Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| plasma levels of vitellogenin in chrysemys picta during the annual gonadal cycle: measurement by specific radioimmunoassay. | a ria for turtle (chrysemys picta) vitellogenin is described. after dimethylformamide precipitation of vitellogenin from the plasma of estrogen-treated female turtles, antibodies were developed in rabbits. the dimethylformamide precipitate was further purified by o-triethylaminoethyl cellulose column chromatography; the vitellogenin component eluted as a single peak. this material was used for iodination by a mild chloramine method. antibodies to turtle vitellogenin did not cross-react with plas ... | 1979 | 108085 |
| control of the interrenal gland of the freshwater turtle chrysemys picta in vivo and in vitro. | 2003 | 166009 | |
| the influence of mammalian and avian gonadotropins on in vitro ovarian steroid synthesis in the turtle (chrysemys picta). | 1976 | 179912 | |
| gonadotropin action and androgen synthesis in enzyme disperesed testicular cells of the turtle (chrysemys picta). | 1977 | 195861 | |
| plasma testosterone levels in male turtles, chrysemys picta, following single injections of mammalian, avian and teleostean gonadotropins. | 1977 | 195862 | |
| the effects of induced cold torpor and time of year on blood coagulation in pseudemys scripta elegans and chrysemys picta belli. | 1975 | 236129 | |
| functional characteristics of slowly adapting pulmonary stretch receptors in the turtle (chrysemys picta). | 1. single nerve fibre discharge has been recorded from slowly adapting pulmonary stretch receptors in single-pithed turtles on artificial ventilation. 2. receptor discharge during static and dynamic lung inflations showed that lung volume was the major stimulus of these receptors. the rate and degree of change in transpulmonary pressure were without direct effect. 3. the response of these receptors to static and dynamic lung inflation differed only quantitatively from those of bronchopulmonary s ... | 1979 | 480226 |
| optokinetic nystagmus and the accessory optic system of pigeon and turtle. | optokinetic nystagmus (okn) response functions were obtained in pigeon (columba livia) and turtle (chrysemys picta) before and after electrolytic lesions of the accessory optic nuclei (aon). postlesion retinal input to the aon was evaluated using standard autoradiographic techniques. bilateral destruction of aon in both pigeon and turtle did not abolish okn, but was correlated instead with a reduction in okn frequencies at high pattern velocities. a difference was observed between species with r ... | 1979 | 487063 |
| estrogen-binding proteins in the oviduct of the turtle, chrysemys picta: evidence for a receptor species. | estradiol-binding proteins in the reproductive tract of the turtle, chrysemys picta, were characterized. cytosol was prepared from the oviducts of mature female turtles, and estradiol binding was measured using charcoal adsorption and glycerol density gradient centrifugation. a sex steroid-binding protein (sbp) similar to that found in turtle plasma was demonstrated in oviduct cytosol. the characteristics of this sbp-like binding were as follows: ka = 10(8) m-1; capacity, 10(-12) mol/mg protein; ... | 1979 | 499079 |
| effects of hypothalamic extract and steroids on the secretion of prolactin, growth hormone and luteinizing hormone by the pituitary gland of the terrapin (chrysemys picta) in vitro. | 1978 | 624882 | |
| the annual ovarian cycle of chrysemys picta: correlated changes in plasma steroids and parameters of vitellogenesis. | 1978 | 689359 | |
| in vivo responses of female snakes (natrix fasciata) and female turtles (chrysemys picta) to ovine gonadotropins (fsh and lh) as measured by plasma progesterone, testosterone, and estradiol levels. | 1978 | 689361 | |
| proceedings: control of prolactin secretion in the terrapin (chrysemys picta). | 1975 | 812938 | |
| identification of aromatase in the reptilian brain. | the present study tests the hypothesis that brain aromatase is an "ancient" property of nervous tissue and may be identified in homologues of the limbic system in a non-mammalian vertebrate, the turtle chrysemys picta. tissue homogenates (180 mg wet weight/2 ml) were incubated with [7 alpha-3h]androstenedione and cofactors for 60 min at 37 c. estrone (e1) was isolated and characterized by thin layer chromatography, methylation and recrystallization to constant specific activity. no estradiol-17 ... | 1977 | 837883 |
| the effects of hormones on the reproductive physiology of the painted turtle, chrysemys picta. | 1977 | 881114 | |
| visual cortex in a reptile, the turtle (pseudemys scripta and chrysemys picta). | 1977 | 884523 | |
| interdigital cell death during limb development of the turtle and lizard with an interpretation of evolutionary significance. | cell death accompanies the formation of free digits in birds and mammals. however, in species with webbing between the adult digits, little or no cell death occurs in the prospectively webbed region of the developing interdigit. cell death does not occur during the formation of free digits in amphibians. in this paper we report that cell death accompanies the formation of the digits in snapping and painted turtles and in the skink (a lizard). we conclude that cell death accompanying the formatio ... | 1977 | 915430 |
| seasonal changes in testicular structure and function and the effects of gonadotropins in the freshwater turtle, chrysemys picta. | 1976 | 992355 | |
| antileptospiral activity in lower-vertebrate sera. | normal serum from the painted turtle (chrysemys picta), the snapping turtle (chelydra serpentina), and the frog (rana pipiens) were found to possess bactericidal activity towards leptospira. leptospires from both the parasitic and biflexa complexes were killed by these sera at high dilutions. this pattern differs from that of mammalian serum, as generally only the biflexa complex leptospires are killed by normal mammalian serum. the activity in c. picta serum was characterized as being complemen ... | 1975 | 1081972 |
| proceedings: influence of mammalian and avian gonadotrophins and prolactin on steroidogenesis in turtle (chrysemys picta) follicular and luteal tissues. | 1975 | 1151223 | |
| proceedings: the influence of mammalian gonadotrophins injected in vivo on testicular function in the normal and hypophysectomized male turtle (chrysemys picta). | 1975 | 1151260 | |
| the influence of oestradiol-17beta and progesterone on the contractility of the oviduct of the turtle, chrysemys picta, in vitro. | the contractility of the oviduct of chrysemys picta (the fresh-water turtle) was studied in vitro. significant regional differences in contractile activity were observed. contractions increased in amplitude and duration and decreased in frequency from the proximal to the distal end of the oviduct. injections of oestradiol-17beta in vivo increased the amplitude of contractions and decreased the duration of the rest period in segments taken from the diatal end of the oviduct. in contrast, progeste ... | 1976 | 1255052 |
| striatal afferent connections in the turtle (chrysemys picta) as revealed by retrograde axonal transport of horseradish peroxidase. | horseradish peroxidase (hrp, 30% solution, 0.1-0.3 mul, 72 h) was injected unilaterally into the basal striatum (str) and the dorsal ventricular ridge (dvr) of adult turtles (chrysemys picta) in order to demonstrate the cells of origin of some afferents to these telencephalic structures. after selective str injection, hrp-labeled cells were visualized in the dorsal thalamus and midbrain tegmentum, ipsilaterally. at thalamic level, hrp-positive neurons were located around nucleus rotundus, i.e., ... | 1976 | 1276890 |
| roles of catecholamines and corticosterone during anoxia and recovery at 5 degrees c in turtles. | the roles of the catecholamines and corticosterone in glucose regulation during 28 days of submergence anoxia and air-breathing recovery at 5 degrees c in the turtle chrysemys picta were examined. anoxia resulted in an increase in mean plasma epinephrine and norepinephrine levels (from 42 and 49 to 966 and 3,826 pg/ml, respectively) and a decrease in hepatic glycogen levels. despite the increase in plasma catecholamine levels, plasma glucose levels did not change, and the percent of the alpha fo ... | 1992 | 1415786 |
| putative apolipoprotein b-100 in the freshwater turtle chrysemys picta: effects of estrogen and progesterone. | 1. the isolation and purification of a putative apolipoprotein b-100 in the plasma of the freshwater turtle chrysemys picta is described. 2. the protein was purified through differential ultracentrifugation and subsequent sepharose 6b column chromatography. 3. the molecular weight of the protein determined by electrophoresis was approximately 350 kda. 4. an antibody to chicken apolipoprotein b-100 specifically recognizes this 350 kda protein in western blots, suggesting its identity with apolipo ... | 1992 | 1458844 |
| metabolic and cardiodynamic responses of isolated turtle hearts to ischemia and reperfusion. | we used 31p and 1h nuclear magnetic resonance spectroscopy to measure intracellular ph, high energy phosphates, and lactate levels in hearts of turtles (chrysemys picta bellii) subjected to 1.5 h of global ischemia followed by reperfusion. we simultaneously monitored maximum ventricular developed pressure (pmax), maximal rate of pressure development (dp/dtmax), rate-pressure product (rpp), cardiac output, and heart rate and also measured lactate efflux from the hearts during reperfusion. our goa ... | 1992 | 1558214 |
| natural freezing survival by painted turtles chrysemys picta marginata and c. picta bellii. | hatchlings of both the midland (chrysemys picta marginata) and western (c. picta bellii) subspecies of the painted turtle tolerate the freezing of extracellular body fluids while overwintering in terrestrial nests. fall-collected hatchlings survived 3 days of continuous freezing at -2.5 degrees c, with ice contents of 43.5 +/- 1.0% of total body water (se; n = 24) for c. picta marginata and 46.5 +/- 0.8% (n = 32) for c. picta bellii. survival times dropped to 4-5 h when temperature was lowered t ... | 1992 | 1558223 |
| the effect of anoxic submergence and recovery on circulating levels of catecholamines and corticosterone in the turtle, chrysemys picta. | the ability of some freshwater turtles to tolerate prolonged anoxia is well known. the role of hormones in the regulation of the metabolic adjustments that occur during anoxia, however, is unknown. this study examined the changes in plasma glucose, lactate, catecholamine, and corticosterone levels during submergence anoxia and recovery at 22 degrees c in the painted turtle, chrysemys picta. plasma catecholamine levels increased greatly during anoxia, while corticosterone levels decreased. during ... | 1992 | 1601262 |
| responses to freezing exposure of hatchling turtles trachemys scripta elegans: factors influencing the development of freeze tolerance by reptiles. | hatchling red-eared turtles trachemys (= pseudemys) scripta elegans (wied) from a louisiana population display a significant ability to withstand the freezing of extracellular body fluids. all animals survived at least 2 h of freezing at -2.5 or -4 degrees c. at -2.5 degrees c, survival declined to 50% after 6 h of freezing and no animals recovered after 24 h or longer, when mean ice content reached 54.7 +/- 1.4% of total body water. at -4 degrees c, all turtles recovered from 4 h of freezing ex ... | 1992 | 1634864 |
| evidence for gabaergic interneurons in the red nucleus of the painted turtle. | immunocytochemical and electrophysiological evidence supporting the presence of gabaergic interneurons in the turtle red nucleus is presented. injections of hrp into the spinal cord produced labeling of large neurons in the contralateral red nucleus. the peroxidase-antiperoxidase (pap) method revealed smaller cells immunoreactive to an antibody against glutamate decarboxylase (gad), the synthetic enzyme for the inhibitory neurotransmitter gaba, that were interspersed among larger immunonegative ... | 2006 | 1636150 |
| catecholamine stimulation of hepatic glycogenolysis during anoxia in the turtle chrysemys picta. | the remarkable tolerance of some species of turtles to anoxia is well documented. the role that hormones play in this anoxia tolerance, however, is poorly understood. this study examined the role of catecholamines in the mobilization of liver glycogen during anoxic submergence in painted turtles (chrysemys picta). turtles were subjected to 4 h of submergence anoxia or air (normoxic controls) and received injections of propranolol, a beta-adrenergic receptor antagonist, or saline. the results ind ... | 1991 | 1661097 |
| excitatory amino acid receptor-mediated transmission in geniculocortical and intracortical pathways within visual cortex. | 1. a preparation of turtle (chrysemys picta and pseudemys scripta) brain in which the integrity of the intracortical and geniculocortical pathways in visual cortex are maintained in vitro has been used to differentiate the excitatory amino acid (eaa) receptor subtypes involved in geniculocortical and intracortical synapses. 2. stimulation of the geniculocortical fibers at subcortical loci produces monosynaptic excitatory postsynaptic potentials (epsps) in visual cortical neurons. these epsps are ... | 1991 | 1681038 |
| channel arrest: implications from membrane resistance in turtle neurons. | a widespread defense strategy used by hypoxia-tolerant animals is metabolic depression. one possible mechanism for metabolic depression is "channel arrest." this hypothesis predicts that ion leakage through plasma membrane leakage channels is reduced during an anoxic episode. the decreased ion flux would result in the conservation of energy through the reduction of atp-demanding ion pumping. we tested this hypothesis with the anoxia-tolerant turtle (chrysemys picta) as a model system. with intra ... | 1991 | 1719828 |
| allometry of cooling, supercooling, and freezing in the freeze-tolerant turtle chrysemys picta. | although several vertebrates are freeze tolerant, little is known of the relationship between body size and the kinetics of cooling and freezing. we compared these responses for six hatchling and eight adult chrysemys picta from an ohio population. all turtles initially recovered from freezing, and all adults, but only two hatchlings (which experienced ice contents of approximately 35%), exhibited long-term survival. rapid thawing may have compromised hatchling survival. turtle water content was ... | 1991 | 1887950 |
| 31p-nmr study of normoxic and anoxic perfused turtle heart during graded co2 and lactic acidosis. | we studied the effects of graded acidosis (both co2 and lactic acid) and anoxia on intracellular ph (phi) regulation, high-energy phosphates, and mechanical function of isolated perfused hearts of the turtle (chrysemys picta bellii) at 20 degrees c using 31p-nuclear magnetic resonance (nmr) spectroscopy. during co2 acidosis, anoxia had no effect on apparent nonbicarbonate buffer value (d[hco3-]/dphi = 71 and 89 mm/ph in normoxia and anoxia, respectively) or on phi regulation (dphi/dphe = 0.52 an ... | 2006 | 1905494 |
| effects of anoxia and graded acidosis on the levels of circulating catecholamines in turtles. | we measured circulating levels of catecholamines in painted turtles subjected to anoxia with different degrees of concomitant acidosis at 20 degrees c and in turtles subjected to long-term submergence at 3 and 10 degrees c. blood levels of both epinephrine (e) and norepinephrine (ne) increased during n2-breathing, n2/co2 breathing and submergence, with ne generally being present in higher concentrations than e. during submergence at 20 degrees c, anoxic turtles experienced an extreme acidosis an ... | 1991 | 1925113 |
| oxidative cost of breathing in the turtle chrysemys picta bellii. | we estimated the cost of breathing of turtles by measuring ventilation and oxygen consumption during air breathing and co2 breathing. we assumed that any increment in oxygen consumption due to hypercapnic hyperpnea was due to the metabolic cost of the increased breathing. six turtles were studied while breathing air and then 5% co2 in air after at least 12 h breathing each gas. for the measurements, the turtles were submerged unrestrained in water at 20 degrees c and were free to raise their hea ... | 2007 | 1951782 |
| extracellular and intracellular acid-base effects of submergence anoxia and nitrogen breathing in turtles. | we compared extracellular and intracellular acid-base state in turtles (chrysemys picta bellii) subjected to anoxic submergence to turtles made anoxic by n2-breathing. measurements made on control animals and on animals after 1, 2, 4, or 6 h of anoxia included blood ph, po2, pco2, and lactate as well as liver, heart, skeletal muscle, and brain phi (using dmo equilibration), lactate, and glycogen concentrations. we hypothesized that the anaerobic metabolic rate of submerged turtles would be depre ... | 1991 | 2068419 |
| life in a frozen state: adaptive strategies for natural freeze tolerance in amphibians and reptiles. | winter survival for various species of amphibians and reptiles that hibernate on land depends on freeze tolerance, the ability to survive for long periods of time with up to 65% of total body water as extracellular ice. freeze tolerance has been described for four species of frogs, one salamander, and hatchlings of the painted turtle. a very limited tolerance also occurs in garter snakes. studies of freeze tolerance in vertebrates have primarily focused on the wood frog rana sylvatica and have a ... | 1990 | 2180324 |
| localization of insulin to gastroenteropancreatic cells in the turtle gastrointestinal tract. | insulin has been localized immunocytochemically to open-type gastroenteropancreatic endocrine cells in sections of bouin's-fixed upper, middle, and lower intestine from chrysemys picta, pseudemys scripta scripta, p. scripta elegans, p. floridana, sternotherus odoratus, and trionyx spinifer asper. radioimmunoassay of extracts of mucosal scrapings from chrysemys intestine indicates differential amounts of insulin-like immunoreactivity within the intestine (higher amounts in the lower intestine) an ... | 1990 | 2185121 |
| insulin cells are found in the main and accessory urinary bladders of the painted turtle, chrysemys picta. | insulin has been localized immunocytochemically to cells in the main and accessory urinary bladders of the painted turtle, chrysemys picta, and represents an unusual addition to the specturm of regulatory peptides associated with the urinary bladder. these stellate to fibroblastoid cells often possess neural-like processes and are similar in morphology to neurotensin cells found in chrysemys and pseudemys urinary bladders. radioimmunoassay of 2m acetic acid extracts of bladder tissue indicate th ... | 1990 | 2189021 |
| neurotensin is localized to paracrine cells in the urinary bladder of the turtle, chrysemys picta. | urinary bladder from the painted turtle, chrysemys picta, contains a substantial population of endocrine/paracrine cells scattered through the mucosal epithelium which immunostains using antisera directed toward mammalian neurotensin (nt). radiommunoassay of 0.1 n hcl extracts of chrysemys bladder indicated an immunoreactive nt (int) concentration of 161 +/- 39 pmol/g tissue (n = 9), an amount lower but comparable in magnitude to that found in mucosal scrapings of the intestine (926 +/- 125 pmol ... | 1990 | 2202609 |
| aerobic metabolism and swimming energetics of the painted turtle, chrysemys picta. | oxygen consumption rates (vo2) were measured for painted turtles (chrysemys picta) swimming in a respirometer at controlled speeds. sustained specific swimming speeds ranged from 0.75 to 1.52 body lengths (l) per s. over most of this range endurance exceeded 30 min. vo2 increased curvillinearly with swimming speed (u) and the maximum active rate was 9 times resting (0.26 ml o2/min), and 3 times routine (0.64 ml o2/min). mass specific metabolic scope was 228 ml o2/(kg.h), similar to that reported ... | 1990 | 2365028 |
| force and acid-base state of turtle cardiac tissue exposed to combined anoxia and acidosis. | we measured contractile force of ventricular strips form the turtle chrysemys picta bellii exposed to 1 h of combined anoxia and acidosis (ph 7.0) at 20 degrees c. strips either beat spontaneously (self-paced) or in response to electrical stimulation (paced at 12, 24, or 36 beats/min). tissue [lactate] and intracellular ph (phi) were measured in control strips and at the end of anoxia-acidosis. in self-paced strips, at normal extracellular ca2+ concentration ([ca2+]o) (1 mm), both rate and force ... | 1990 | 2375425 |
| 31p-nmr measurements of phi and high-energy phosphates in isolated turtle hearts during anoxia and acidosis. | we used 31p-nuclear magnetic resonance (nmr) spectroscopy to measure intracellular ph (phi) and high-energy phosphate levels in hearts of turtles (chrysemys picta bellii) during either 4 h of anoxia [extracellular ph (pho) 7.8, 97% n2-3% co2], 4 h of lactic acidosis (pho 7.0, 97% o2-3% co2), or 1.5 h of combined anoxia + lactic acidosis (pho 7.0, 97% n2-3% co2) followed by 2 h of oxygenated recovery (pho 7.8) at 20 degrees c. we also measured heart rate, maximum ventricular-developed pressure, a ... | 1990 | 2396711 |
| a simplified model for bivariate complex allometry. | a three-parameter relationship passing through the origin can be derived from the gompertz growth curve and provide a simplified but useful description of complex allometry, where variates are not proportional to powers of each other as in simple allometry. partial linearization is often satisfactory and, after a double logarithmic transformation, the allometric relationship is non-linear only with respect to an exponent of complex allometry, d, which reflects the presence (e # 1) or absence (d ... | 1989 | 2615392 |
| cloned rainbow trout liver p(1)450 complementary dna as a potential environmental monitor. | a technique is proposed for the biological monitoring of pollutants in aquatic environments by use of a complementary dna (cdna) probe. the induction of hepatic cytochrome p(1)450 mrna has been investigated utilizing pfp(1)450-3', a 3'-specific 1.5 kb cdna clone derived from 3-methylcholanthrene-inducible mrna of rainbow trout. a time course of induction of both the hybridizable mrna and hepatic monooxygenase catalytic activity in rainbow trout with a known inducer in fish, beta-naphthoflavone, ... | 1989 | 2711397 |
| nuclear acceptor sites for estrogen-receptor complexes in the liver of the turtle, chrysemys picta. i. sexual differences, species specificity and hormonal dependency. | hepatic estrogen receptors (ers) of the female turtle, chrysemys picta, when complexed with [3h]estradiol ([3h]e2), were shown to bind specifically to liver chromatin isolated from the same species. the binding of the [3h]e2 receptor complex to chromatin requires both the steroid ligand and the receptor protein. maximal binding occurred within 60-70 min of incubation at 4 degrees c in a tris buffer containing 0.1 m kcl. the binding of the [3h]e2 receptor complex to intact chromatin was saturable ... | 1989 | 2744216 |
| two progesterone receptors in the oviduct of the freshwater turtle chrysemys picta: possible homology to mammalian and avian progesterone receptor systems. | two progesterone receptors in the oviduct of the freshwater turtle chrysemys picta: possible homology to mammalian and avian receptor systems. here we report the characterization of two specific progesterone receptors in nuclear extracts of the turtle oviduct. the receptors differ in dissociation constants (2.8 nm vs 27 nm) which can be separated on deae-sepharose, the former eluting at 0.08 m kcl and the latter at 0.20 m kcl. [3h]r5020 photoaffinity labeling sds-page revealed that the 2.8 nm mo ... | 2009 | 2770302 |
| effects of hypophysectomy and ovariectomy on hepatic estrogen receptor content in the turtle, chrysemys picta. | estrogen receptor (er) content in the cytosol and nuclear extract of the liver of adult female chrysemys picta (control females) was measured in february, may, early june, and late june. both cytosolic (c) and nuclear (n) hepatic er content rose from low levels (c: 189 +/- 19; n: 52 +/- 23 fmol/g tissue) in february to significantly higher levels in may (c: 437 +/- 15; n: 124 +/- 25 fmol/g tissue) before declining to lower values in early june (c: 298 +/- 19; n: 118 +/- 20 fmol/g tissue) and lat ... | 1989 | 2792732 |
| seasonal variation in hepatic binding of estrogen in the turtle, chrysemys picta. | the present study describes the seasonal changes of the estrogen receptor (er) system in the liver of the turtle, chrysemys picta. [3h]estradiol ([3h]e2) binding capacities and affinities of liver cytosols and nuclear extracts were measured with established procedures and analyzed by scatchard plots. our data revealed significant seasonal variations in both receptor content and the er's affinity for [3h]e2 in the liver of the turtle. nuclear er content remained at a fairly stable level of 70 fmo ... | 1989 | 2792733 |
| a nonparametric comparison of monomolecular growth curves: application to western painted turtle data. | intractable distributional assumptions are generated in parametric analyses comparing groups of subjects described by nonlinear growth models. the distributional situation becomes more complex when pointwise mean curves best describe group growth (instead of curves based on mean parameters). an interval specific randomization test is developed to handle monomolecular growth models. the need for the technique was motivated by a study describing longitudinal growth data from the annuli on abdomina ... | 2006 | 2807647 |
| the viability of nearctic freshwater turtles submerged in anoxia and normoxia at 3 and 10 degrees c. | survival times of temperature-acclimated freshwater turtles submerged in normoxic and anoxic water were determined. juvenile chrysemys scripta from alabama and adult chrysemys picta bellii from wisconsin exhibited the maximal survival times of the 10 species and subspecies investigated, both being able to survive at least a half-year of submergence at 3 degrees c in normoxic water. minimal viability was exhibited by sternotherus odoratus and trionyx spiniferus submerged in anoxia at 10 degrees c ... | 1985 | 2863050 |
| the effects of cold acclimation on electrocardiogram parameters in five species of turtles. | the effects of thermal acclimation at 25 or 5 degrees c on electrical activity in the heart were investigated in pseudemys scripta, terrapene carolina, chrysemys picta marginata, chrysemys picta dorsalis, chelydra serpentina, and sternotherus odoratus. the durations of the qrs complex and p-r, r-t and r-r intervals were found to increase with decreasing body temperature in all animals tested. the amplitudes of the p and t waves and qrs complex were dependent upon both acclimation temperature and ... | 1987 | 2886260 |
| metabolic rate of feeding and fasting juvenile midland painted turtles, chrysemys picta marginata. | 1. resting metabolic rates at 25 degrees c were determined for juvenile midland painted turtles that had recently been fed or fasted for 1, 2, 4, 6, 10, 14 or 19 days. 2. recently fed turtles had an oxygen consumption rate of 211 microliter o2/g/hr. this decreased by 32% on the first day of the fast and by 69% by the 19th day. 3. mass of the turtles (4.91-14.30 g) did not affect the rate of oxygen consumption (vo2). | 1988 | 2900100 |
| characterization of steroid receptors in the gut and kidney of the frog (rana catesbeiana) and in the gut of the turtle (chrysemys picta). | paraglucocorticoid- and paramineralocorticoid-binding cytosolic receptors (pgr, pmr) were demonstrated in the intestine and kidney of the frog, rana catesbeiana and in the intestine of the turtle, chrysemys picta, in the presence of sodium molybdate. these receptors were of high affinity and low capacity with the following binding parameters: pgr:kd:frog intestine (fi), triamcinolone acetonide (ta): 3.3 nm, corticosterone (b): 3.4 nm; frog kidney (fk), ta:4.3 nm, b: 9.3 nm; turtle intestine (ti) ... | 1987 | 3035288 |
| changes in ventilation and breathing pattern produced by changing body temperature and inspired co2 concentration in turtles. | respiratory minute ventilation (ve), breathing pattern, oxygen consumption (vo2) and arterial blood gases and ph were measured in freshwater turtles (chrysemys picta) at 10, 20 and 30 degrees c while the animals breathed gases of varying co2 concentration (fico2 = 0, 2, 4, 6 and 8%). increasing body temperature produced unequal increases in ve and vo2 such that ve/vo2 decreased. this relative hypoventilation led to a rise in paco2 and fall in pha. increasing fico2 at all temperatures greatly ele ... | 2011 | 3103185 |
| effects of thyrotropin-releasing hormone in vitro on thyrotropin and prolactin release from the turtle pituitary. | effects of synthetic thyrotropin-releasing hormone (trh) on thyrotropin (tsh) and prolactin (prl) release by hemipituitaries of adult turtles, chrysemys picta, were studied in an in vitro superfusion system. significant increases in the rates of secretion of both immuno-reactive tsh and prl occurred at doses between 0.01 and 10 ng/ml trh. tsh secretion increased acutely by two-, to sixfold over nonstimulated secretion levels; responses tended to decline after many hours of continual stimulation, ... | 1987 | 3114044 |
| brain and cerebrospinal fluid ion composition after long-term anoxia in diving turtles. | prolonged anoxia in turtles is associated with marked disturbances in plasma composition. this study examines brain and cerebrospinal fluid (csf) ion homeostasis in the freshwater turtle, chrysemys picta bellii, in response to 8-10 days of submergence anoxia at 10 degrees c. for comparison, it also examines the response to experimental elevation of plasma [k], [ca], and [mg] in normoxic turtles. long-term anoxia resulted in marked changes in brain and csf composition. these included elevated [k] ... | 1988 | 3136673 |
| hatchling turtles survive freezing during winter hibernation. | hatchlings of the painted turtle (chrysemys picta marginata) are unique as the only reptile and highest vertebrate life form known to tolerate the natural freezing of extracellular body fluids during winter hibernation. turtles survived frequent exposures to temperatures as low as -6 degrees c to -8 degrees c in their shallow terrestrial nests over the 1987-1988 winter. hatchlings collected in april 1988 had a mean supercooling point of -3.28 +/- 0.24 degrees c and survived 24 hr of freezing at ... | 1988 | 3186730 |
| the annual testicular cycle in the turtle, chrysemys picta: a histochemical and electron microscopic study. | this work is a study of testicular function in chrysemys picta using changes in ultrastructure and steroid histochemistry as indices of leydig and sertoli cell activity. the cytological features of these cells are described in reference to four periods of tubular development. leydig and sertoli cells show distinct changes in morphological appearance during the seasonal cycle. leydig cells are hypertrophic with an active 3 beta-hydroxysteroid dehydrogenase (hsd) and abundant smooth endoplasmic re ... | 1988 | 3203868 |
| seasonal variations in oviductal activity, extensibility, and tensile strength in chrysemys picta. | in vivo and in vitro myometrial activity, tissue extensibility, and tensile strength were measured during the annual cycle of the female turtle chrysemys picta. contractile rate, in vivo and in vitro, increased to a maximum in the periovulatory period, but contractile strength in vitro was inversely proportional to rate, being least in the periovulatory period. initial oviductal circumference was highest in april and lowest in september. although extensibility varied little, this parameter was i ... | 1988 | 3240854 |
| sex hormone binding globulin levels and free progesterone, testosterone and estradiol 17 beta during the annual cycle of the female turtle, chrysemys picta. | significant changes in % free serum e2, t and p were observed during the annual cycle of the turtle. in contrast no significant changes in shbg affinity constants (2.29-4.48 x 10(8) m-7) were found and binding capacity for estradiol 17b was between 3.47 and 3.96 x 10(-7) m except in preovulatory animals (2.00 +/- 0.25). | 1988 | 3250020 |
| hemoglobins of reptiles. the primary structure of the major and minor hemoglobin component of adult western painted turtle (chrysemys picta bellii). | red blood cells of adult western painted turtles (chrysemys picta bellii) contain two hemoglobin components: hba (alpha a2 beta 2) and hbd (alpha d2 beta 2). we present the complete amino-acid sequences of the alpha a-chains from the major component and of the beta-chains common to both components. structural features are discussed with respect to the animals extreme tolerance of severe hypoxic conditions during hibernation which is accompanied by a high oxygen affinity of the hemoglobin. the st ... | 1988 | 3365328 |
| riboflavin-binding protein from reptiles: a comparison with avian riboflavin-binding proteins. | 1. riboflavin-binding protein (rbp) has been isolated for the first time from reptilian sources. 2. rbp from eggs of python molurus (indian python) and chrysemys picta (painted turtle) has been isolated and compared to rbp from gallus gallus domesticus (chicken), a well-characterized protein, and a newly isolated rbp from cairina moschata (muscovy duck). 3. each of the proteins is phosphorylated and glycosylated. 4. the ratio of riboflavin binding to protein is 1:1 and the kd for each protein is ... | 1988 | 3396329 |
| hepatic progesterone receptors: characterization in the turtle chrysemys picta. | high and low affinity progesterone (p)-binding proteins similar to those described in the chick oviduct were characterized for the first time in liver cytosol in an oviparous turtle, chrysemys picta. two forms of high affinity p receptor were separated by diethyl aminoethyl (deae)-sepharose anion exchange chromatography; the a form eluted in low salt buffer, and the b form at a kcl concentration of 0.20 m in a linear gradient. after photoaffinity labeling of crude cytosol with [3h] r5020, two ov ... | 2012 | 3396503 |
| high-affinity binding of [3h]estradiol-17 beta by an estrogen receptor in the liver of the turtle. | specific [3h]estradiol-17 beta ([3h]e2) binding activity (eba) with characteristics of an estrogen receptor (er) was demonstrated in cytosols and nuclear extracts of the female turtle, chrysemys picta. three different receptor assays (dextran-coated charcoal assay, hydroxylapatite batch procedure, and dna-cellulose chromatography) were evaluated in terms of their applicability in analyzing large numbers of samples. for the measurement of cytosolic eba, the hydroxylapatite batch procedure was fou ... | 2010 | 3417113 |
| morphological constraint on egg size: a challenge to optimal egg size theory? | some freshwater turtles appear unable to produce eggs large enough to achieve the balance between size and number of eggs predicted by optimal egg size theory. we present evidence that pelvic girdle structure constrains egg size and thus offspring size in females of smaller-bodied species (chrysemys picta and deirochelys reticularia). the constraint is demonstrated by the correspondence of slopes of the increase of the pelvic aperture and egg width with increasing body size. this constraint appe ... | 1987 | 3473499 |
| specificity of amphibian and reptilian pituitaries for various forms of gonadotropin-releasing hormones in vitro. | in vitro perifusion was employed to compare the potencies of mammalian, avian, salmon, and lamprey gonadotropin-releasing hormones (gnrhs) on the release of luteinizing hormone (lh) from the pituitaries of an amphibian (rana pipiens) and a reptile (chrysemys picta). the chicken-i and salmon gnrh variants were equipotent with mammalian gnrh in both the frog and the turtle glands. by contrast, the lamprey gnrh was inactive (less than 1% as potent as the others). lamprey gnrh also failed to stimula ... | 1987 | 3556314 |
| ultrastructure of the dorsal lateral geniculate complex in turtles of the genera pseudemys and chrysemys. | the ultrastructure of the dorsal lateral geniculate complex in the turtles pseudemys scripta elegans and chrysemys picta belli has been studied. the majority of neurons have somata situated in a cell plate that forms the medial face of the complex. relatively few synaptic contacts occur on the somata of cell plate neurons, but three types of axon terminals contact their proximal dendrites as they course through the cell plate. the most frequent are terminals with clear, round synaptic vesicles t ... | 1986 | 3594200 |
| acid-base status and electrolytes in red blood cells and plasma of turtles submerged at 3 degrees c. | two groups of adult chrysemys picta bellii were studied; control turtles were maintained at 24 degrees c with free access to air, and diving animals were continuously submerged for 8.5-9.5 wk in aerated water at 3 degrees c. cold submergence elicited a substantial lactic acidosis (blood ph 7.70; plasma [lactate-] 42.5 meq/l h2o). this acid load was largely balanced by changes in plasma strong ions; [cl-] decreased, and [ca2+] and [mg2+] increased. phosphorus nuclear magnetic resonance showed a s ... | 1987 | 3605391 |
| ionic compensation with no renal response to chronic hypercapnia in chrysemys picta bellii. | the ionic compensatory response to co2 breathing for 3 days was studied on intact and cystectomized turtles at 10 and 20 degrees c. arterial blood gases, ph, ionized calcium, and the plasma concentrations of na+, k+, cl-, total ca2+, and total mg2+ were measured periodically. at 20 degrees c, ureteral urine was also collected from bladderless turtles and was analyzed for ph, ions, nh3+, total co2, osmolality, and titratable acid. when co2 was breathed there was a compensatory change in the stron ... | 1986 | 3789204 |
| steroid hormones reverse sex in turtles. | injection of estradiol benzoate into eggs of snapping turtles and painted turtles caused all embryos to develop as females. a similar but less consistent female-determining effect was associated with injection of testosterone proprionate. both species of turtles have temperature-dependent sex determination in nature, whereby embryos incubated at cool temperatures (25 degrees) develop as males and embryos incubated at warm temperatures (31 degrees) develop as females. exogenous estrogens have bee ... | 1986 | 3803892 |
| hepatic estrogen receptor in the turtle, chrysemys picta: partial characterization, seasonal changes and pituitary dependence. | a hepatic estrogen receptor is described from female turtles, chrysemys picta. the receptor adheres to dna after incubation with [3h]estradiol and can be eluted with a linear salt gradient as a single component with an elution maximum of 0.21 m. it is steroid-specific, binding estrogens, but not androgens or progestins. specific binding saturates between 3 and 7 nm [3h]estradiol-17 beta and scatchard analysis gave a kd of 2 x 10(-9) m and a maximal binding capacity of 3.02 fmol/mg protein. hypop ... | 1987 | 3821107 |
| lh secretion in response to gonadotropin releasing hormone (gnrh) by superfused pituitaries from two species of turtles. | a superfusion system was employed to study the dynamics of the responses of lh secretion to gonadotropin releasing hormone (gnrh) by anterior pituitary glands (quartered) from adult turtles, pseudemys scripta and chrysemys picta. responsiveness was highly variable in both species, but in many cases, the tissues showed marked responses to relatively low doses (2-20 ng/ml) of gnrh. gnrh had no effect on lh secretion in five female p. scripta tested in the month of august, whereas it stimulated mos ... | 2014 | 3899857 |
| the gastro-entero-pancreatic system of the turtle, chrysemys picta. | pancreatic endocrine cells were stained immunocytochemically for insulin, glucagon, somatostatin and pancreatic polypeptide by the pap technique or sequentially for two hormones by the pap followed by an indirect immunogold procedure. pancreatic endocrine cells of chrysemys are found scattered as single cells or small aggregates throughout the exocrine parenchyma; only the splenic region shows islets consisting of a b cell core surrounded by a loose mantle of a cells and occasional d cells. pp c ... | 1985 | 3913912 |
| seasonal cycles in testicular activity, gonadotropin, and thyroxine in the painted turtle, chrysemys picta, under natural conditions. | plasma levels of testosterone (t), thyroxine (t4) and follicle-stimulating hormone (fsh) were measured in a field population of the painted turtle, chrysemys picta, in michigan. all three hormones showed pronounced seasonality; plasma luteinizing hormone (lh) remained nondetectable. plasma t and fsh concentrations were highly correlated and exhibited biphasic cycles with peaks in spring and fall, whereas t4 showed a single peak in summer, coincident with the nadir in t. hormone levels were minim ... | 1985 | 3926601 |
| in vivo and in vitro responses to gonadotropin releasing hormone in the turtle, chrysemys picta, in relation to sex and reproductive stage. | in vivo and in vitro responsiveness to gonadotropin releasing hormone (gnrh) was studied in the turtle, chrysemys picta, after manipulation of reproductive condition by temperature: warm temperatures (28 degrees) induced testicular growth and ovarian regression compared to cold (17 degrees) treatment. only males (and primarily from cold treatment) responded to gnrh injection (40 micrograms/100 g body wt intracardiac); correlated increases occurred in plasma lh and testosterone. effects of gnrh ( ... | 1985 | 3932124 |
| immune response in the turtle (chrysemys picta). | 1972 | 4114647 | |
| morphological organization of monoamine-containing neurons in the hypothalamus of the painted turtle (chrysemys picta). | 1974 | 4132970 | |
| adenosine triphosphatase activity within heart homogenates of the turtle, chrysemys picta. | 1967 | 4226744 | |
| adenosine triphosphatase activity of heart mitochondria of the turtle, chrysemys picta. | 1970 | 4249480 | |
| the effects of induced cold torpor on atpase activity of the turtle, pseudemys (chrysemys) picta. | 1972 | 4260488 | |
| behavior of the turtle (chrysemys picta picta) in simultaneous, successive, and behavioral contrast situations. | 1974 | 4412173 | |
| the origin and distribution of catecholaminergic axon terminals in the cerebral cortex of the turtle (chrysemys picta). | 1974 | 4423150 | |
| effect of hypophysectomy on renal function in the western painted turtle (chrysemys picta belli). | 2015 | 4649159 | |
| behavioral visual functions for chrysemys picta picta. preferences and frequency responses. | 1972 | 4653341 | |
| effects of cold exposure on cardiac metabolism of the turtle pseudemys (chrysemys) picta. | 1973 | 4686499 | |
| distribution of monoamine-containing nerve terminals in the brain of the painted turtle, chrysemys picta. | 1973 | 4700507 | |
| demonstration of a catecholaminergic pathway from the midbrain to the strio-amygdaloid complex in the turtle (chrysemys picta). | 1973 | 4716140 | |
| de lange characteristics for the fresh-water turtle chrysemys picta picta, and the pigeon columba livia. | 1973 | 4746984 | |
| normal embryonic stages of the western painted turtle, chrysemys picta bellii. | 1973 | 4753442 | |
| antidiuretic effect of arginine vasotocin in the western painted turtle (chrysemys picta belli). | 1972 | 5009670 | |
| steroid biosynthesis by painted turtle (chrysemys picta picta) adrenals. | 1972 | 5021414 | |
| ionoregulatory responses of the hypophysectomized turtle chrysemys picta to osmotic stresses. | 1971 | 5128299 | |
| a structural and functional analysis of walking in the turtle, chrysemys picta marginata. | 1971 | 5135653 | |
| occurrence and distribution of monoamine-containing neurons in the brain of the painted turtle, chrysemys picta. | 1971 | 5140519 | |
| behavior of the aquatic turtle (chrysemys picta) on a modified visual cliff. | 1971 | 5159009 | |
| adrenalectomy of the painted turtle (chrysemis picta belli): effect on lonoregulation and tissue glycogen. | 1970 | 5423002 | |
| life cycle and pathology of spirorchis scripta stunkard, 1923 (digenea: spirorchiidae) in chrysemys picta picta. | 1968 | 5647114 |