| amphibian carbonic anhydrase: purification and partial characterization of the enzyme from erythrocytes of rana catesbeiana. | | 1976 | 9262 |
| effects of stereochemical structures of tetrahydrobiopterin on tyrosine hydroxylase. | 1. four stereochemical isomers of tetrahydrobiopterin, i.e., 6-l-erythro-, 6-d-erythro-, 6-l-threo-, or 6-d-threo-1,2-dihydroxypropyltetrahydropterin, have been synthesized and used as cofactors for tyrosine hydroxylase (ec 1.14.18.-) purified from the soluble fraction of bovine adrenal medulla. the l-erythro- (the putative natural cofactor) and d-threo isomers showed a striking similarity in their cofactor activities for tyrosine hydroxylase; the remaining two isomeric tetrahydrobiopterins, d-e ... | 1977 | 12820 |
| isolation and partial characterization of the serum low density lipoprotein from bullfrog, rana catesbeiana. | the chemical and physical properties of bullfrog serum low density lipoprotein (ldl) were investigated. on a weight percentage basis, ldl contained cholesterol ester, 30.3%; cholesterol, 5.6%; triglyceride, 12.5%; phospholipids, 23.3%; and protein, 22.4%. the fatty acid compositions of triglycerides and major phospholipids from the bullfrog serum ldl were quite similar to those of human serum ldl. however, the fatty acid composition of the chlesterol ester from the bullfrog serum ldl was quite d ... | 1977 | 19427 |
| antisecretory effect of imidazole and its derivatives in an isolated gastric mucosa preparation and an anesthetized young chicken preparation; comparison with a histamine h2-receptor antagonist. | we invesigated the influences of imidazole on the basal and the secretagogue-stimulated gastric acid secretion in isolated bullfrog gastric mucosa preparations and in anesthetized young chickens. imidazoles (1 x 10(-4) g/ml) readily depressed the basal acid secretion in gastric mucosa in vitro. the inhibitory effect of imidazole was diminished considerably after washing out of the drug. the maximum acid secretion elicited by tetragastrin or bethanechol was completely antagonized by imidazole (1 ... | 1978 | 29155 |
| isolation and preliminary characterization of two varieties of low molecular weight immunoglobulin in the bullfrog, rana catesbeiana. | two varieties of low m.w. immunoglobulins have been isolated from the serum of rana catesbeiana frogs. they are highly cross-reactive, although each also contains unique antigenic determinants. since both low m.w. immunoglobulins were identified in the serum of 22 individual frogs, it was concluded that they are isotypic variants. the light chains of r. catesbeiana and mammalian high and low m.w. immunoglobulins are similar in electrophoretic mobility on polyacrylamide gels containing sodium dod ... | 1976 | 59776 |
| humoral immune responses in rana catesbiana frogs and tadpoles. | rana catesbiana adult frogs and tadpoles were immunized with the bacteriophage f2, 0x-174, and t4 and the haptens 2,4 dinitrophenyl (dnp) and fluorescein (ftc). the haptens were conjugated with bovine serum albumin (bsa), bovine gamma globulin (bgg), or horsehoe crab hemocyanin (hycn). sera were obtained from immunized animals at invervals up to six months after immunization. the antibody activities were measured by bacteriophage neutralization techniques. sucrose density gradients were used to ... | 1976 | 59790 |
| comparison of the temperature-dependence of rapid axonal transport and microtubules in nerves of the rabbit and bullfrog. | 1. the average velocity of transport of dopamine-beta-hydroxylase, an enzyme confined to unmyelinated adrenergic nerves, was measured in rabbit and bullfrog sciatic nerves or branches incubated in vitro at various temperatures. in parallel experiments, the number and density of microtubules were measured in cross-sections of randomly selected unmyelinated axons from another set of nerves incubated under the same conditions. 2. average transport velocity was exponentially related to temperature o ... | 1979 | 85705 |
| plasma thyroxine and triiodothyronine levels in spontaneously metamorphosing rana catesbeiana tadpoles and in adult anuran amphibia. | we have developed sensitive and reliable radioimmunoassays for t4 and t3 in amphibian plasma and have used these procedures to measure plasma t4 and t3 levels in spontaneously developing rana catesbeiana tadpoles at various stages of metamorphosis. during premetamorphosis circulating levels of both t4 and t3 were below the limits of detection of the ria procedures (t4 less than 50 ng/100 ml, t3 less than 5 ng/100 ml). a gradual rise in plasma t3 and t4 became apparent during prometamorphosis, an ... | 1978 | 105869 |
| effects of beta-(p-chlorophenyl)-gaba (baclofen) on spinal synaptic activity. | in the isolated perfused spinal cord of the bullfrog, baclofen caused a reduction in the rate of spontaneous discharges in the ventral root at lower concentrations than gaba. the inhibitory effect of baclofen was fully present in a chloride-free medium, whereas that of gaba was markedly reduced. in contrast to gaba, which depolarized the dorsal root, baclofen produced a hyperpolarization in the dorsal root. moreover, baclofen produced a hyperpolarization in the ventral roots. in the rat, the dev ... | 1977 | 142012 |
| light and electron microscopic investigation of atpase activity in musculature during anuran tail resorption. | the histochemical activity of adenosine triphosphatase (atpase) was studied at light and electron microscopic levels in larval tail musculature of rana catesbeiana and rana ornativentris during late metamorphic stages. the presence of low, moderate or dark reaction of k2-edta-preincubated ca++-atpase was correlated with the variable degree of degeneration of white fibres even at the late stage of tail resorption. the reasons for an increase in this atpase activity in degenerating white muscle fi ... | 1978 | 153341 |
| a kinetic analysis of the cyclic nucleotide phosphodiesterase regulation by the endogenous protein activator. a study of rat brain and frog sympathetic chain. | the effect of the endogenous protein activator on the kinetic characteristics of a highly purified, activator-deficient rat brain phosphodiesterase (ec 3.1.4.-) of a highly purified, activator-deficient rat brain phosphodiesterase (ec 3.1.4-) was studied. this enzyme preparation has only a high km for cyclic amp and a low km for cyclic gmp. in the presence of 20 mum ca2+, saturating concentrations of the activator decreased the km of this enzyme for cyclic amp from 350 mum to about 80 mum, witho ... | 1976 | 174744 |
| cyclic gmp modulates the intensity of post-tetanic potentiation in bullfrog sympathetic ganglia. | | 1976 | 176609 |
| studies on the comparative pharmacology and selective toxicity of tricaine methanesulfonate: metabolism as a basis of the selective toxicity in poikilotherms. | tricaine methanesulfonate, administered at a dose of 150 mg/kg i.p., produced a flaccid paralysis and loss of the righting reflex in a number of poikilothermic species including the frog. leopard frogs (rana pipiens) given 150 mg/kg i.p. regained the righting reflex at 113 +/- 28 (s.d.) minutes after injection. a similar dose administered i.p. to mice produced no apparent pharmacological response. the biological half-life (t1/2) of tricaine in frogs (r. pipiens) was about 70 minutes at temperatu ... | 1976 | 185356 |
| synaptic potentials in sympathetic ganglia: are they mediated by cyclic nucleotides? | the hypothesis that cyclic nucleotides are intracellular second messengers mediating the generation of synaptic potentials was studied in the sympathetic ganglia of the bullfrog. synaptic potentials and the effect of administering cyclic nucleotides and agents which affect cyclic nucleotide metabolism were recorded by the sucrose gap technique. the administration of adenosine 3',5'-monophosphate (cyclic amp), guanosine 3',5'-monophosphate (cyclic gmp), or several of their derivatives produced li ... | 1978 | 206964 |
| mercaptoimidazolylpropionic acid hydrobromide. inhibition of tadpole collagenase and related properties. | a mercapto analogue of histidine (1), (rs)-2-mercapto-3-(5-imidazolyl)propionic acid (2), was prepared by treatment of (rs)-2-bromo-3-(5-imidazolyl)propionic acid with trithiocarbonate. decomposition of the resulting intermediate with hydrochloric acid followed by sephadex g-15 chromatography permitted isolation of 2 as a hydrobromide complex having unusual stability and properties as evidenced by ir and 1h nmr data. the potency of this complex in inhibiting tissue (rana catesbiana) collagenase ... | 1978 | 209189 |
| cell-free translation and thyroxine induction of carbamyl phosphate synthetase i messenger rna in tadpole liver. | total rna of tadpole and frog (rana catesbeiana) liver was isolated by either 7 or 8 m guanidine . hcl extraction and translated in a cell-free protein-synthesizing system derived from rabbit reticulocytes. the identity of carbamyl phosphate synthetase i[carbamoyl-phosphate synthase (ammonia); atp:carbamate phosphotransferase (dephosphorylating), ec 2.7.2.5] synthesized in vitro with the purified enzyme was established as follows: (i) immunoprecipitation by a specific antibody; (i) comigration w ... | 1979 | 226957 |
| preferential binding of tri-substituted thyronine analogs by bullfrog tadpole tail fin cytosol. | the relative strength of binding of several triiodothyronine (t3) analogs by cytosol prepared from the tail fin of the bullfrog tadpole has been tested and compared with their thyromimetic activity in tail tissue. in competitive binding experiments, four tri-substituted analogs were bound much more strongly than two tetra-derivatives. correlation between binding and relative thyromimetic activity was observed only for three triiodo-substituted compounds, triiodothyronine, its methylene bridge an ... | 1977 | 299742 |
| mucus clearance: in vivo canine tracheal vs. in vitro bullfrog palate studies. | tracheal mucociliary clearance was studied by a radioisotope technique in pentothal-anesthetized beagles in the control, atropinized, or dehydrated state. mucus collected from a tracheal pouch in each dog was used for in vitro bullfrog (rana cantesbiana) palate clearance studies and compared to the in vivo clearance rates. in all three experimental states, there was a significant correlation between in vivo and in vitro rates, suggesting that tracheal pouch mucus is a good model for investigatin ... | 1977 | 301138 |
| effects of antisera to bullfrog prolactin and growth hormone on metamorphosis of rana catesbeiana tadpoles. | | 1977 | 301839 |
| biological activity of bullfrog growth hormone in the rat and the bullfrog (rana catesbeiana). | highly purified bullfrog growth hormone (gh) was tested for growth promoting activity in rats and bullfrogs (rana catesbeiana). in repeated assays, the potency of bullfrog gh in the rat tibia assay was 1 x bovine gh, which is significantly greater than all other non-mammalian ghs tested. it also stimulated significant whole body growth in immature hypophysectomized rats injected daily for 16 days. in bullfrogs, the bullfrog gh (about 2 microgram/injection) stimulated growth and appetite in intac ... | 1977 | 302789 |
| cytoarchitectonic analysis of the bullfrog (rana catesbeiana) spinal cord by means of electron microscopy with special reference to distribution of microneurons. | in order to determine cytological nature of the "small cells" found in the dorsal half of the bullfrog spinal cord at the electron microscopic level, the complete mapping of these elements was carried out, using both paraffin and thick sections. as a result, these elements were demonstrated to have four main fine structural characteristics of an unequivocally neuronal nature: (1) synaptic contacts, (2) subsurface cisternae, (3) typical pattern of the rough-surfaced endoplasmic reticulum, and (4) ... | 1977 | 302841 |
| in vitro stimulationof 5 alpha-dihydrotestosterone and testosterone secretion from bullfrog testis by nonmammalian and mammalian gonadotropins. | | 1977 | 303584 |
| membrane currents underlying activity in frog sinus venosus. | 1. the spontaneous electrical activity of small strips of muscle from the sinus venosus region of the heart of rana catesbeiana was investigated using the double sucrose gap technique. the voltage clamp was used to record the ionic currents underlying the pace-maker depolarization and the action potential.2. the records of spontaneous electrical activity are very similar to those obtained from the sinus venosus using micro-electrodes. moreover, the pace-maker activity is almost completely insens ... | 1977 | 303699 |
| the induction of ferritin synthesis in circulating larval red blood cells. | the circulating red blood cells formed in bullfrog larvae, chicken embryos, and mouse embryos contain large amounts of ferritin and storage iron in excess of the need for hemoglobin. in contrast, the circulating red cells of adult animals contain little ferritin. ferritin synthesis and iron storage are coordinated with differentiation and hemoglobin synthesis in the red cells of adults. in order to test the hypothesis that ferritin synthesis could be controlled independently of hemoglobin synthe ... | 1978 | 305918 |
| supravital excitability of skeletal muscle of rats and bullfrogs to electrical stimuli. | supravital excitability to electrical stimuli (for convenience, supravital electrocontractility (s.ec) of the gastrocnemius muscle of rats and bullfrogs was examined after "somatic death" and the time during which s.ec could be detected (s.ec duration) was measured. s.ec of the gastrocnemius muscle of rats and bullfrogs depended on temperature. the maximum s.ec duration of the muscle of rats and bullfrogs were 110 min and 96 hr, respectively, at a low temperature (5 degrees), and 60 min and 9 hr ... | 1978 | 306897 |
| initial observations on the isolated retinal pigment epithelium-choroid of the cat. | an in vitro preparation of a mammalian retinal pigment epithelium (rpe)-choroid was developed, that of the cat, in order to study the rpe in isolation from the neural retina. the purpose of these initial experiments was to evaluate the electrical characteristics of the tissue and the ionic properties of the rpe apical membrane. they were designed so that results would be directly comparable to those previously obtained on a more extensively studied cold-blooded preparation, the bullfrog. the ele ... | 1978 | 307543 |
| natural hemolytic activity of snake serum. ii. heterogeneity of putative natural antibody and levels of hemolytic activity. | the erythrocytes of various vertebrates, such as mice, rabbits, sheep, chickens, bullfrogs, and toads are lysed by normal snake sera. however, snake erythrocytes were not lysed by serum from different snake species. putative natural antibody seems with different specificities to comprise heterogeneous antibodies. thus, absorption of snake serum with mouse erythrocytes, for example, abrogated hemolytic activity for mice but not for rabbit or sheep erythrocytes. we observed no significant intraspe ... | 1978 | 308470 |
| glomerular permeability in the bullfrog rana catesbeiana. | filtration studies suggest similar size pores in the glomerular filters of mammals and amphibians. however, the glomerular wall in the bullfrog exhibits several structural features not found in mammals. the subendothelial space of the basement membrane is often greatly enlarged and infiltrated by cellular elements. the lamina densa of the basement membrane shows extensive variation in thickness and packing of its filaments. on the other hand, the epithelial slits in the bullfrog are closed by a ... | 1978 | 309886 |
| an o2-hb "paradox' in frog blood? (n-values exceeding 4.0). | o2-hb dissociation curves have been determined for the anurans, rana temporaria and rana catesbeiana, and compared with human blood for the specific purpose of defining the n-value (hill's cooperativity coefficient) at high o2 saturations. the p50 values at normal conditions (see fig. 1) for each species were 24.6 mm hg for human blood, 37.0 mm hg for rana temporaria blood and 53.5 mm hg for rana catesbeiana. for human blood the n-value was 2.7 at saturations from 36% to 98% levelling off at the ... | 1978 | 311071 |
| experimental allergic neuritis in the lewis rat. | purified myelin from the peripheral nervous system of guinea pig, frog (rana catesbeiana), rat, rabbit, beef, and human in freund's adjuvant were injected into the lewis rat. groups of rats receiving injections of myelin from different species were examined for signs of dysfunction and lesions in the pns and cns. injection of frog pns myelin into the lewis rat did not produce any clinical signs or lesions typical of experimental allergic neuritis (ean) or experimental allergic encephalomyelitis ... | 1979 | 312920 |
| effect of exogenous thyroxine on plasma retinol-binding protein of tadpole (rana catesbeiana) with special reference to affinity for human prealbumin. | | 1979 | 312924 |
| liver ribonucleases from the bullfrog, rana catesbeiana. purification, properties and changes in activity during metamorphosis. | a major and three minor rnaases exhibiting activity at neutral ph were found in bullfrog liver homogenates. these rnaases were purified to electrophoretic homogeneity. total purification was 1100 to 1600-fold, and the average recovery was 35%. the molecular weight estimated by gel filtration and sds-urea-polyacrylamide gel electrophoresis was 12,000 for all the components. an antibody against the major rnaase (component b) reacted with the major rnaase to form a single precipitin line on double ... | 1979 | 313217 |
| inhibitory effect of cimetidine, an antagonist of histamine h2-receptor, on gastric acid secretion in isolated frog stomach and in anesthetized young chicken. | gastric antisecretory effect of a new histamine h2-receptor antagonist, n"-cyano-n-methyl-n'-[2-t5-methyl-imidazol-4-yl)-methylthioethyl]guanidine (cimetidine), was studied in isolated bullfrog gastric mucosa and in anesthetized young chicken preparation with acute gastric fistulae. cimetidine inhibited dose-dependently the secretory responses of frog gastric mucosa to histamine, and parallel shift of the concentration-response curve of histamine by cimetidine indicated the competitive character ... | 1978 | 314297 |
| fine structural distribution of the surface-connected canalicular system in frog thrombocytes. | the existence of the surface-connected canalicular system (sccs) has been demonstrated in semithick sections of the frog thrombocytes by the use of a high voltage electron microscope. the sccs of the thrombocytes in rana catesbeiana and rana nigromaculata consists of numerous canaliculi and vesicles with a diameter of 250 nm, which join with one another to make a complex network throughout the cytoplasm. although the sccs of xenopus laevis fits well into the pattern described in rana catebeiana, ... | 1979 | 315820 |
| inhibition of thyroxine-induced metamorphosis by prolactin in tadpoles, rana catesbeiana. | thyroxine (t4)-prolactin interactions on hepatic arginase and ornithine transcarbamylase (otc) as well as hind legs, tail, digestive tract and median eminence were investigated in tadpoles, rana catesbeiana. prolactin completely blocked t4-induced tail resorption, but failed to suppress hind-leg growth, shortening of digestive tract and promotion by t4 of the median eminence development. prolactin blocked t4-induced increase in hepatic arginase activity but not in hepatic otc activity. a possibi ... | 1979 | 316768 |
| structural studies of natural actomyosin from thermally acclimated frogs. | natural actomyosin was isolated from skeletal muscle of frogs (rana catesbeiana) acclimated at 25 degrees c and 5 degrees c. it was found that preparations isolated from warm-acclimated frogs may display considerable degradation of myosin heavy chains as compared with preparations isolated from cold-acclimated frogs. however, degradation may be minimized by inclusion of protease inhibitors during purification, indicating enhanced protease activity in preparations of natural actomyosin from warm- ... | 1979 | 317357 |
| effect of nondialyzable solids concentration and viscoelasticity on ciliary transport of tracheal mucus. | the viscoelastic properties of reconstituted canine tracheal mucus were correlated with the ciliary transport rate measured on the bullfrog palate. a maximum in mucociliary transport rate was found at an optimal concentration of nondialyzable solids of 1.5 to 2 per cent. at concentrations less than this value, the mucus had little or no elasticity and low rates of transport; at concentrations greater than the optimum, however, further increases in elastic modulus also resulted in decreasing tran ... | 1977 | 318052 |
| distribution of carbonic anhydrase within the gastric mucosa. | bullfrog fundic mucosa was separated into fractions containing predominantly surface epithelial cells, mucous neck cells, and and oxyntic cells, respectively, and the carbonic anhydrase concentration of each fraction and of antral mucosa was measured. there were no significant differences between the enzyme concentrations of these fractions. the mean level was 12.4 units of activity per milligram of protein. the cellular localization of carbonic anhydrase in the gastric fundic and antral mucosa ... | 1977 | 403105 |
| immunochemical studies on the pituitary gonadotropins (fsh and lh) from the bullfrog, rana catesbeiana. | | 1977 | 408225 |
| intermittent flow in tendon capillary bundles. | the capillary bed has been observed in the achilles tendon of 40 bullfrogs and 10 guinea pigs for periods of up to 2 h. the opening and closing of adjacent capillaries in a perfused area follows the pattern originally described by krogh for skeletal muscle but the frequency is slower, as anticipated from the lower metabolic rate of tendon. however, superimposed on this "flickering is a much slower process whereby whole bundles of 20-147 capillaries open and close with little overlap in the tissu ... | 1979 | 457548 |
| species-specific effects on the optical signals of voltage-sensitive dyes. | the absorption changes of two merocyanine dyes in response to membrane potential changes were measured on several neuronal preparations to see whether the dyes would be useful in recording from these cells. we were able to record large signals without averaging from barnacle and leech neurons. the greatest signal with ww375 was seen at 750 nm. much smaller increases in transmitted light intensity were seen at all other wavelengths between 500 and 780 nm. in contrast, vertebrate neuronal preparat ... | 1979 | 490629 |
| vitamin a transport in plasma of the non-mammalian vertebrates: isolation and partial characterization of piscine retinol-binding protein. | studies were conducted to explore vitamin a transport in the non-mammalian vertebrates, especially pisces, amphibia, and reptilia, and to isolate and partially characterize piscine retinol-binding protein. retinol-containing proteins in fresh plasma obtained from bullfrogs and a turtle exhibited similar properties to those found in mammalian and chicken plasma: i.e., molecular weight of about 60,000-80,000 as estimated by gel filtration and binding affinity to prealbumin on human prealbumin-seph ... | 1977 | 562910 |
| cyclic polyether-protonated organic amine binding: significance in enzymatic and ion transport processes. | the cyclic polyether, 18-crown-6, reacts with protonated amines in methanol to form complexes whose formation constants (log k) decrease in the order nh4+, rnh3+ greater than r2nh2+ greater than r3nh+. in the case of the organic amines, this stability order is identical to the earlier observed permeability sequence for protonated organic amines in glyceryl dioleate bilayers treated with valinomycin, nonactin, or gramicidin, and in bullfrog and rabbit gallbladder membranes. the decrease in log k ... | 1978 | 622582 |
| the permeability of the secretin stimulated exocrine pancreas to non-electrolytes. | 1. a method of measuring the permeability of the pancreas by determining the apparent reflexion coefficient (sigmaa) is described, in the isolated pancreas secreting maximally under the influence of secretin. the principle is to add a non-electrolyte to the perfusate which will create an osmotic gradient (rtsigmadeltac) counter to that of active transport and reduce the secretion rate. this is compared with the effect of an equal concentration (0.1 m) of sucrose (rtdeltac; sigma = 1). the appare ... | 1978 | 650509 |
| immunoglobulins in ranid frogs and tadpoles. | three distinct immunoglobulins (igs) have been isolated from serum of rana catesbeiana frogs. one of these is high in molecular weight and probably corresponds to the igm-like igs that have been isolated from a variety of vertebrate species. the other 2 igs are lower in molecular weight (approximately 7s) and very similar in subunit structure. they were highly cross-reactive, although each contained unique antigenic determinants. their relationship to other vertebrate ig classes remains to be es ... | 1975 | 812343 |
| purification and properties of reptilian and amphibian growth hormones. | highly purified growth hormone was isolated from the pituitaries of two reptilian species, the snapping turtle and the sea turtle, and two amphibian species, the bullfrog and the leopard frog. characterization studies were performed with these growth hormones in comparison with mammalian and avian growth hormones. great similarities among these species were found in chromatographic behavior, ve/vo ratios (2.0) on gel filtration, disc electrophoretic patterns, terminal amino acid residues and imm ... | 1976 | 821743 |
| absence of high-affinity low-capacity components of t4-binding sites in the cytosol of the bullfrog tadpole. | | 1976 | 821811 |
| failure of a cell-free system from rabbit reticulocytes to remove iron from transferrin. | 1. cell-free solutions prepared from rabbit reticulocytes were not able to release iron from rabbit transferrin. 2. the results, which differ from those obtained with rana catesbeiana immature erythrocytes, indicate that cellular integrity is a requirement for this process in the rabbit reticulocyte system. | 1976 | 985442 |
| effects of parasitism by the lung fluke, haematoloechus medioplexus, on lung fatty acid and sterol composition in the bullfrog, rana catesbiana. | | 1975 | 1078814 |
| coelomic fluid and blood serum proteins of the metamorphosing bullfrog tadpole. | bullfrog (rana catesbeiana) tadpoles were divided into four groups containing gosner ('60) stages as follows: i, 27-31; ii, 32-36; iii, 37-41; iv, 42-46. extractable coelomic fluid volume from late metamorphic tadpoles (group iv) was found to have a highly significant (p less than 0.001) negative correlation with stage; tadpole weight also had a negative correlation with stage (p less than 0.025). no significant correlation was found between coelomic fluid volume and tadpole weight. group iv blo ... | 1975 | 1080793 |
| binding by thyroid hormones by nuclei of cells from bullfrog tadpole tail fins. | the regression of the tadpole tail is under the direct control of the thyroid hormones and offers a unique system for the study of the action of these hormones. we have examined the binding of l-triiodothyronine (t3) and l-thyroxine (t4) in vitro using tail fin bricks which included epidermal and connective cells. the binding of 125i-labeled hormones was followed in both nuclear and extranuclear fractions. high affinity and limited capacity sites for t3 and t4 were observed only for the nuclear ... | 1975 | 1081450 |
| binding of thyroxine and triiodothyronine by nuclei of isolated tadpole liver cells. | the binding of l-triiodothyronine (t3) and l-thyroxine (t4) to cytoplasm and nuclei has been studied in isolated rana catesbeiana tadpole liver cells. nuclear binding for both thyroid hormones occurred more slowly at 4 c than at 25 c, but reached the same level as at 25 s. scatchard analyses suggest high affinity, saturable binding sites for both hormones in the nuclear but not in the cytoplasmic fraction. apparent equilibrium dissociation constants were 6.8 x 10(-10)m and 4.6 x 10(-10)m for t3 ... | 1975 | 1081451 |
| difference in calcium content of atrial and ventricular muscle. | the calcium content and inulin space of the atrial and ventricular muscle were determined in isolated perfused heart of the toad, bullfrog, guinea pig, rat, and cat. in all species studied, the total and "cellular" calcium content of the atrium were higher than those of the ventricle. a high calcium content of the atrial muscle was also observed in fresh unperfused hearts. the total calcium content of atrial and ventricular muscles increased when extracellular phosphate concentration was increas ... | 1975 | 1082044 |
| isolation and characterization of luteinizing hormone from amphibian (rana catesbeiana) pituitaries. | | 1976 | 1082969 |
| architecture of the marrow vasculature in three amphibian species and its significance in hematopoietic development. | architecture of the bone marrow vasculature, particularly that of the femur, was analyzed in three amphibian species in relation to the early phylogeny of marrow hematopoiesis. a dye-injection method and histological techniques, including both serial sectioning and reconstruction methods, were used for this purpose. from these observations the following conclusions may be drawn. (1) marrow hematopoiesis is absent from the femur of the urodelan (triturus pyrrhogaster) and appears first in the fem ... | 1976 | 1083670 |
| alpha-galactosyltransferase activity in the serum of frogs (rana catesbeiana). | human blood group 0 cells were converted into b-active cells by incubation with uridine diphosphate d-galactose and unfractionated serum from bull frog (rana catesbeiana). under these conditions, "bombay" (oh) type red cells were not converted, and group 0 foetal cells possessing a few h antigenic sites were only weakly converted into b-active cells. in addition, the agglutination titer of the converted cells with anti-h serum decreased. these results therefore indicate that the conversion depen ... | 1976 | 1087514 |
| comparison of amphibian whole-cell and cell-free activity towards different transferrins. | 1. a cell-free preparation from immature-erythrocytes of the bullfrog (rana catesbeiana) was about equally active towards iron bound to homologous, rabbit or human transferrin. 2. in contrast with the cell-free system, whole immature erythrocytes exhibited optimum, intermediate or low uptake of iron from the above and from other transferrins. | 1976 | 1087558 |
| mitotic variations in the lens epithelium of the frog iv. studies with isolated anuran pituitary factors. | proteins corresponding to growth hormone and prolactin have been electrophoretically separated from the pituitary gland of the frog (rana pipiens berlandieri and rana catesbeiana). these substances can independently stimulate mitosis in the lenses of animals where it had previously been inhibited by means of hypophysectomy. dna synthesis is greatly augmented six days after the start of hormone administration to intact animals. nine days are required before this occurs in hypophysectomized ones. ... | 1976 | 1087617 |
| blockage of gallbladder tight junction cation-selective channels by 2,4,6-triaminopyrimidinium (tap). | the organic cation 2,4,6-triaminopyrimidinium (tap) specifically inhibits na+ passive permeation (pna) across gallbladder, small intestine, and choroid plexus without detectable effect on the cl(-) permeability, indicating that na+ and cl(-) follow different permeation pathways. in bullfrog gallbladder, where it was examined in greater detail, the effect of tap was shown to be: (a) completely reversible, (b) due only to the protonated form of 2,4,6-triaminopyrimidine, (c) effective when added to ... | 1975 | 1159404 |
| the abundance of ferritin in yolk-sac derived red blood cells of the embryonic mouse. | circulating red blood cells formed early in development have several distinctive properties which include retention of the nucleus (mammals), large size and characteristic haemoglobin type (mammals, birds, amphibia). the primitive or embryonic red cells of early development are replaced by the definitive red cells which contain fetal or adult haemoglobin; a second developmental change occurs in the haemoglobin of some mammals (man, cattle, sheep) but does not involve a cell replacement. circulat ... | 1976 | 1276087 |
| sequential up-regulation of thyroid hormone beta receptor, ornithine transcarbamylase, and carbamyl phosphate synthetase mrnas in the liver of rana catesbeiana tadpoles during spontaneous and thyroid hormone-induced metamorphosis. | during both spontaneous and thyroid hormone (th)-induced metamorphosis, the rana catesbeiana tadpole undergoes postembryonic developmental changes in its liver which are necessary for its transition from an ammonotelic larva to a ureotelic adult. although this transition ultimately results from marked increases in the activities and/or de novo synthesis of the urea cycle enzymes, the precise molecular means by which th exerts this tissue-specific response are presently unknown. recent reports, u ... | 1992 | 1291156 |
| preparation and characterization of troponin c from bullfrog skeletal muscle. | troponin c was isolated from the skeletal muscle of bullfrog (rana catesbeiana), and its relative molecular mass was estimated to be 18,000 by sds/polyacrylamide gel electrophoresis. in its amino acid composition, bullfrog troponin c was similar to that of the frog (rana esculenta) but different from that of rabbit. its ultraviolet spectrum was consistent with its amino acid composition. the ultraviolet difference spectrum of the ca(2+)-loaded form vs. the metal-free form indicated that the sing ... | 1992 | 1295889 |
| possible role of red cell deformability and microvasculature in microcirculation. | the roles of the deformability of red blood cells (rbc) and the microvasculature in the maintenance of blood flow were investigated in terms of the pressure (p)-flow rate (q) relationships in human rbc suspension perfusions of bullfrog hind limb. although isotonicity for the bullfrog is approximately 215 mosm/kgh2o, perfusions in intact hind limbs showed no change in the p-q relationship at test solution osmolalities ranging from approximately 150 to approximately 300 mosm/kgh2o. the deformabili ... | 1992 | 1297857 |
| heterogeneity of the retinal g-protein transducin from frog rod photoreceptors. biochemical identification and characterization of new subunits. | transducin, a retinal g-protein, has been shown to exist as heterotrimers of alpha (39,000), beta (36,000), and gamma (approximately 7,000) subunits. blue sepharose cl-6b column chromatography of a transducin preparation extracted with a metal-free, low salt buffer containing gtp showed three distinct alpha and two distinct beta gamma activities in frog (rana catesbeiana) rod outer segment. the binding of a hydrolysis-resistant gtp analog in these alpha fractions was proportional to the amount o ... | 1992 | 1326554 |
| purification and characterization of joining peptide and n-terminal peptide of proopiomelanocortin from the pars distalis of the bullfrog pituitary. | the joining peptide (jp) and the n-terminal peptide of proopiomelanocortin (npp) were isolated from an acid-acetone extract of the distal lobe of the pituitary of the bullfrog, rana catesbeiana, and purified by gel filtration and reverse-phase high performance liquid chromatography. the amino acid sequence of the bullfrog jp resembled the sequences of the jps of rana ridibunda (86% similarity) and xenopus laevis (54% similarity), as deduced from the nucleotide sequences of their cdnas. the amino ... | 1992 | 1331997 |
| introduction of a disulfide bond into cytochrome c stabilizes a compact denatured state. | we introduced a novel disulfide bond, modeled on that of bullfrog cytochrome c, into yeast iso-1-cytochrome c. the disulfide spontaneously forms upon purification. a variety of techniques were used to examine the denaturation of this variant and several non-cross-linked controls. denaturation is reversible and, with the exception of the protein in which the two cysteines are blocked, consistent with a two-state process. comparison of the calorimetric and van't hoff enthalpy changes indicates tha ... | 1992 | 1334426 |
| purification and characterization of two ryanodine-binding protein isoforms from sarcoplasmic reticulum of bullfrog skeletal muscle. | the two ryanodine-binding proteins (rybps) have been purified from sarcoplasmic reticulum of bullfrog skeletal muscle by mono q column chromatography following solubilization of sr by chaps and sucrose density gradient centrifugation. we conclude that the two rybps (alpha- and beta-rybp) are isoforms on the basis (i) that each rybp is distinguished by a specific polyclonal antibody and (ii) that distinct polypeptides are generated by limited tryptic digestion of the two rybps. monomeric molecula ... | 1992 | 1337084 |
| calcium current modulation in frog sympathetic neurones: multiple neurotransmitters and g proteins. | 1. whole-cell calcium currents of bullfrog sympathetic neurones were partially inhibited by noradrenaline (na), chicken-ii-luteinizing hormone-releasing hormone (lhrh), muscarine, atp, substance p, or intracellular dialysis with guanosine 5'-o-(3-thiotriphosphate)(gtp-gamma-s) or aluminium fluoride. these agents had similar effects on the activation kinetics of calcium current. 2. the amplitude of the lhrh effect varied from cell to cell. this did not correlate with cell size or the time of whol ... | 1992 | 1357163 |
| calcium current modulation in frog sympathetic neurones: l-current is relatively insensitive to neurotransmitters. | 1. neurotransmitters (noradrenaline, na; chicken ii luteinizing hormone-releasing hormone, lhrh) and activators of g proteins (gtp-gamma-s and alf3) partially inhibit calcium current in bullfrog sympathetic neruones. activation of the remaining current is slowed and shifted to more positive voltages. 2. the n-type calcium current appears to be the type modulated, since approximately 90% of peak current is blocked by omega-conotoxin (omega cgtx) and modulation is not affected by nisoldipine. 3. c ... | 1992 | 1363436 |
| intracellular guanosine-5'-o-(2-thiodiphosphate) alters the dynamics of receptor-mediated responses in bullfrog sympathetic neurons. | the mechanism by which intracellularly applied guanosine-5'-o-(2-thiodiphosphate) alters responses to chicken ii luteinizing hormone-releasing hormone, muscarine, and substance p in bullfrog sympathetic neurons was examined. whole-cell recordings were made from enzymatically dissociated single neurons. guanosine-5'-o-(2-thiodiphosphate) was applied intracellularly by adding it to the pipette solution with fixed amounts of gtp. guanosine-5'-o-(2-thiodiphosphate) did not affect the proportion of c ... | 1992 | 1372087 |
| a pore transport model for pulmonary alveolar epithelium. | hydrodynamic heteropore flow models for transport of solutes across alveolar epithelial tissue have been developed. a two-size cylindrical pore model and a similar parallel-plate model were formulated, tested and used to predict effective pore sizes from literature data on transport in bullfrog, canine and rat lungs. the best fit equivalent pore-size estimates were obtained using a modified, nonlinear least squares procedure, with alveolar surface area to volume ratio (s/v) and small-pore area f ... | 1992 | 1380785 |
| trophic regulation of action potential in bullfrog sympathetic neurones. | these experiments tested the hypothesis that the normal electrophysiological properties of mature bullfrog sympathetic ganglion (bfsg) neurones are maintained by the retrograde supply of nerve growth factor-like molecules from peripheral target tissues. maintenance of these cells in explant culture in the absence of nerve growth factor (ngf) for up to 30 days produced electrophysiological changes that resemble those previously shown to accompany axotomy in vivo. these included (i) an increase in ... | 1992 | 1423027 |
| cytoplasmic localization of the dna virus frog erythrocytic virus. | in situ hybridization, using a biotinylated clone of frog erythrocytic virus (fev), was conducted to determine the location of viral sequences in bullfrog erythrocytes. fev-specific hybridization signals were found to correspond to mature cytoplasmic viral particles and assembly sites. these data are consistent with electron microscopic observations of viral assembly in the erythrocyte cytoplasm. although fev has morphological and biochemical properties similar to frog virus 3, our data suggest ... | 1992 | 1500276 |
| filtering properties of hair cells. | three questions were asked about filtering properties of hair cells. first, it was asked if hair cells in different receptors showed different filtering properties to match the receptor response to the particular characteristics of the stimulus? it seems that the answer is yes, since for example, the resonant frequencies of pigeon semicircular hair cells at membrane potentials around the rmp are in a range (12-280 hz) that could match angular head frequencies. since critical frequency tuning of ... | 1992 | 1599165 |
| immunocytochemical identification of growth hormone- and prolactin-producing cells in the hypophysis of the newt triturus cristatus carnifex laur. | single indirect immunocytochemical methods (immunofluorescence, pap, and abc) and double sequential staining (abc followed by immunofluorescence) were used to localize gh- and prl-producing cells in the pituitary distal lobe from triturus cristatus. the following antisera were employed: rabbit anti-ovine prl, anti-rana catesbeiana prl, anti-ovine gh, anti-bovine gh, and monkey anti-rat gh. a cell population corresponding to type-2 acidophils localized in the dorsal and central region, under the ... | 1992 | 1601268 |
| species differences in amphibian olfactory neuron reactivity to a monoclonal antibody. | a monoclonal antibody immunostained a subpopulation of olfactory sensory neurons in cryostat sections of the olfactory mucosa of the grass frog, rana pipiens, and the bullfrog, rana catesbeiana. however, in the olfactory tissues of the african clawed frog, xenopus laevis, only mucus and mucus-secreting components were stained, and no cell-specific immunoreactivity was seen in the tiger salamander, ambystoma tigrinum. this antibody is a useful marker of olfactory neuronal subpopulations in some a ... | 1992 | 1617462 |
| identification of cholecystokinin/gastrin peptides in frog and turtle. evidence that cholecystokinin is phylogenetically older than gastrin. | peptides homologous to mammalian cholecystokinin (cck) and gastrin in brain, antrum, and small intestine of an amphibian (the bullfrog, rana catesbeiana) and a reptile (the turtle, pseudomys scripta) were characterized. all tissues contained peptides reacting with antisera specific for the carboxyamidated c-terminal tetrapeptide common for cck and gastrin. extracts of all tissues, except the turtle antrum, also reacted with an antiserum specific for mammalian sulfated cck, while no extract conta ... | 1992 | 1633800 |
| mutagenesis of the iron-regulatory element further defines a role for rna secondary structure in the regulation of ferritin and transferrin receptor expression. | within the 5'-untranslated region of ferritin mrnas, there is a conserved region of 28 nucleotides (nt) (the iron regulatory element (ire)) that binds a protein (the ire-binding protein (ire-bp)) involved in the iron regulation of ferritin mrna translation. we have examined the role of rna secondary structure on the interaction of the ire with the ire-bp. first, the rat light ferritin ire possesses a structure similar to that of the bullfrog heavy ferritin ire (wang, y.-h., sczekan, s. r., and t ... | 1992 | 1644834 |
| regulation of c-erba-alpha messenger rna species in tadpole erythrocytes by thyroid hormone. | putative thyroid hormone (th) nuclear receptors have been detected in several tissues of rana catesbeiana tadpoles. t3 receptor number (sites per nucleus) in red blood cells (rbcs) and tail increases substantially just before metamorphic climax or in response to exogenous th; in contrast, receptor number in liver remains relatively constant. th receptors in mammals and birds are thought to be encoded by a c-erba gene. in the present study, two c-erba cdnas, one prepared from xenopus laevis oocyt ... | 1991 | 1645454 |
| inhibitions of acid secretion by e3810 and omeprazole, and their reversal by glutathione. | a substituted benzimidazole ([4-(3-methoxypropoxy)-3-methylpyridine-2-yl]methylsulfinyl)- 1h-benzimidazole sodium salt (e3810), is a gastric proton pump (h+, k(+)-atpase) inhibitor. e3810 and omeprazole inhibited acid accumulation dose dependently as measured with aminopyrine uptake in isolated rabbit gastric glands, their ic50 values being 0.16 and 0.36 microm, respectively. the addition of exogenous reduced glutathione (gsh) to the gland suspension reactivated dose dependently the acid secreti ... | 1991 | 1650210 |
| the 'lysine cluster' in the n-terminal region of na+/k(+)-atpase alpha-subunit is not involved in atpase activity. | the alpha-subunit of the na+/k(+)-atpases from several animal species have markedly similar amino acid sequences. however, the n-terminal sequences of the alpha-subunit are rather divergent except for lysine-rich sequences, the 'lysine cluster'. here we report that the alpha-subunit from frog (rana catesbeiana) has an n-terminal sequence with the 29 amino acid residues shorter than that of the xenopus alpha-subunit deduced from its cdna and hence lacks the 'lysine cluster'. nevertheless, the ran ... | 1991 | 1653015 |
| brain peptide yy receptors: highly conserved characteristics throughout vertebrate evolution. | we have shown previously that peptide yy (pyy) receptors are uniquely distributed in various mammalian brains and also have identified the receptor from porcine hippocampal membranes as a protein of 50,000 mol wt. to extend these observations, both the characteristics of pyy-receptor interaction and the structure of the receptor have been examined and compared with those of its sister peptide, neuropeptide y (npy), in the brains of various vertebrates including mammals (human, dog, guinea pig, r ... | 1991 | 1657579 |
| development of aldosterone-stimulation of short-circuit current across larval frog skin. | the short-circuit current (scc) across isolated skin from bullfrog larvae in developmental stage xxi was small and insensitive to amiloride. overnight incubation of this tissue with 10(-6) m aldosterone stimulated the scc from 1.35 +/- 0.55 to 14.55 +/- 4.12 microa.cm-2 with 11.18 +/- 4.46 microa.cm-2 being blocked by 100 microm amiloride. histologic examination of aldosterone-treated skins revealed a separation of the apical cell layer from the underlying epidermis that was not seen in untreate ... | 1991 | 1658089 |
| active transport of ascorbic acid across the retinal pigment epithelium of the bullfrog. | known functions of the rpe include glucose, water and retinoid transports; an ion transport mechanism utilizing a na(+)-k(+)-atpase pump located in the apical membrane has been proposed. recent studies with cultured rpe cells of cat and bovine indicate that the rpe takes up ascorbate by an active mechanism. in this study we use a mounted bullfrog rpe preparation to study unidirectional and net fluxes of radiolabeled (14c)-ascorbic acid (aa), (14c)-dehydroascorbic acid, (3h)-l-glucose(l-glu) and ... | 1991 | 1659972 |
| a model of a ca3 hippocampal pyramidal neuron incorporating voltage-clamp data on intrinsic conductances. | 1. we have developed a 19-compartment cable model of a guinea pig ca3 pyramidal neuron. each compartment is allowed to contain six active ionic conductances: gna, gca, gk(dr) (where dr stands for delayed rectifier), gk(a), gk(ahp), and gk(c). the conductance gca is of the high-voltage activated type. the model kinetics for the first five of these conductances incorporate voltage-clamp data obtained from isolated hippocampal pyramidal neurons. the kinetics of gk(c) are based on data from bullfrog ... | 1991 | 1663538 |
| phylogenetic study of serotonin-immunoreactive structures in the pancreas of various vertebrates. | the distribution pattern of serotonin (5ht) in the pancreas was studied immunohistochemically by using a 5ht monoclonal antibody in various vertebrates including the eel, bullfrog, south african clawed toad, turtle, chicken, mouse, rat, guinea-pig, cat, dog and human. in all species examined, except the bullfrog, 5ht-like immunoreactivity was observed in nerve fibers, in endocrine cells, or in both. positive nerve fibers were found in the eel, turtle, mouse, rat and guinea-pig. these fibers ran ... | 1991 | 1672509 |
| characterization of a novel le(x)-active ganglioside from chick intestinal tissues recognized by murine monoclonal antibody 188c1. | a monoclonal antibody, 188c1, raised against skin tissue from the back of bullfrogs (rana catesbeiana) was found to recognize a common antigen in neural and intestinal tissues of chicken (fujita, s. (1989) in biological transduction mechanisms (kasai, m., yoshioka, t., and suzuki, h., eds) pp. 159-177, japan scientific societies press, tokyo japan). the 188c1 antigen was isolated from chick intestinal tissues and characterized as a novel ganglioside by means of q-sepharose and iatrobeads column ... | 1991 | 1674743 |
| polymorphism in purified guanylate cyclase from vertebrate rod photoreceptors. | guanylate cyclase from rod photoreceptors of amphibian (toad, bufo marinus, and frog, rana catesbeiana) and bovine retinas was solubilized and purified by a single chromatography step on a gtp-agarose column. silver staining of purified amphibian enzymes in sds/polyacrylamide gels disclosed a doublet band (110 and 115 kda), while the bovine enzyme appeared as a singlet band (110 kda). the identification of these guanylate cyclases was confirmed using three chromatography systems with the purifie ... | 1991 | 1675787 |
| atp-activated channels in rat and bullfrog sensory neurons: concentration dependence and kinetics. | the concentration dependence and kinetics of ionic currents activated by extracellular adenosine 5'-triphosphate (atp) were studied in voltage-clamped dorsal root ganglion neurons from rats and bullfrogs. about 40% of neurons of both species responded to atp with an increase in membrane conductance. the atp-activated currents were similar in the 2 species, except that currents in rat neurons desensitized faster. in bullfrog neurons, the conductance was half-maximally activated by about 3 microm ... | 1990 | 1688928 |
| atp-activated channels in rat and bullfrog sensory neurons: current-voltage relation and single-channel behavior. | ionic currents activated by extracellular adenosine 5'-triphosphate (atp) were studied in voltage-clamped dorsal root ganglion neurons from rats and bullfrogs. under quasiphysiological ionic conditions, atp-activated current reversed near 0 mv and showed strong inward rectification. strong inward rectification was maintained even in symmetric solutions of divalent-free cs glutamate. examined with a resolution of 10s of microseconds, the rectification was instantaneous. inward current was greatly ... | 1990 | 1688930 |
| vaults. ii. ribonucleoprotein structures are highly conserved among higher and lower eukaryotes. | vaults are cytoplasmic ribonucleoprotein structures that display a complex morphology reminiscent of the multiple arches which form cathedral vaults, hence their name. previous studies on rat liver vaults (kedersha, n. l., and l. h. rome. 1986. j. cell biol. 103:699-709) have established that their composition is unlike that of any known class of rna-containing particles in that they contain multiple copies of a unique small rna and more than 50 copies of a single polypeptide of 104,000 mr. we n ... | 1990 | 1691193 |
| cloning and thyroid hormone regulation of albumin mrna in rana catesbeiana tadpole liver. | thyroid hormones are responsible for the specific biochemical and structural changes that occur during amphibian metamorphosis. in this study we screened a series of cdnas from a library constructed from t4-treated premetamorphic tadpole liver poly(a)+ rna in order to identify a clone that could be used to study the influence of t3 on liver-specific gene expression during rana catesbeiana metamorphosis. the cdna from one clone exhibited a greater degree of hybridization to liver rna from thyroid ... | 1990 | 1704484 |
| mechanism of modulation of gaba-activated current by internal calcium in rat central neurons. | gaba-activated currents in purkinje cells isolated from rat cerebellum were investigated. increase of intracellular ca2+ in the physiological range of concentrations caused a decrease in gaba-activated chloride currents. this effect resulted from a decrease of both the maximal values of gaba-activated currents and possibly from the affinity of gabaa receptors. therefore, the mechanism of ca2+ effect on gabaa receptors in central rat neurons differs from that in bullfrog sensory neurons. | 1991 | 1712659 |
| molecular cloning and expression of ferritin mrna in heavy metal-poisoned xenopus laevis cells. | in a search for genes transcriptionally regulated by metal ions, we have isolated a xenopus laevis ferritin cdna clone, xl2-17, from cadmium-poisoned xl2 cells. the large size of the corresponding ferritin mrna (1.4 kb) is due to the presence of a 629-nucleotide 5'-untranslated region. the xenopus ferritin sequence is highly isologous with other vertebrate ferritins. in particular, there is a complete sequence identity for the iron-responsive element (ire) located in the 5'-untranslated region i ... | 1991 | 1718317 |
| thalamic and midbrain auditory projections to the preoptic area and ventral hypothalamus in the green treefrog (hyla cinerea). | iontophoretic injections of horseradish peroxidase (hrp) into either the preoptic area or ventral hypothalamus of the green treefrog, (hyla cinerea), demonstrated inputs from thalamic and midbrain auditory nuclei. in a pattern similar to that seen in rana catesbeiana and rana pipiens, the central thalamic and secondary isthmal nuclei were found to provide heavy input to the ventral hypothalamus. additionally, a lighter input from the anterior thalamic nucleus was seen. in contrast, the preoptic ... | 1991 | 1764635 |
| acid proteinases of the fore-gut in metamorphosing tadpoles of rana catesbeiana. | 1. two types of acid proteinases were found in the adult stomach of the bullfrog, rana catesbeiana. 2. the first type of enzyme appeared in the developing stomach and esophagus and contained more than two kinds of acid proteinases. 3. these enzymes were identified as pepsin-type enzymes. 4. the second type of enzyme existed from the larva to adult stage and was also present in the adult duodenum. 5. this enzyme was different from pepsin and thought to be cathepsin e. | 1991 | 1769213 |
| differential appearance of the subunits of glycoprotein hormones (lh, fsh, and tsh) in the pituitary of bullfrog (rana catesbeiana) larvae during metamorphosis. | the ontogeny of gonadotrophs and thyrotrophs in the bullfrog pituitary was examined immunohistochemically using monoclonal antibodies against bullfrog lutropin beta-subunit (lh beta), follitropin beta-subunit (fsh beta) and its alpha-subunit, and polyclonal anti-human thyrotropin beta-subunit (tsh beta) serum. immunoreactive alpha-subunit- and tsh beta-, but not fsh beta- and lh beta-containing cells were observed at embryonic stage 24 (shumway's classification). immunoreactive fsh beta cells fi ... | 1991 | 1783276 |
| ouabain-insensitive na-atpase activity in homogenates from different animal tissues. | 1. two na(+)-stimulated atpase activities were determined in gill homogenates from squid, shrimp and teleost fish; in kidney slice homogenates from teleost fish, bullfrog, toad, iguana, chicken, duck, rat, pig and cow, as well as in homogenates from rat small intestinal cells, brain cortex and liver slices. the two na(+)-stimulated atpase activities, the na- and the na,k-atpase, showed a different behavior toward k+ and ouabain. 2. the ouabain-insensitive, k(+)-independent, na-atpase activity fo ... | 1991 | 1831096 |
| the complete amino acid sequence of growth hormone of the bullfrog (rana catesbeiana). | the primary structure of growth hormone (gh) isolated from the adenohypophysis of the bullfrogs (rana catesbeiana) was determined. the hormone was reduced, carboxymethylated and subsequently cleaved with cyanogen bromide. intact bullfrog gh was also digested with lysyl endopeptidase and trypsin. the resulting fragments were separated by reverse-phase high-performance liquid chromatography and subjected to sequence analysis using an automated gas-liquid sequencer employing the edman method. bullf ... | 1991 | 1859828 |
| comparison of lipolytic and antilipolytic activities of lower vertebrate growth hormones on chicken adipose tissue in vitro. | mammalian and avian growth hormones (gh) (pituitary derived or biosynthetic) exert two effects on chicken adipose tissue explants in vitro. they (i) increase the basal rate of glycerol release a lipolytic effect) and (ii) inhibit glucagon-stimulated glycerol release (an antilipolytic effect). the ability of lower vertebrate gh preparations to exert lipolytic and antilipolytic effects was examined and biological activity was compared to differences in amino-acid residue sequences and to predicted ... | 1991 | 1871152 |