| autoregulatory system of insulin degradation in liver. ii. relationship between blood insulin levels and gsh-dependent insulin degrading activity in liver and blood. | an autoregulatory system of insulin degradation in the liver in which the rate of insulin metabolism changes in response to fluctuation in its blood levels, was investigated. in the plasma of rats and man in the absence of reduced glutathione (gsh), insulin degradation was not observed, but when a sufficient amount of reduced glutathione was added, the plasma did degrade insulin. this gsh-dependent insulin degrading activity in plasma was quite similar to that in liver in its nature. in rats, th ... | 1976 | 4693 |
| comparison of the effects of neuroleptic drugs on pre- and postsynaptic dopaminergic mechanisms in the rat striatum. | | 1976 | 4724 |
| reduction of tertiary amine n-oxides by liver microsomal cytochrome p-450. | | 1976 | 4725 |
| simple model for hormone-activated adenylate cyclase systems. | a simple model is developed to explain the activation of rat liver plasma membrane adenylate cyclase atp pyrophosphate-lyase (cyclizing), ec 4.6.1.1 by guanosine nucleotides and glucagon and the dependence of the catalytic rate on mg2+, h+, and substrate concentrations. the basic model proposes that the adenylate cyclase system can exist in two states, a and b; that activating ligands bind preferentially to the b state; and that only the b state is active. kinetic data are quantitatively fit to ... | 1976 | 4796 |
| beta-adrenergic receptors in rat liver: effects of adrenalectomy. | the response of rat liver adenylate cyclase atp pyrophosphate-lyase (cyclizing), ec 4.6.1.1 to catecholamines is enhanced after adrenalectomy. to investigate this phenomenon, we developed an in vitro assay for beta-adrenergic receptors of plasma membranes derived from livers of control and adrenalectomized rats, using 125iiodohydroxybenzylpindolol (ihyp), a potent beta-adrenergic receptor antagonist. binding of ihyp reached equilibrium within 30 min and dissociation occurred with a half-time of ... | 1976 | 4798 |
| alpha-msh and mif-2 effects on serotonin levels and accumulation in various rat brain areas. | levels as well as accumulation of serotonin (5-ht) were measured in various brain regions of the rat after administration of alpha-melanocyte-stimulating hormone (msh) and pro-leu-gly-nh2 (mif-i). the method used in determining the serotonin measured both 5-oh-tryptamine (5-ht) and 5-methoxytryptamine (5-mt). no statistically significant changes in levels or accumulation of serotonin after pargyline injection were found when unoperated control rats were treated with either msh or mif-i. similar ... | 1975 | 4814 |
| enzyme activity in sleep and sleep deprivation. | liver tyrosine transaminase activity is low during the day when the rats are mostly asleep and high during the night when they are awake. when wakefulness was imposed for 8 hr during daylight on the day of the experiment and the rats were allowed to sleep for the following 3 hr during darkness, the tyrosine transaminase activity became high during the day and low at night. that this reversal in enzyme activity is not mediated by the pituitary-adrenal axis is demonstrated by the fact that in adre ... | 1975 | 4817 |
| rate-dependent effects of drugs: a review of the literature. | it has been claimed that the effects of amphetamines on schedule-controlled behavior depend to a large extent on the rate of responding in control conditions. a review of the literature shows that there is considerable support for this hypothesis if the behavior is not suppressed by aversive procedures, is not under the control of powerful external stimuli or is not occurring very infrequently. the extension of a rate-dependency hypothesis to the effects of other drugs has less empirical support ... | 1976 | 4819 |
| schedule-induced oral self administration of etonitazene. | rats were induced to drink either a saline-etonitazene solution or a saline solution with a schedule-induced polydipsia paradigm. when water was freely available, the rats continued to drink the saline solution or the saline-etonitazene solution, rather than the water. when the locations of the solutions were switched, the rats that were drinking saline switched to water (drank at the usual location), but the rats that were drinking saline-etonitazene continued to drink the saline-etonitazene so ... | 1976 | 4820 |
| schedule-induced narcotic ingestion. | | 1975 | 4822 |
| the mechanism of the utero-inhibitory effect of beta-sympathomimetics. | | 1975 | 4826 |
| the biological actions of thyrotropin. | | 1975 | 4827 |
| macrocyclic intermediates in the biosynthesis of porphyrins. | the hepta-, hexa- and penta-carboxylic porphyrins found in the faeces of rats poisoned with hexachlorobenzene have been separated by high-pressure liquid chromatography and characterized largely by spectroscopie methods. their structures were confirmed by total synthesis, as part of a programme in which eleven of the fourteen hepta-, hexa- and penta-carboxylic porphyrins derived from uroporphyrin iii have now been synthesized as their methyl esters. the four isomeric heptacarboxylic and three of ... | 1976 | 4837 |
| study of cystinaminopeptidase heterogeneity in animal sera by the isoelectric focusing method. | study of the quantitative distribution of cystinaminopeptidase activity in the serum of pregnant and control animals (cow, sheep and rat) by the isoelectric focusing method showed heterogeneity of the cystinaminopeptidase activity of the animals' serum enzymatic system, which was well pronounced in the cow and rat and less pronounced in the sheep. the authors assume from their results that the principal difference between the pregnant and control animals is not the total increase in the level of ... | 1976 | 4848 |
| inhibition of prostaglandin biosynthesis by sulphasalazine and its metabolites. | sulphasalazine (sz) inhibits prostaglandin (pg) biosynthesis in vitro with a potency comparable to that of aceylsalicylate. the metabolites of sz, sulphapyridine and 5-aminosalicylic acid, were of considerably lower potency as inhibitors of pg biosynthesis in the synthetase preparations used. th inhibition of prostaglandin production by sz could at least partly account for the clinical utility of sulphasalazine in ulcerative colitis. sulphapyridine may help to maintain inhibitory concentrations ... | 1976 | 4854 |
| the effect of various chlorpromazine derivatives on the apomorphine-elicited inhibition of synaptosomal tyrosine hydroxylase activity. | the effects of chlorpromazine and of some metabolites of chlorpromazine on the apomorphine-elicited inhibition of synaptosomal tyrosine hydroxylase activity were investigated. chlorpromazine, nor1-chlorpromazine and 7-hydroxychlorpromazine reverse the apomorphine-elicited inhibition of tyrosine hydroxylase activity while nor1-chlorpromazine sulfoxide and nor2-chlorpromazine sulfoxide have no effect on this inhibition. 6-hydroxychlorpromazine and promethazine also reverse the enzyme inhibition by ... | 1975 | 4859 |
| effects of benzodiazepines on the binding of tryptophan in serum. consequences on 5-hydroxyindoles concentrations in the rat brain. | benzodiazepines (diazepam, oxazepam, chlordiazepoxide) inhibited competitively the binding of tryptophan onto rat serum albumin. as a result, in vivo treatment with one of these compounds (chlordiazepoxide for instance) induced a significant increase in the concentration of free tryptophan in serum. these observations suggest that the high levels of both 5-hydroxyindoles and tryptophan which occurred in the rat brain after any benzodiazepine administration could be at least partly the consequenc ... | 1975 | 4860 |
| functional heterogeneity within neurotransmitter systems. | this paper reviews experiments that have revealed distinct differences between the dorsal and median raphe nuclei in the rat midbrain. the raphe nuclei appear to be hetrogeneous with respect to their anatomical projections to the forebrain, their relevance to specific behaviors, and their pharmacological responses. startle response measures are useful indicators of the functional state of serotonergic system originating in the median raphe. as a way to study individual cells within the various r ... | 1975 | 4862 |
| in vitro and in vivo studies of (1-sarcosine, 8-threonine) angiotensin ii. | the capacity of (1-sarcosine, 8-threonine) angiotensin ii to block the contractile and pressor effects of exogenous and endogenous angiotensin ii was examined. in isolated rabbit aorta, the pa2 value (from pa2 plots) for the analog was 8.75 +/- 0.11. both the maximum response and the slope of the dose-response curve to angiotensin ii were unchanged by the analog. in ganglion-blocked vagotomized rats, infusion of the analog produced a dose-dependent blockage of the angiotensin ii pressor effect. ... | 1976 | 4864 |
| the role of aflatoxin metabolism in its toxic lesion. | | 1976 | 4903 |
| irreversible protein binding of norethisterone (norethindrone) epoxide. | 14,15-3h-norethisterone-4 beta, 5 beta-epoxide, a metabolite of norethisterone, was incubated with several proteins and nucleic acids. after 30 min incubation 0.19 nmol of the epoxide were irreversibly bound per mg albumin which contains free sulfhydryl groups; proteins without sh-groups, such as concanavalin a, gamma-globulin, dna and rna, did not irreversibly bind norethisterone epoxide. a superoxide (o2) generating enzyme system comprised of xanthine oxidase and hypoxanthine was capable of ca ... | 1976 | 4905 |
| content of catecholamines in the hypothalamus and different parts of the stomach in experimental ulcer and change in their level under the effect of gangleron. | | 1975 | 4936 |
| effect of quateron on the state of contractile processes in the myocardium in experimental acute cardiac insufficiency. | | 1975 | 4937 |
| purification of a catecholamine-rich fraction with prolactin release-inhibiting factor (pif) activity from porcine hypothalami. | | 1976 | 4944 |
| pharmacological action of triazolam. | | 1975 | 4945 |
| the effect of halothane anaesthesia upon cerebral oxygen consumption in the rat. | the influence of halothane (0.6 and 2%) upon cerebral (cortical) blood flow (cbf) and cerebral metabolic rate for oxygen (cmro2) was studied in artificially ventilated rats, using a modified technique of kety & schmidt (1948). the values obtained in halothane anaesthesia were compared to those recorded in nitrous oxide anaesthesia, or to those measured in unanesthetized animals given an analgesic drug (fentanyl citrate). although it could be confirmed that halothane induces vasodilatation in the ... | 1976 | 4948 |
| effect of beta-adrenoreceptor blockade on rat cardiac and skeletal muscle ph. | the effect of catecholamines on the intracellular ph of rat cardiac and skeletal muscle during varying extracellular acid-base states was determined. intracellualr ph (phi) was calculated from the distribution of 14cdmo. acid-base disturbances were produced by placing the animals in an environmental chamber containing 10 or 20% co2 or by administering hcl or nahco3. two hours later the animals were anesthetized with sodium pentobarbital and blood and tissue samples obtained. in one series of ani ... | 1976 | 4982 |
| evidence for dimethyltryptamine (dmt) as a naturally-occurring transmitter in mammalian brain. | | 1976 | 4987 |
| a simplified assay of 4-methyl sterol oxidase of liver microsomes. | | 1976 | 4991 |
| a modification of determination for glucosamine and galactosamine in glycoprotein with the amino acid analyzer. application to total acid hydrolyzate of rat renal glomerular basement membrane. | | 1976 | 4992 |
| toxicological characteristics of ampicillin. | toxocity of ampicillin trihydrate was studied in acute and chronic experiments. it was shown that the antibiotic had low acute toxicity, did not cumulate and had no skin-irritating effect. on its inhalation in concentrations of 5 mg/m3 for 4 months, ampicillin induced allergization of albino rats, decreased their immunity. the general toxic effect of the drug was slightly pronounced. ampicillin in a concentration of 0.1 mg/m3 induced tension of the immunological reactivity of the organism. the m ... | 1975 | 5051 |
| benorylate interaction with indomethacin and phenylbutazone. | the simlutaneous oral administration of benorylate (4-(acetamido) phenyl 2-acetoxybenzoate) with either indomethacin or phenylbutazone to rats suffering from freund's adjuvant-induced arthritis leads to an anti-inflammatory effect which is significantly greater than the effect of the same drugs administered alone. such an additive anti-inflammatory effect is not apparent when the metabolites of benorylate (paracetamol, acetylsalicylic acid) are administered with indomethacin or phenylbutazone. p ... | 1976 | 5064 |
| metabolism and ultrastructure in ovaries of alloxan-diabetic juvenile rats. | tests were carried out on the influence of alloxan-induced diabetes mellitus on the metabolism and the ultrastructure of ovaries of juvenile rats. the diabetes mellitus caused the following changes in the metabolism: reduction in the concentration of atp and nadph, increase in the lactate/pyruvate quotient to above 40, reduction in the atp/adp quotient to below 1, reduction in the level of activity of the hydrogen-conveying enzymes g-6-p-dehydrogenase, isocitrate dehydrogenase and malate dehydro ... | 1976 | 5067 |
| studies on l-arginase of the small intestine. i. topographical distribution and some properties of the small intestine l-arginase in the rat. | | 1975 | 5075 |
| decrease of glutathione and induction of gamma-glutamyltransferase by dibutyryl-3', 5'-cyclic amp in rat liver. | | 1976 | 5080 |
| determination and characterization of neuron specific protein (nsp) associated enolase activity. | | 1976 | 5081 |
| effect of various 6-hydroxydopamine treatments during development on growth and ingestive behavior. | destruction of catecholamine-containing fibers in brain at 5 days of age with intracisternal injection of 6-hydroxydopamine reduced body growth, intake of a sucrose solution, and acquisition of an active avoidance response. further characterization of behavioral deficits indicated that treated animals also showed reduced ingestion of saline solution when injected with desoxycorticosterone and a decreased eating response to insulin. in addition, all of these deficits produced by catecholamine dep ... | 1975 | 4816 |
| alpha-msh and mif-i effects on catecholamine levels and synthesis in various rat brain areas. | attempts were made to find a biochemical correlate with previously observed behavioral alterations after administration of alpha-melanocyte-stimulating hormone (msh) and msh release-inhibiting factor (mif-i). brains of intact and hypophysectomized (hypox) rats were analyzed for endogenous catecholamine levels and the disappearance rate of endogenous norepinephrine (ne) after treatment with the tyrosine hydroxylase inhibitor alpha-methyl-para-tyrosine (ampt). the studies undertaken show the follo ... | 1975 | 4815 |
| specific positions involved in enzyme catalyzed covalent binding of benzoapyrene to poly(g). | covalent binding of benzoapyrene to poly(g) was studied with the use of a radioactive assay and specifically labeled substrates to define the role of the 1, 3- and 6-positions of the hydrocarbon during this process. binding was shown to be dependent on microsomes, nadph, o2 and poly(g). 7, 8-benzoflavone and 2', 2'-diethylaminoethyl-2, 2-diphenyl valerate were inhibitory w.hereas modulators of epoxide hydrase activity had little effect. 3h and 14c studies suggested a possible loss of one to two ... | 1976 | 4795 |
| activation and nuclear translocation of protein kinase during transsynaptic induction of tyrosine 3-monooxygenase. | the tyrosine-3-monooxygenase activity l-tyrosine, tetrahydropteridine: oxygen oxidoreductase (3-hydroxylating); ec 1.14.16.2 of rat adrenal medulla is induced 20-24 hr after the injection of reserpine (16 mumol/kg intraperitoneally). this and other inducing stimuli increase the 3': 5'-cyclic amp (camp) content in the medulla for longer than 60 min and activate the camp-dependent protein kinase (atp: protein phosphotransferase; ec 2.7.1.37) for several hours. corticotropin (acth), dopamine, and p ... | 1976 | 4793 |
| phosphate transport by isolated renal brush border vesicles. | a sodium dependent specific transport system for phosphate is present in the brush border microvilli but absent from the basal-lateral plasma membranes. the apparent affinity of this transport system for phosphate is 0.08 mm at 100 mm sodium and ph 7.4. it is inhibited competitively by arsenate with an apparent inhibitor constant of 1.1 mm (100 mm sodium, ph 7.4). sodium dependent phosphate uptake is two times higher at ph 8 compared to the uptake observed at ph 6. the apparent affinity of the t ... | 1976 | 4766 |
| local renal graft-versus-host reaction: sequential ultrastructural study. | a sequential study has been made of the ultrastructure of local renal graft-versus-host reactions produced in cyclophosphamide-pretreated rats by injection of either allogeneic or xenogeneic (mouse) spleen cells beneath the renal capsule. early in the reaction, immunoblasts were seen between the outer cortical tubules, and there was associated interstitial oedema and tubular degeneration. in places, several small lymphocytes were observed clustered around and in close cytoplasmic contact with in ... | 1975 | 4760 |
| induction of tyrosine hydroxylase in the superior cervical ganglia of rats: opposite influence of muscarinic and nicotinic receptor agonists. | | 1976 | 4743 |
| interaction of walker 256 mammary carcinoma and foetal rat liver in organ culture inhibits enzyme maturation. | | 1976 | 4736 |
| steady-state enzyme kinetics of the pancreatic ribonucleases from five mannalian species. | the kinetic parameters km, k+2 and k+2/km of the pancreatic ribonucleases (ec 3.1.4.22) from cow, giraffe, horse, rat and lesser rorqual have been determined, using 2',3'-cyclic cytidine monophosphate and 2',3'-cuclic uridine monophosphate as substrates. no large differences were found between the activities of the five enzymes. the relative differences between the activities of the five enzymes are mainly due to differences in the rates of hydrolysis and not to differences in the affinities for ... | 1976 | 5144 |
| aspartate and glutamate as possible transmitters of excitatory hippocampal afferents. | | 1976 | 4735 |
| inhibition by sulfobromophthalein of mitochondrial translocation of anions and adenine nucleotides: effects upon liver adenosine triphosphate and possible correlation with inhibition of bile flow in the rat. | unconjugated sulfobromophthalein (bsp) inhibits state iii respiration of rat liver mitochondria. it competitively inhibits the translocation into mitochondria of citrate, malate, phosphate and adenosine diphosphate, as studied by the inhibitor stop method. a double-beam spectrophotometric study strongly suggests that glutamate translocation is similarly inhibited. after perfusion of 65 mumol/hr/100 g for 90 minutes, bile flow is inhibited by 82% and liver adenosine triphosphate (atp) falls by 60 ... | 1976 | 4612 |
| effect of para-aminohippurate on renal glutamine metabolism in the rat. | after para-aminohippurate (pah) infusion into rats, urine ph decreased and urine ammonium excretion increased. because augmented urine flow and decreased urine ph could not explain entirely the enhanced ammonium excretion, an increased ammonia production was postulated as a contributing influence. this was supported by the in vitro findings that pah could increase slice ammoniagenesis from glutamine. the ability of pah to stimulate ammoniagenesis in vitro was attributed to enhanced phosphate-dep ... | 1976 | 4611 |
| a new technique for studying the exocrine pancreatic secretion in rat (author's transl). | | 1975 | 5160 |
| effects of axotomy on the trans-synaptic regulation of enzyme activity in adult rat superior cervical ganglia. | the effects of surgical transection of the postganglionic nerve trunk of the superior cervical ganglion on the total protein content and levels of the enzymes tyrosine hydroxylase, dopa decarboxylase and choline acetyltransferase have been studied in the adult rat. there is a minor decrease in the total activities of these 3 enzymes accompanied by a large increase in the total protein content of the ganglion. the trans-synaptic induction of the enzyme tyrosine hydroxylase by reserpine is not aff ... | 1976 | 5175 |
| effects of egg factors on cyclic nucleotide metabolism in sea urchin sperm. | cyclic amp in strongylocentrotus purpuratus sperm was elevated approximately 2-fold by theophylline or 1-methyl-3-isobutylxanthine. factors released from sea urchin eggs (fre) elevated sperm cyclic amp by about 7-fold within 1 min, and the combination of fre with theophylline increased sperm cyclic amp up to 100-fold within 1 min. cyclic gmp in sea urchin sperm was slightly elevated by theophylline, but was lowered by fre. cyclic gmp in sperm treated with fre plus theophylline was not higher tha ... | 1976 | 4475 |
| guanylate cyclase and cyclic guanosine 3':5'-monophosphate phosphodiesterase activities and cyclic guanosine 3':5'-monophosphate levels in normal and transformed fibroblasts in culture. | to investigate the role of guanosine 3':5'-monophosphate (cyclic gmp) in cultured cells we have measured guanylate cyclase and cyclic gmp phosphodiesterase activities and cyclic gmp levels in normal and transformed fibroblastic cells. guanylate cyclase activity is found almost exclusively in the particulate fraction of normal rat kidney (nrk) and balb 3t3 cells. enzyme activity is stimulated 3- to 10-fold by treatment with the detergent lubrol px. however, enhancement of guanylate cyclase by fib ... | 1976 | 4444 |
| properties of soluble and particulate cysteine sulfinate decarboxylase of the adult and the developing rat brain. | some properties of cysteine sulfinate decarboxylase (csd) activity were studied in the pellet and supernatant of a 18,000 x g centrifugation of isotonic sucrose rat brain homogenates. about 50% of the enzyme activity was found associated to the particulate fraction and 16% of the activity remained particle bound after hypo-osmotic shock of the 18,000 x g pellet. the activity of the 18,000 x g supernatant showed a lower dependence on exogenous pyridoxal phosphate (plp) than the activity in the pa ... | 1976 | 5179 |
| intracellular distinction between peroxidase and catalase in exocrine cells of rat lacrimal gland: a biochemical and cytochemical study. | the lacrimal gland (glandula orbitalis externa) of rat contains both peroxidase and catalase and was used as a model for biochemical and cytochemical distinction between peroxidase and catalase. both enzymes were isolated by ammonium sulfate precipitation from tissue homogenates, and the effects of fixation with glutaraldehyde and various conditions of incubation were investigated colorimetrically using dab as hydrogen donor. the lacrimal gland peroxidase is strongly inhibited by glutaraldehyde ... | 1976 | 4418 |
| effects of pregnancy on the development of acute uremic syndrome in the rat. | we evaluated the contributory role which gestational metabolic adaptions may play in the development of acute uremic syndrome in rats by studying the effects of nephrectomy in pregnant and nonpregnant animals. whereas no significant differences in creatinine and uric acid concentrations were found between control and pregnant rats, urea concentrations were significantly lower in the pregnant animals before, as well as well as 6, 12 and 24 h after, bilateral nephrectomy. it is suggested that crea ... | 1976 | 4412 |
| disadvantages of acid precipitation of proteins during the assay of blood glucose by the enzymatic glucose oxidase-peroxidase system. | in the enzymatic procedure for blood sugar by means of glucose oxidase, acid protein precipitation of blood by perchloric acid or trichloracetic acid liberated oxidizing substances, which enhanced the coloration density in oxidizing the reduced chromogen of the reaction mixture, independently of the hydrogen peroxide generated from glucose, and would give false high values of glycemia, if additional precautions had not been taken. these substances, increasing considerably with times and temperat ... | 1976 | 5200 |
| evidence for a renal alpha-adrenergic receptor inhibiting renin release. | the mechanism by which clonidine suppresses renin release was investigated in conscious rats. this suppression was studied by means of selected autonomic interventions in conjunction with changes in sodium balance. serum renin activity and direct arterial pressure were monitored. clonidine administration suppressed basal (by 68-85%), diuretic-induced (by 89%), and sympathetic nervous system-mediated (by 75-100%) renin release. cholinergic, ganglionic, and peripheral sympathetic neuronal blockade ... | 1976 | 5201 |
| cellular basis for increased sensitivity of vascular smooth muscle in spontaneously hypertensive rats. | there is evidence that hypersensitivity of vascular muscle to neurotransmitters contributes to the development of hypertension. comparison of the caudal arteries of spontaneously hypertensive rats (shr) and their genetically related kyoto-wistar normotensive control rats (knr) showed that although there is no difference in membrane potential under unstimulated conditions, greater depolarization of the shr vascular muscle cells by norepinephrine occurs at concentrations which cause greater contra ... | 1976 | 5207 |
| suppression of experimental allergic encephalomyelitis in guinea-pigs with poly-l-lysine. | poly-l-lysin (pll) given subcutaneously in a dose of 3 mg/day suppresses experimental allergic encephalomyelitis in guinea-pigs. the suppressive effect of pll can still be demonstrated when administration is begun 8 days post-immunization. the effect is disease- and species-specific since pll (3 mg/day) does not suppress experimental allergic orchitis in guinea-pigs, nor does it suppress eae in rats (1-5 mg/day). pll (0-2 mg/day) does not decrease the severity of graft-versus-host disease (gvh) ... | 1975 | 5213 |
| some properties and occurrence of glutamine synthetase in fish. | | 1976 | 5230 |
| mixed function oxidases and nitroreductases in hepatopancreas of homarus americanus. | | 1976 | 5238 |
| effect of nafenopin (su-13437) on liver function. influence on the hepatic transport of phenolphthalein glucuronide and chlorothiazide. | in rats treated with the hypolipidemic drug, nafenopin (np), for 2 days the biliary excretion of phenolphthalein glucuronide (ppg) was markedly decreased, while in contrast that of chlorothiazide (ctz) was enhanced. this suggests the existence of independent hepatic transport mechanisms for these two anions. for both ppg and ctz blood disappearance curves showed an initial, rapid phase followed by a second, slow phase. the rapid phase for both compounds is affected only slightly by pretreatment ... | 1976 | 5253 |
| binding of radioactivity from (14c)thiourea to rat lung protein. | binding of radioactivity from 14cthiourea (tu) to rat lung protein was found to occur in vitro. two binding sites are present. one possesses low affinity/high capacity while the other is characterized by high affinity/low capacity. in vitro binding of 14ctu to lung protein can be antagonized by the presence of either unlabeled congeners (alpha-napthylthiourea or phenylthiourea) or thiol-containing compounds (cysteine, reduced glutathione). conversely, depletion of lung-reduced glutathione by mea ... | 1976 | 5255 |
| properties of rat lens phosphofructokinase. | two interconvertible forms of phosphofructokinase (pfk) have been eluted from a deae-cellulose column from the supernatant fraction of rat lens homogenates centrifuged at 96,000 x g for 1 hour at 0 to 4 degrees c. the interconversion can be manipulated by a change in the ph of the extracting and eluting buffers. pfk-i is the dominant form at ph between 7.4 to 7.05, while pfk-ii dominates at ph 7.4 to 8.2. pfk-ii is believed to be the functional form; it is inhibited by high concentrations of atp ... | 1976 | 4411 |
| effect of long-term starvation on the rat liver lysosomes. | the effect of 120- and 240-h starvation on rats hepatocytes ultrastructure and particularly the changes of the lysosomes were studied. eelectronmicroscopically and cytochemically there have been observed diminution of the number of mitochondria and degranulation and vacuolzation of the er. at the same time golgi complex was hypertrophied and the number of lysosomes was much increased, mainly those of the autophagic type. biochemically was shown, that the activity of some acid hydrolases (beta-gl ... | 1976 | 4404 |
| metabolism of trans-stilbene in rabbits and rats. | the biotransformation of intramuscularly administered 14c-labeled trans-stilbene was investigated in both rabbits and rats. in rabbits radioactivity was excreted (78.8% in 17 days) almost exclusively in the urine. in rats, feces accounted for more than half of the total excretion (80.3% in 19 days). hydroxylated metabolites in urine and feces were identified by thin-layer chromatography and quantitated by liquid scintillation counting. they were 4-hydroxy and 4,4'-dihydroxystilbene, and the two ... | 1976 | 5260 |
| motility of the rat oviductal tract isolated in different stages of the sex cycle. effects of catecholamines. | physiological and pharmacological characteristics of the spontaneous motility of rat oviductal tracts (the coiled oviduct plus its mesosalpinx), isolated in proestrus, estrus or metestrus, are described. the initial contractile tension (recorded following isolation) was comparable in the three stages of the cycle, but its decrement with time was greater in metestrus than in proestrus; the opposite being observed regarding the rate of contractions. norepinephrine and phenylephrine depress motilit ... | 1975 | 4398 |
| the interrelationships between the in situ fluxes of water, electrolytes and glucose by hymenolepis diminuta. | | 1976 | 4401 |
| proline in fascioliasis: iii. activities of pyrroline-5-carboxylic acid reductase and pyrroline-5-carboxylic acid dehydrogenase in fasciola. | | 1976 | 4402 |
| studies on urinary arylsulphatase activity in vitamin a deficient rats. | urinary arylsulphatases (e.c.3.1.6.1) a and b were increased in male rats fasted for 24 hours. excretion of non dialysable protein nitrogen decreased whereas creatinine excretion increased. on refeeding diet arylsulphatase a activity was restored to normal whereas arylsulphatase b was not normalised. a single oral supplementation of vitamin a acetate (20 000 iu) to rats fasted for 24 hours resulted in a significant reduction of both arylsulphatase a and b eventhough no further reduction of prote ... | 1976 | 4403 |
| partial purification and characterization of a reduced nicotinamide adenine dinucleotide phosphate-linked aldehyde reductase from heart. | | 1976 | 5092 |
| the effect of sympatholytic and sympathomimetic agents on acetylcholinesterase and cholinesterase activity, in vitro. | | 1976 | 5093 |
| effect of morphine on the potassium-induced change in the level of reduced pyridine nucleotides and cytochromes in brain slices. | | 1976 | 5094 |
| tyrosine hydroxylase in snail (helix pomatia) nervous tissue. | | 1976 | 5096 |
| activation of the o-glucuronide of the carcinogen n-hydroxy-n-2-fluorenylacetamide by enzymatic deacetylation in vitro: formation of fluorenylamine-trna adducts. | | 1976 | 5097 |
| the role of neural input in the effects of morphine on the rat adrenal medulla. | | 1976 | 5098 |
| anti-leukaemia activity as a bystander effect of graft-versus-host reactions. | the production of graft-versus-host (gvh) reactions in (pvgc x wistar) f1 hybrids by the transfer of pvgc spleen cells resulted in significant resistance of these recipients to a subsequent challenge with the pvgc leukaemia. protection was markedly dependent on dose and timing of allogeneic cell transfer and was abrogated by irradiation of the cells prior to transfer. gvh activity was shown to be a prerequisite for induction of the protective effect but was equally effective when produced by the ... | 1976 | 5100 |
| the effect of aflatoxins on the incorporation of rna and protein precursors by isolated hepatocytes. | hepatocytes prepared by a simplified enzymatic technique were active in the incorporation of rna and protein precursors into acid-insoluble material. the incorporation of rna precursors was very markedly inhibited by low levels of aflatoxin b1 and g1 but not by aflatoxins b2 and g2. the activity of mixed function oxidases (mfo), the drug-metabolizing system of the endoplasmic reticulum, could be suppressed in these cells by skf525a or stimulated by nadph. skf525a caused a reduction in the inhibi ... | 1976 | 5101 |
| synthesis and properties of carbonylbis(methionyl)insulin, a proinsulin analogue which is convertible to insulin by cyanogen bromide cleavage. | the preparation and use of carbonylbis (l-methionine p-nitrophenyl ester) as a reversible cross-linking reagent for insulin are described. the reaction of 1 equiv of reagent with zinc insulin in dimethylformamide in the presence of triethylamine yields as one of the products nalphaa1, nepsilonb29-carbonylbis(methionyl)insulin, (cbm-insulin). the cbm-insulin was characterized by end group analysis and by the products formed on tryptic and chymotryptic cleavage. it possessed 91% of the immunologic ... | 1976 | 5108 |
| histidine ammonia-lyase from rat liver. purification, properties, and inhibition by substrate analogues. | histidine ammonia-lyase (ec 4.3.1.3) from rat liver was purified more than 250-fold to near homogeneity. electrophoretic determinations indicated a native molecular weight of approximately 200,000. the enzyme has a ph optimum of approximately ph 8.5. the minimum km for l-histidine was 0.5 mm at ph 9.0. the michaelis constant in the physiological ph range was, however, more than 2.0 mm. d-alpha-hydrazinoimidazolylpropionic acid was found to be a potent competitive inhibitor of liver histidine amm ... | 1976 | 5116 |
| isolation of brain endopeptidases: influence of size and sequence of substrates structurally related to bradykinin. | two thiol-activated endopeptidases with ph optima near ph 7.5 were isolated from the supernatant fraction of rabbit brain homogenates by deae-cellulose chromatography, gel filtration and isoelectrofocusing. peptide bond hydrolysis was measured quantitatively by ion-exchange chromatography with an amino acid analyzer. brain kininase a hydrolyzes the phe5-ser6 peptide bond in bradykinin (bk), arg1-pro2-pro3-gly4-phe5-ser6-pro7-phe8-arg9. it is isoelectric near ph 5.2 and has a molecular weight of ... | 1976 | 5120 |
| hydrolysis of neutral glycerides by lipases of rat brain microsomes. | the hydrolysis of monoacylglycerol and diacylglycerol by rat brain microsomes was followed by measuring the release of glycerol and monooleylglycerol from dispersions of water insoluble glyceryl esters of oleic acid. the microsomes showed three lipolytic activities. one activity, optimal at ph 4.8, catalyzed the hydrolysis of diacylglycerol but not monoacylglycerol. two other lipolytic activities, optimal at ph 8.0-8.6, catalyzed the hydrolysis of both diacylglycerol and monoacylglycerol. the ph ... | 1976 | 5151 |
| the effect of soluble rat liver proteins on the activity of microsomal stearoyl-coa and linoleoyl-coa desaturase. | 1. the influence of bovine serum albumin and soluble rat liver proteins on the activity of rat liver microsomal delta9 and delta6 desaturases has been studied. 2. in the absence of bovine serum albumin, the delta9 desaturase which converts stearoyl-coa into oleoyl-coa, shows a non-linear correlation between enzyme activity and protein concentration. 3. optimum concentrations of bovine serum albumin have three main effects on the enzyme activity: (i) establishes a linear relationship between enzy ... | 1976 | 5153 |
| effect of ph on the separation of rat liver cells. | the effect of calcium ions, temperature and ph on the number of cells separated in the course of dispersion procedure was studied. the maximum number of separated cells corresponds to ph 6.8. mechanical resistibility of the cells in suspension was found to grow linearly within ph interval 5.2-8.8. | 1976 | 5155 |
| biogenic amines and related enzymes in the circumventricular organs of the rat. | | 1976 | 5177 |
| a quantitative comparison of the formation of synapses in the rat superior cervical sympathetic ganglion by its own and by foreign nerve fibres. | the rat superior cervical sympathetic ganglion (scg) has about 36,000 neurones in a volume of about 1 cu.mm. there are about 8.8 x 10(6) synapses, and 6000-9000 preganglionic axons. section of the preganglionic chain causes a loss of 93% of the synapses. in the denervated scg there are 0.6 x 10(6) remaining ('intrinsic') synapses, and a proportion of the synaptic sites are identifiable as vacated synaptic thickenings (3 x 10(6) per scg, as compared with 0.5 x 10(6) in the normal intact scg). aft ... | 1976 | 5178 |
| some properties of acetylcholinesterase from rat retina. | acetylcholinesterase (ache, ec 3.1.1.7) of rat retina was studied with respect to its kinetic and other properties, and a comparison was made with the enzyme from brain. the subcellular distribution of the retinal ache showed that the enzyme was concentrated in the synaptosomal-mitochondrial fraction although in the brain the ache was distributed more evenly between the fractions studied. the enzyme from both retina and brain was easily solubilised and exhibited a km of the order of 10(-4) m. th ... | 1976 | 5185 |
| the metabolic activation of the carcinogen 1'-hydroxysafrole in vivo and in vitro and the electrophilic reactivities of possible ultimate carcinogens. | administration of 2',3'-3h-1'-hydroxysafrole to rats or mice resulted in the formation of hepatic dna-, ribosomal rna-, and protein-bound 3h derivatives. alkaline digestion of the 3h-protein released 0.1 to 0.3% of the 3h as a derivative that was identified as 3'-methylmercaptoisosafrole by its cochromatography in five solvent systems with the synthetic compound. 1'-hydroxysafrole was metabolized at a low rate by rat and mouse liver cytosols in a 3'-phosphoadenosine 5'-phosphosulfate-dependent r ... | 1976 | 5188 |
| uptake and disposition of chlorinated biphenyls by isolated perfused rat liver. | the hepatic disposition of four chlorinated biphenyls was studied in isolated perfused rat liver preparations perfused with 30% rat blood. biliary excretion of 14c-labeled 4-chlorobiphenyl (1-cb): 4,4'-dichlorobiphenyl (2-cb): 2,4,5,2',5'-pentachlorobiphenyl (5-cb) and 2,4,5,2',5'-hexachlorobiphenyl (6-cb) appeared to be inversely related to increased chlorination. each of the compounds was rapidly taken up by the liver from the circulating perfusate. after 4 hr of perfusion, biliary excretion o ... | 1976 | 5256 |
| (14c)methylphenidate hydrochloride. studies on disposition in rat brain. | studies with 14cmethylphenidate-hcl were carried out in rats administered the drug intravenously or intraperitoneally. levels of total radioactivity and parent drug were measured in plasma, brain, and certain brain regions up to 6 hr after dosing. the intravenous route of administration was characterized by rapid entry into brain; during the first half hour, brain levels were 3- to 6-fold higher than those obtained by the intraperitoneal route. at later time periods, brain and plasma concentrati ... | 1976 | 5258 |
| qualitative metabolic fate of phenoxybenzamine in rat, dog, and man. use of 15n-labeling. | administration of an equimolar mixture of unlabeled and 15n-labeled phenoxybenzamine to rats and dogs facilitated identification of urinary metabolites by gas chromatography/chemical-ionization mass spectrometry by virtue of the the conspicuous equal-intensity ion pairs produced. by use of this technique n-benzyl-n-phenoxyisopropylamine (iii), n-benzyl-n-(p-hydroxy-phenoxyisopropyl)amine (iv), and 2-benzylamino-1-propanol (vi) were identified as metabolites in rats. phenoxyisopropylamine (v) as ... | 1976 | 5261 |
| identification of the urinary metabolites of 14c-bumetanide in the rat and their excretion by rats and dogs. | unchanged bumetanide, 3-(n-butylamino)-4-phenoxy-5-sulfamoylbenzoic acid, and five metabolites were excreted in the urine of rats given 50 mg of 14c-labeled drug per kg intravenously. the metabolites, which were identified by mass spectrometry and/or nuclear magnetic resonance spectroscopy, arose by metabolic alteration of the n-butyl sidechain. in metabolites i-v, the butylamino group was converted to -nhch2ch2ch2cooh, -nhch2ch2ch2ch2oh,, -nhch2ch2chohch3, -nhch2ch2chohch2oh and -nh2, respectiv ... | 1976 | 5262 |
| identification of 5-hydroxybenzimidazole as a major urinary metabolite of benzimidazole in the rat. | | 1976 | 5263 |
| reconstituted liver microsomal enzyme system that hydroxylates drugs, other foreign compounds, and endogenous substrates. ix. the formation of a 455-nm metabolite-cytochrome p-450 complex. | the reconstituted liver microsomal hydroxylation system was used to study the formation of a metabolite-cytochrome p-450 complex absorbing maximally at 455 nm, with benzphetamine and n-hydroxyamphetamine as substrates. complex formation required the presence of nadph, substrate, nadph-cytochrome c reductase, lipid, and cytochrome p-450, indicating that metabolism of the substrate is essential. in the presence of fixed amounts of lipid and nadph-cytochrome c reductase, the rate of complex formati ... | 1976 | 5265 |
| glutathione s-aryltransferase as a model for the glutathione s-transferases. | | 1975 | 5274 |
| perspectives in cancer research. autologous marrow support and intensive chemotherapy in cancer patients. | | 1976 | 5276 |
| mitigation of graft-versus-host disease in rats treated with allogeneic and xenogeneic antilymphocytic sera. | | 1976 | 5281 |
| a simple membrane oxygenator for the isolated rat liver perfusion. | | 1976 | 5289 |
| effect of sympatholytics and beta-adrenoblockaders on the glycogen content in the myocardium of rats of different ages. | | 1976 | 5292 |
| isozymes of amp deaminase in red and white skeletal muscles. | | 1975 | 5297 |