as groups of cells peripherally and ... | 1986 | 2881838 |
| geographic distribution of restriction types of mycobacterium bovis isolates from brush-tailed possums (trichosurus vulpecula) in new zealand. | dna restriction endonuclease analysis was used for intra-specific typing of mycobacterium bovis isolates from 83 brush-tailed possums (trichosurus vulpecula) obtained between 1982 and 1984 from the three major regions in new zealand with endemic bovine tuberculosis. all the isolates were found to be genetically very similar. differentiation of the isolates into 33 restriction types was achieved by using high-resolution electrophoresis and the combined results from separate digestions with the re ... | 1986 | 3016075 |
| absence of lymphokine-enhanced macrophage migration in vitro in the australian brush-tailed opossum, trichosurus vulpecula. | the supernatants from cultures of either opossum or guinea pig splenic lymphocytes, stimulated with phytohaemagglutinin, significantly enhanced the in vitro migration of guinea pig peritoneal macrophages (p greater than 0.001) but not that of opossum peritoneal macrophages. failure of opossum macrophages to respond to a putative macrophage chemotactic factor might account for the observed paucity of immune granulomas in these animals and help explain the species' susceptibility to tuberculosis. | 1986 | 3548027 |
| neuropeptide y-like immunoreactivity is absent from most perivascular noradrenergic axons in a marsupial, the brush-tailed possum. | noradrenergic perivascular axons were demonstrated in all systemic arteries and veins of a marsupial, the brush-tailed possum (trichosurus vulpecula), by a catecholamine fluorescence procedure and with antisera directed against the catecholamine-synthesizing enzymes tyrosine hydroxylase (th) and dopamine-beta-hydroxylase (d beta h). perivascular axons with neuropeptide y-like immunoreactivity (npy-li) were not found in most systemic arteries and veins using antisera which recognize npy and other ... | 1986 | 2879263 |
| long spinal and pyramidal actions on hindlimb motoneurons of the marsupial brush-tailed possum, trichosurus vulpecula. | the existence of descending propriospinal reflex linkages between forelimbs and hindlimbs has been established in the brush-tailed possum (trichosurus vulpecula). in animals under chloralose anesthesia and with intact brain stem, forelimb volleys evoked facilitation of flexor and extensor monosynaptic reflexes of both hindlimbs, more pronounced on the ipsilateral side. powerful inhibition of briefer latency and restricted to ipsilateral flexor digitorum longus (fdl) motoneurons was also brought ... | 1986 | 1255227 |
| parasites and serological survey of the common brushtail possum (trichosurus vulpecula) from kangaroo island, south australia. | 1986 | 3503151 | |
| weekly variations in body weight and plasma testosterone concentrations in the captive male possum, trichosurus vulpecula. | the possum is a seasonally breeding marsupial which gives birth in queensland from march through to september. to ascertain whether this seasonality in breeding is manifest in the male reproductive system, body weight and plasma testosterone concentrations were examined in five possums. plasma testosterone concentrations fluctuated throughout the year and a seasonal cycle was observed, with a peak in testosterone concentration in march and a nadir in september. body weights fluctuated in a simil ... | 1986 | 3781210 |
| effects of oestradiol, the oestrous cycle and pregnancy on weight, metabolism and cytosol receptors in the uterus of the brush-tail possum (trichosurus vulpecula). | uterine weight, rna, dna, protein content, in-vitro rate of protein synthesis, cytosol oestrogen and progesterone receptors were examined after administration of oestradiol to ovariectomized animals and on days 0, 5, 9 and 13 of the non-pregnant cycle and day 13 of pregnancy. in ovariectomized animals, oestradiol increased uterine weight, rna:dna and protein:dna ratios and the concentration of cytosol receptors for oestradiol and progesterone. during the oestrous cycle there was a linear increas ... | 1986 | 3950527 |
| the morphology of relay neurons in the dorsal lateral geniculate nucleus of the marsupial brush-tailed possum (trichosurus vulpecula). | the retinal terminal zones and the morphology of relay neurons within the dorsal lateral geniculate nucleus (lgnd) of the brush-tailed possum (trichosurus vulpecula) have been investigated with horseradish peroxidase (hrp) tracing techniques. anterograde transport of hrp from the retina confirmed previous descriptions of the laminar distribution of retinal afferents in this nucleus. in addition, it was found that lamina iii consists of two adjacent bands (iiia and iiib) of contralateral retinal ... | 1985 | 3998209 |
| structure of the uterine luminal epithelium of the brush-tailed possum (trichosurus vulpecula). | morphology and morphometry of the luminal surface of the uterus of the brush-tailed possum were studied during the oestrous cycle, in anoestrous animals and after ovariectomy. at oestrus the secretory cells were small and the epithelium heavily ciliated. the relative surface area occupied by secretory cells reached a maximum on day 13 when plasma progesterone concentrations are maximal. the mean apical surface area of the secretory cells also reached a maximum at this time. both these measures d ... | 1985 | 4045824 |
| peripheral androgen levels in the male brush-tail possum (trichosurus vulpecula). | radioimmunoassays were established for the measurement of total androgens and the specific measurement of testosterone and 5 alpha-dihydrotestosterone in peripheral plasma of the brush-tail possum. androgen concentrations were measured in blood collected from indwelling jugular cannulae to determine whether the normal pattern of androgen secretion in this species was episodic and to attempt to relate total androgen and the pattern of testosterone secretion to the changes previously reported in p ... | 1985 | 3989424 |
| identification of the major steroids in ovarian and adrenal venous plasma of the brush-tail possum (trichosurus vulpecula) and changes in the peripheral plasma levels of oestradiol and progesterone during the reproductive cycle. | the quantitatively major steroid hormones in ovarian and adrenal venous plasma of the female brush-tail possum were identified by gas chromatography-mass spectrometry. the ovarian vein plasma samples all contained oestradiol and its concentration was highest during the pro-oestrous phase of the reproductive cycle. during this phase the concentration of progesterone was below the limit of detection but at day 13 of the oestrous cycle and pregnancy, the concentration of progesterone exceeded that ... | 1985 | 3989423 |
| structure of the oviducal epithelium of the brush-tailed possum (trichosurus vulpecula). | observations were made using scanning and transmission electron microscopy and were correlated with measurements of the mean surface area and the percentage area occupied by secretory cells to provide precise interpretation of the morphological data. in cyclic and anoestrous possums the oviducts were lined with elaborate folds of mucosa except in the portion of the isthmus adjacent to the uterus where the pattern was much simplified. the folds decreased in height and number after ovariectomy. se ... | 1985 | 4038518 |
| some effects of breeding season and castration on the prostate and epididymis of the brushtail possum, trichosurus vulpecula. | in an attempt to understand the mechanism(s) responsible for the reported marked seasonal increase in prostatic, but not epididymal, weight in t. vulpecula, a number of parameters were measured in tissues from mature, entire males sampled within and outside of the breeding season and from castrates. conditions for the measurement of cytosol androgen receptors were also established. the weight of both the prostate and the epididymis was significantly elevated in the breeding season but the relati ... | 1985 | 2418813 |
| differences in steroidogenesis by the subcellular fractions of adrenocortical special zone and cortex proper of the female possum (trichosurus vulpecula). | steroidogenesis by subcellular fractions of adrenal cortex proper (c.p.) and special zone (s.z.) of female possum (trichosurus vulpecula) was studied. mitochondrial, microsomal and cytosol cell fractions were incubated with appropriate substrates in the presence of an nadph-generating system. the major products formed from [3h]progesterone and [3h]17 alpha-hydroxyprogesterone by the microsomal fraction of the c.p. were 11-deoxycortisol and 11-deoxycorticosterone and 3 alpha (beta)-hydroxy-5 alph ... | 1984 | 6597318 |
| hypertrophied adrenocortical tissue of the australian brush-tailed possum (trichosurus vulpecula): uniformity during reproduction. | adrenal glands from normal male and female brush-tailed possums (trichosurus vulpecula) were weighed and sectioned to investigate reported changes in the relative size of the hypertrophied region of the cortex during the reproductive cycle. total adrenal gland weight in normal females averaged 120 mg/kg body weight and the hypertrophied region occupied 40% of the gland volume. no significant variation was found in these figures between glands from pregnant, lactating and cyclic possums . in addi ... | 1984 | 6726106 |
| factors influencing the release of noradrenaline from hypothalamic slices of the possum, trichosurus vulpecula. | slices of hypothalamus of the possum, trichosurus vulpecula, were incubated with 3h noradrenaline and the subsequent spontaneous and k+-induced effluxes of 3h measured. unchanged 3h noradrenaline comprised virtually all the k+-induced efflux, indicating that there was little, if any, metabolism of the amine after its release. receptor-modulation of the k+-induced efflux of 3h was shown by inhibition of this efflux by noradrenaline, clonidine, angiotensin ii and leu-enkephalin, and by the increas ... | 1984 | 6497783 |
| phagocytosis of sperm cytoplasmic droplets by a specialized region in the epididymis of the brushtailed possum, trichosurus vulpecula. | during sperm maturation in the brushtailed possum, trichosurus vulpecula, cytoplasmic droplets are shed from maturing spermatozoa in the distal regions of the head of the epididymis. examination of luminal contents from various regions of the epididymis showed that the proportion of detached droplets in the luminal contents was reduced from about 45% in the proximal corpus epididymidis to less than 10% in the distal corpus and cauda epididymides. in contrast, the proportion of droplet-free sperm ... | 1984 | 6722242 |
| primary visual cortex in the brushtailed possum: receptive field properties and corticocortical connections. | the corticocortical connections and receptive field properties of primary or striate visual cortex of the brushtailed possum, trichosurus vulpecula, have been examined. in this australian marsupial species primary visual cortex has connections with four other visual areas in the occipital lobe. in these adjacent visual areas fibers from striate cortex terminate mainly in layers 3 and 4 and in some cases also in layers 1 and 2. in all four areas return connections to striate cortex originate pred ... | 1984 | 6093921 |
| metabolism of exogenous noradrenaline in slices of hypothalamus and caudate nucleus of the brush-tail possum, trichosurus vulpecula. | in the possum, trichosurus vulpecula, the major catecholamines in the hypothalamus and caudate nucleus are noradrenaline and dopamine, respectively, suggesting that catecholaminergic transmission in these regions is similar to that in eutherian mammalian brain. comparisons of accumulation and metabolism of 3h noradrenaline by tissue slices of the two regions indicated that in the caudate nucleus there was a seven-fold greater accumulation of unchanged noradrenaline but a lower rate of deaminatio ... | 1984 | 6497782 |
| gonadotrophin induced development of the "special zone" in the adrenal cortex of immature female possums (trichosurus vulpecula) with concomitant activation of steroid reductases. | the effect of gonadotrophin and oestradiol administration on adrenocortical special zone (s.z.) development and steroidogenesis was studied in immature female possums. adrenals were examined histologically to determine s.z. formation, and cell-free homogenates were incubated with 3h progesterone in the presence of an nadph-generating system. treatment with pms + hcg, resulted in the development of s.z.s. varying in volume from 10 to 60% of the total adrenal gland. this response was independent o ... | 1984 | 6509912 |
| ascorbic acid turnover and excretion in two arboreal marsupials and in laboratory rabbits. | rates of turnover and routes of excretion of 1-14c-ascorbic acid were compared among laboratory rabbits and two species of arboreal marsupials. ringtail possums (pseudocheirus peregrinus) exhibited higher blood ascorbate levels than either brushtail possums (trichosurus vulpecula) or rabbits, as well as greater pool sizes, shorter half-times and higher total entry rates of ascorbic acid. these differences were due partly to the high ascorbic acid content of eucalyptus foliage, the ringtail's die ... | 1984 | 6697698 |