| the specificity of binding of the narcotic agonist etorphine in synaptic membranes of rat brain in vivo. | when 3h-etorphine was administered to rats in a pharmacologically effective dose (0.75 mug/kg intracisternally), the labeled drug was concentrated in synaptic membrane fractions isolated from the brains of rats killed 10 min after etorphine injection. pretreatment of the animals with the narcotic antagonists naloxone, diprenorphine or l-cyclorphan, blocked the pharmacological responses to etorphine and reduced 3h-etorphine binding in the membrane fractions. the differences between 3h-etorphine b ... | 1975 | 707 |
| effects of chronic exposure to stressors on avoidance-escape behavior and on brain norepinephrine. | a single exposure to a severe stressor (either cold swim or inescapable shock) impairs subsequent performance in a shuttle avoidance-escape task (1), a deficit attributed to reduction in brain noradrenergic activity produced by these stressors. in the present paper, two experiments are described which examine how repeated exposure to such stressors affects (a) shuttle avoidance-escape performance (experiment 1), and (b) aspects of brain norepinephrine metabolism (experiment 2). experiment 1 show ... | 1975 | 711 |
| molecular mechanisms in the receptor-mediated regulation of tyrosine hydroxylase. | | 1975 | 712 |
| behavior analysis of the effects and mechanisms of action of benzodiazepines. | | 1975 | 718 |
| the possible involvement of gaba mechanisms in the action of benzodiazepines on central catecholamine neurons. | | 1975 | 719 |
| involvement of gaba in the action of benzodiazepine--studies on rat cerebellum. | | 1975 | 721 |
| behavioral effects of hypothalamic releasing hormones in animals and men. | | 1975 | 729 |
| prolyl-leucyl-glycine amide (plg) and thyrotropin-releasing hormone (trh): dopa potentiation and biogenic amine studies. | | 1975 | 730 |
| the renin-angiotensin system and drinking behavior. | | 1975 | 732 |
| neurotransmitters and temperature regulation. | | 1975 | 733 |
| delta-9-tetrahydrocannabinol action and neuronal membrane-bound enzymes. | | 1975 | 735 |
| modification of in vitro neurotransmitter release from rat brain slices by hypophyseotropic factors. | | 1975 | 736 |
| role of cardiovascular and ionic changes in pathogenesis and prevention of isoprenaline-induced cardiac necrosis. | blood pressure, heart rate, oxygen uptake, and blood values of po2, pco2, and ph were studied in unanesthetized rats for 8 hours. after a cardiotoxic dose of 20 mg/kg isoprenaline, s.c., blood pressure fell from 117 to 72 mm hg, heart rate accelerated from 326 to 497 beats/minute, and cardiac work diminished by about 15%. metabolic rate increased by about 80%, blood values of po2 rose, and those of pco2 fell somewhat, whereas blood ph dropped from 7.48 to 7.38, indicating metabolic acidosis. pro ... | 1975 | 741 |
| alterations in norepinephrine pattern in the damaged myocardium in the rat. | in the albino rat, the evolvement of myocardial necrosis induced by a single injection of iso was accompanied by a fall in total ne. pretreatment with propranolol and pargyline protected against iso-induced necrosis and myocardial hypertrophy, but did not influence the iso-induced depletion of ne stores. the depletion of ne stores is not due to impairment in synthesis or increased intraneuronal metabolism of ne since, in iso-treated rats, neither cardiac tyrosine hydroxylase activity nor mao act ... | 1975 | 742 |
| prevention of myocardial ca overload and necrotization by mg and k salts or acidosis. | the crucial point in the pathogenesis of isoproterenol-induced myocardial necrotization is an abundant intracellular ca accumulation leading to high energy phosphate exhaustion. accordingly, in the early stage of the isoproterenol-induced necrotization process, the onset of atp and creatine phosphate breakdown strictly parallels the acute ca gain. in this type of necrosis, the mg losses from the myocardium appear as a concomitant phenomenon. the hearts can be protected against the deleterious ca ... | 1975 | 743 |
| explanation of the stimulation of microsomal n-demethylation reactions by soluble supernatant fraction. | addition of the cell soluble supernatant fraction to an assay medium containing nadph generating system, mixed function oxidase substrate and microsomes, resulted in a stimulation of drug metabolism ranging from 12-75%. this stimulation was observed only when the supply of dadph generating system (isocitric dehydrogenase or glucose 6 phosphate dehydrogenase) was insufficient, leading to a nadph oxidation rate which was greater than the rate of reduction of nadp+ during the oxidation of a drug. h ... | 1975 | 745 |
| an attempt to correlated analgesia to changes in brain neuromediators in rats. | the analgesic activity of delta9thc, morphine and sodium salicylate was studied concomitantly with changes in brain stem levels of 5ht, 5hiaa, da and na. the results show that a correlation exists between analgesia and changes in the serotonergic system of the brain stem. furthermore morphine sulfate was found to increase the da concentration of the brain stem while delta9thc increased na levels. we conclude that serotonergic system may be of major importance in analgesia while simultaneous chan ... | 1975 | 746 |
| colorimetric determination of 5-aminosalicylic acid and its n-acetylated metabolite on urine and feces. | a simple and convenient colorimetric method is described for the quantitative determination of 5-aminosalicylic acid (5-asa) and n-acetyl-5-asa in urine and feces after oral administration of salicylazosulfa-pyridine (sasp), the drug of choice in the treatment of ulcerative colitis. n-acetyl-5-asa is extracted directly from the acidified biological specimen, deacetylated, and the liberated 5-asa subjected to a modified bratton-marshall reaction. the 5-asa present in the specimen must be acetylat ... | 1975 | 747 |
| determination of inorganic pyrophosphatase in rat odontoblast layer by a radiochemical method. | the enzyme inorganic pyrophosphatase (ppiase, ec 3.6.1.1) from the odontoblastic layer of rat incisors has been studied by means of a radiochemical micromethod. the enzyme was incubated with 32p-pyrophosphate in tris-hcl buffer at 37 degrees c. the reaction was linear with time for at least 45 min, and the ph optimum was found to be 8.8, independent of the amount of pyrophosphate present. heating the enzyme at 56 degrees c inhibited the enzyme activity rapidly, mg2+ ions activated the enzyme by ... | 1975 | 784 |
| experimental methanol toxicity in the primate: analysis of metabolic acidosis. | | 1975 | 819 |
| separation of the hormones of the adenohypophysis of rats by use of electrophoresis in polyacrylamide gel in the presence of sodium dodecyl sulfate. | a comparative study of rat adenohypophysis extract and its alcohol fractions was performed by two variants of the method of electrophoresis in polyacrylamide gel: at ph 9,5 and with the presence of sodium dodecyl sulphate at ph 7.2. with the presence of sodium dodecylsulphate four protein zones are found which in the order from the anode towards the cathode are identified as hemoglobin, somatotropin, lactotropin and albumin. it is shown that the somatotropin zone after the extract separation at ... | 1975 | 829 |
| properties of nad-glycohydrolase of the nuclei of the liver cells of rats. | certain properties of the rat liver cell nuclei nad-glycohydrolase (ec 3.2.2.5) were investigated. it is established that its highest activity is at 37 degrees with activation energy equal to 9480 cal/m and with factor q10 equal to 1.5. the enzyme ph optimum in 0.2 m tris acetate is equal to 6.5 and in 0.2 potassium phosphate - 7.5. it was shown that the enzyme manifests its strict specificity only with beta-nad, and it hardly decomposes nadp without affecting nadh, nadph and nmn. the apparent k ... | 1975 | 830 |
| properties of glutamine synthetase of the brain of rats during ontogenesis. | when investigating activity of glutamine synthetase of the enzymatic preparations isolated from the brain of rats of 0.5, 1, 3, 12 and 24-month age, no considerable differences were found in the indices of the values km to a-glutamate and vmax which are respectively equal to: km (m-10(-3))=5.5; 3.5; 3.6; 3.9; 5.5; vmax=3.1; 4.5; 5.0; 5.2 mum were found. when adding various concentrations of a-ketoglutaric acid into the incubation medium the differences are registered in the degree and character ... | 1975 | 832 |
| experimental ulcer. | | 1975 | 855 |
| absorption of short and medium chain fatty acids in the jejunum of the rat. | the uptake of the shortest six fatty acids (acetic to octanoic) was studied in vitro, using everted segments of rat jejunum. the marked influence of medium-ph and fatty acid chain-length suggests that non-ionic diffusion through the lipoid membrane is quantitatively the most important way of transport, but ionic diffusion through the membrane as well as transport through hydrophilic pores also seem to play a role. though fatt acids evidently are accumulated in the tissue-fluid, and saturation ki ... | 1975 | 860 |
| proceedings: intracellular ph and co2-binding curve of the myocardium in normo and hyperthermia in rats. | | 1975 | 862 |
| different influence of the semicastration and of unilateral cryptorchism on the controlateral testis. | | 1975 | 866 |
| sympathico-adrenal system activity in a primary immune response. | experiments were carried out on linear mice immunized with sheep erythrocytes; it was found that the primary immune respose developed against the background of significant changes in the state of the sympathico-adrenal system, whose activity was determined by the dynamics of catecholamines in the blood and in the tissues of a number of organs, including the thymus, the spleen and the lymph nodes. by comparing the value of specific and neurohumoral indices it was revealed that the neurohumoral sh ... | 1975 | 877 |
| sex as a factor in metabolism, toxicity, and efficacy of pharmacodynamic and chemotherapeutic agents. | | 1975 | 901 |
| effect of amphetamine-type psychostimulants on brain metabolism. | | 1975 | 902 |
| ionic requirements of proximal tubular sodium transport. ii. hydrogen ion. | simultaneous perfusion to proximal convoluted tubules and peritubular capillaries was used to study the effects of different perfusion fluids on sodium reabsorption and hydrogen secretion, which was calculated as bicarbonate reabsorption and titratable acid. results show that sodium reabsorption was not tightly coupled to hydrogen secretion. bicarbonate stimulates both sodium reabsorption and hydrogen secretion, but tris stimulates only sodium reabsorption. imposing an adverse chloride gradient ... | 1975 | 909 |
| separation of low molecular weight rna by polyacrylamide gel electrophoresis. | | 1975 | 925 |
| protective effect of hypothermia in cerebral oxygen deficiency caused by arterial hypoxia. | to study the cerebral protective effects of hypothermia in arterial hypoxia, anesthetized (70% n2o), mechanically ventilated rats were cooled to a body temperature of 27 c. hypoxia was induced by decreasing the oxygen content in the inspired gas mixture either to 6-7 per cent or to 2.5-3 per cent. this reduced mean pao2 to about 25 and 11-12 torr, respectively. at pao2 torr, there was no change in cerebral blood flow (cbf), cerebrla oxygen consumption (cmro2), or labile tissue metabolites. the a ... | 1976 | 930 |
| ascorbic acid and biological systems. ascorbic acid and electron transport. | | 1975 | 941 |
| carcinofetal alterations in glucosamine-6-phosphate synthetase. | the levels of glucosamine-6-phosphate synthetase in various rat tissues including those undergoing differentiation or regeneration revealed that the enzyme is related to tissue proliferation and differentiation. in the liver upon neoplastic transformation, the level of glucosamine 6-phosphate synthetase rises and the liver form of the enzyme having a pi at 5.0 is replaced by a form with a pi of 4.1. since the latter form has also been found present in whole embryos (12- and 14-day) and brain, th ... | 1975 | 947 |
| reduced nicotinamide adenine dinucleotide phosphate (nadph)-dependent formation and breakdown of hydrogen peroxide during mixed function oxidation reactions in liver microsomes. | | 1975 | 955 |
| mixed function oxidation of hexobarbital and generation of nadph by the hexose monophosphate shunt in isolated rat liver cells. | | 1975 | 956 |
| a polydeoxythymidylic acid-specific deoxyribonuclease from rat ascites hepatoma cells. | | 1975 | 964 |
| inhibition by lipoperoxidation of amino acid incorporation by rough microsomal membranes in vitro and its partial reversibility. | | 1975 | 969 |
| tumour hyperacidulation through intravenous glucose infusion enhanced by amygdalin and beta-glucosidase application (author's transl). | tumour peracidity in otherwise moderately hyperacidulated tumours or tumour regions of ds carcinosarcoma-bearing wistar rats attained by glucose infusion was substantially increased by simultaneous infusion of amygdalin and intratumoral i.m. or i.v. application of beta-glucosidase. here the ph value of healthy tissue, measured at the sceletal muscle, remained unchanged. by means of the said process, tumour hyperacidulation has been raised to a level of deltaph =0.97; attaining a ph difference be ... | 1975 | 979 |
| the effects of acute and chronic nicotine hydrogen (+)-tartrate administration and subsequent withdrawal on rat liver tryptophan pyrrolase activity and their comparison with those of morphine, phenobarbitone and ethanol. | acute administration of nicotine hydrogen (+)-tartrate enhances the activity of rat liver tryptophan pyrrolase by a hormonal mechanism. chronic nicotine treatment inhibits, and subsequent withdrawal enhances, the pyrrolase activity. the inhibition during chronic treatment is not due to a defective apoenzyme synthesis nor a decreased cofactor availability. regeneration of liver nadp+ in vitro and in vivo reverses the inhibition. chronic nicotine administration increases the liver nadph concentrat ... | 1975 | 989 |
| activities of citrate synthase, nad+-linked and nadp+-linked isocitrate dehydrogenases, glutamate dehydrogenase, aspartate aminotransferase and alanine aminotransferase in nervous tissues from vertebrates and invertebrates. | 1. the activities of citrate synthase and nad+-linked and nadp+-linked isocitrate dehydrogenases were measured in nervous tissue from different animals in an attempt to provide more information about the citric acid cycle in this tissue. in higher animals the activities of citrate synthase are greater than the sum of activities of the isocitrate dehydrogenases, whereas they are similar in nervous tissues from the lower animals. this suggests that in higher animals the isocitrate dehydrogenase re ... | 1975 | 1003 |
| amp-deaminase of human skeletal muscle. divalent metal cations and catalytic activity. | | 1975 | 1005 |
| the attachment of glutamine synthetase to brain membranes. | | 1975 | 1006 |
| tetrahydropterin: reduction of cytochrome c and coupled phosphorylation at mitochondrial site 3. | | 1975 | 1011 |
| a heparan sulfate-degrading endoglycosidase from rat liver tissue. | | 1975 | 1035 |
| thermographic and histologic studies of the antiinflammatory effect of benorilate by means of the cotton pellet test in the rat (author's transl). | 1. the effect of (4-acetamido-phenyl)-2-acetoxy-benzoate (benorilate, benortan) on the inflammatory process was studied thermographically and histologically in cotton-pellet tests on rats. 2. following implantation of the cotton-pellet, thermography shows a clear inhibition of the local inflammation due to treatment with benorilate. 3. histological examination shows a corresponding influence of benorilate upon the proliferative phase of the inflammation. 4. the success of antiphlogistic therapy ... | 1975 | 1041 |
| acidic antiinflammatory agents--correlations of some physical, pharmacological and clinical data. | fifteen acidic antiinflammatory agents, for which some clinical data have previously been published, have been examined for their potency in the carrageenan-induced rat foot edema test, and for their acidity (pka) and partition coefficients. published serum half-life data and daily clinical (anti-arthritic) dose have been tabulated for these drugs and correlations between these various parameters are discussed. the rat foot edema carrageenan test has proved to be a fairly reliable predictor of c ... | 1975 | 1042 |
| flavoxate and 3-methylflavone-8-carboxylic acid. assay methods in blood and urine, plasma-red cells repartition and stability. | the following assay methods for pharmacokinetic studies on flavoxate (f) and on its main metabolite, i.e. 3-methylflavone-8-carboxylic acid (a), are described. 1. spectrophotometry for the assay of f and of a in plasma, 2. tlc-spectrodensitometry and glc for the assay of a in urine after acid hydrolysis, 3. tlc-spectrodensitometry for determining the f : a ratio in plasma or in urine. it was found that f hydrolyzes into a. this process depends on the ph and on the medium. in water, at ph 5.0, f ... | 1975 | 1048 |
| on the pharmacology of 9,10-dihydro-10-(1-methyl-4-piperidylidene)-9-anthrol (wa 335), a histamine and serotonin antagonist (author's transl). | the substance 9,10-dihydro-10-(1-methyl-4-piperidylidene)-9-anthrol (wa 335) was examined for its antagonistic effects against histamine and serotonin, for its atropine-like properties as well as for a series of other qualities in comparison with cyproheptadine and pimethixene. the anti-histamine and anti-serotonin activities of compound wa 335 on the smooth muscle and the capillary do not only exceed that of cyproheptadine but also that of pimethixene. wa 335 shows an extremely strong binding t ... | 1975 | 1049 |
| central action of wa-335-bs, a substance with peripheral antiserotonin and antihistaminic activity. | in rats and mice the serotonin and histamine antagonistic drug 9,10-dihydro-10-(1-methyl-4-piperidylidene)-9-anthrol (wa 335-bs) caused stronger central sedative effects than did cyproheptadine. wa 335-bs also displayed stronger activity against reserpine- and central tremorine-induced effects than did cyproheptadine and it slightly enhanced d-amphetamine-induced effects: therefore it may have antidepressant properties. wa 335-bs proved to be very effective against isolation-induced aggression i ... | 1975 | 1050 |
| the distribution and elimination of radioactivity in the rat after administration of 14c-4-acetamidophenyl-2-acetoxybenzoate (benorylate). | following oral administration of 4-acetamido-phenyl-2-acetoxybenzoate (carboxyl-14c) (benorylate) to rats, no gross differences were detected 7.5 h after administration with respect to the distribution of 14c in various tissues, including the upper sections of the small intestine. a high concentration of 14c was found in the lower sections of the intestine 4 h after administration. the 14c in the intestine was present as unchanged benorylate, as detected by thin-layer chromatography, suggesting ... | 1975 | 1051 |
| antisecretory and anti-gastric ulcer activity of a tranquilizing-parasympatholytic combination. | | 1975 | 1077 |
| absorption of rat liver ribosomal ribonucleic acids on agar gels. | | 1975 | 1102 |
| the fragmentation and reconstruction of the oligomycin-sensitive atpase system of liver mitochondria. | the protein and proteolipid complexes and oligomycin insensitive soluble atpase were prepared from rat liver mitochondria. the incubation of soluble atpase with protein and proteolipid complexes resulted in restoration of atpase sensitivity to oligomycin at room temperature. the process of reconstruction depended on ph, incubation time, temperature and other conditions. | 1975 | 1103 |
| activity of polynucleotide phosphorylase in ribosomal fraction of rat liver. | a method of isolating polynucleotidephosphorylase (pnpase) containing polyribosome fraction from rat liver is described. pnpase is found to be bind to rna in polyribosomes with weak electrostatic bonds which are easily broken down in a weak alkaline medium with ionic strength more than 0.1 beta-22p-labelled adp, gdp, udp and cdp are found among the products of endogenous rna degradation in the fraction of total polyribosomes in the presence of 32p-orthophosphate. a considerable change in the bas ... | 1975 | 1115 |
| modification of michael's method for determination of serum acetyl choline esterase activity. | | 1975 | 1129 |
| trans-synaptic regulation of the development of end organ innervation by sympathetic neurons. | to examine the regulation of development of end organ innervation the superior cervical ganglion (scg), and two of its target organs, the iris and pineal gland, were studied using biochemical and histofluorescent approaches. during postnatal ontogeny the activity of tyrosine hydroxylase (t-oh), which is localized to adrenergic neurons, increased 50-fold in iris, and 34-fold in pineal nerve terminals of the rat. these increases paralleled the in vitro rise in iris 3hnorepinephrine (3hne) uptake, ... | 1976 | 1141 |
| mechanism of action of mg2+ and zn2+ on rat placental alkaline phosphatase. i. studies on the soluble zn2+ and mg2+ alkaline phosphatases. | rat placental alkaline phosphatase (ec 3.1.3.1), a dimer of 135,000 daltons, is strongly activated by mg2+. however, zn2+ has to be present on the apoenzyme to obtain this activation. mg2+ alone is unable to reconstitute functional active sites. excess zn2+ which competes for the mg2+ site leads to a phosphatase with little catalytic activity at alkaline ph but with normal active sites at acidic ph as shown by covalent incorporation of ortho-32pphosphate. two enzyme species with identical functi ... | 1975 | 1142 |
| l-alphas, 5s-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid (nsc-163501): a new amino acid antibiotic with the properties of an antagonist of l-glutamine. | l-alphas,5s-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid (nsc-163501), an antibiotic elaborated by streptomyces sviceus, has been shown to be a powerful inhibitor of many mammalian and bacterial reactions involving the transfer of nitrogen from the gamma-carboxamide of l-glutamine. thus, the utilization of l-glutamine for the synthesis of carbamyl phosphate, l-asparagine, guanosine-5'-monophosphate, cytidine-5'-triphosphate, n-formylglycinamidine ribonucleotide, nad, glucosamine-6-pho ... | 1975 | 1147 |
| evidence for a physiological role of renal sympathetic nerves in adrenergic stimulation of renin release in the rat. | previous studies on renin release by an in vitro system of rat kidney slices, which is devoid of hemodynamic influences, have provided evidence that renin release is stimulated by a beta-adrenergic mechanism. we used this system to study effects of tyramine (an indirectly acting amine capable of displacing endogenous catecholmines from sympathetic nerve endings) on renin release. tyramine (10(-3)m) in the presence of a monoamine oxidase inhibitor (pheniprazine, 10(-5)m) and a phosphodiesterase i ... | 1976 | 1155 |
| properties of beta-glucuronidase activity in human synovial fluid. | the purpose of the present study was to evaluate the properties of beta-glucuronidase (ec 3.2.1.31) in human synovial fluid. it was shown to have a ph requirement of 5.0 and a km value of about 8.0 - 10(-3) m using phenolphthalein beta-glucuronide as the substrate. at low substrate concentration an endogenous inhibitor is demonstrable. the inhibition is of the competitive type and is removed by proteolytic digestion of synovial fluid, whereas hyaluronidase digestion and addition either of triton ... | 1975 | 1163 |
| the effect of host adrenalectomy on the physiology of trypanosoma rhodesiense. | | 1975 | 1186 |
| intestinal absorption of amino acids in rats infected with nematospiroides dubius. | | 1975 | 1197 |
| body temperatures and heart rates of laboratory rats and belding squirrels (spermophilus beldingi) during behavioral thermoregulation. | | 1975 | 1199 |
| the role of the tail in temperature regulation of the cotton rat, sigmodon hispidus. | | 1975 | 1200 |
| tissue metabolites of trifluorperazine, fluphenazine, prochlorperazine, and perphenazine. kinetics in chronic treatment. | repeated oral treatment of male rats with piperazine-substituted phenothiazine drugs in doses of 25 mg/kg or more daily led to an accumulation of metabolites containing an ethylenediamine group instead of the piperazine ring. these products of ring degradation with and without removal of the n-alkyl group were found, together with the parent drugs and their n-dealkylated metabolites, in liver, lung, kidney, and spleen, as well as in brain when high doses were administered. after termination of t ... | 1975 | 1218 |
| comparative biotransformation of triflubazam in rats, dogs, and monkeys. | the biotransformation of 14c-triflubazam (orf 8063; 1-methyl-5-phenyl-7-trifluoromethyl-1h-1,5-benzodiazepin-2-4-3h,5h-dione) was investigated in rats, dogs, and monkeys. urinary metabolites, representing 65, 74, and 87%, respectively, of the total urinary radioactivity excreted by these three species, were isolated by preparative layer chromatography and characterized by various spectral techniques including gas chromatography/mass spectrometry, solid probe mass spectrometry, polarimetry, and i ... | 1975 | 1219 |
| physiological disposition and metabolism of 5-(2',4'-difluorophenyl)salicyclic acid, a new salicylate. | 5-(2'4'-difluorophenyl) carboxy-14csalicyclic acid (mk-647) was quickly and completely absorbed in rats, dogs, and man. peak levels of plasma radioactivity occurred in 1-2 hr after oral administration. the dose was 10 mg/kg in rats and dogs, and 50 or 500 mg in man. most of the drug in plasma was intact mk-647 which was extensively bound to plasma protein. in man the peak concentration following the 500-mg dose was approximately 10 times that after the lower dose, which suggests that absorption ... | 1975 | 1220 |
| correlation of 14c-griseofulvin metabolism in rat liver microsomes, isolated perfused rat livers, and in rats with bile duct cannulas. | the metabolism of 14c-griseofulvin has been compared in rat liver microsomes, isolated perfused rat livers, and rats with bile duct cannulas. in all three preparations, 4-desmethylgriseofulvin and 6-desmethylgriseofulvin were the major metabolites. the ratio of total 4-desmethylgriseofulvin to 6-desmethylgriseofulvin formed was 1.20, 0.89, and 1.01 in liver microsomes, isolated perfused livers, and rats with bile duct cannulas, respectively. after a 7-min incubation with liver microsomes, most ( ... | 1975 | 1223 |
| oxidative biotransformation of 2-acetylaminofluorene in fetal and placental tissues of humans and monkeys. correlations with aryl hydrocarbon hydroxylase activities. | the mixed-function oxidation of 14c-labled 2-acetylaminofluorene (aaf) was investigated in placental and fetal tissues of humans and monkeys (macaca nemestrina) in vitro. the major metabolite formed in most tissues was 7-hydroxy-aaf. rates of the hydroxylation reactions varied widely among the tissues investigated and were generally one to two orders of magnitude lower than those measured in rat hepatic tissues. high correlations among rates of 7-,5-, and 3- and between 1- and n-hydroxylations o ... | 1975 | 1224 |
| further studies of metyrapone effects upon anilide hydroxylation. | the enhancing effect of metyrapone upon the p-hydroxylation of acetanilide has been confirmed with the use of a new gas-chromatographic method for the determination of acetaminophen. this effect has been shown not to be due to inhibition of hydrolysis of acetaminophen or interference with its determination, or to preferential formation of other phenolic metabolites. this effect of metyrapone is remarkably substrate-specific: phenol formation from the homologues of acetanilide, formanilide and pr ... | 1975 | 1226 |
| nature and fate of insecticide residues inhaled by rats in cigarette smoke. | radioactive carbaryl, carbofuran, parathion, leptophos, and ddt were added to cigarettes and the mainstream smoke was directed to the lungs of rats via the trachea. total radiocarbon transfer to the lungs ranged from 9 to 15% of that in the tobacco burned during a smoking process involving eight 5-ml puffs. exhalation of 14c residues during this time was 24 to 30% of that inhaled with all insecticides except carbofuran, of which 42% of the residues was exhaled. after 5 hr, total exhalation of th ... | 1975 | 1227 |
| absorption and disposition of 2-4-(2,2-dichlorocyclopropyl)phenoxy-2-methylpropanoic acid, win 35,833, in rats, monkeys, and men. | 2-4-(2,2-dichlorocyclopropyl)phenoxy-2-methylpropanoic acid, win 35,833, was readily absorbed after oral administration; in rats, rhesus monkeys, and human volunteers, peak concentrations of drug in plasma were attained within 2 hr of medication. the time-concentration curve of administered drug was biphasic in monkeys and men, while in rats the kinetics of a one-compartment model were observed. distribution studies of 14c-labeled drug in the rat showed that most of the radioactivity was excrete ... | 1975 | 1228 |
| the gastrointestinal absorption of methadone in the rat. | the absorption of dl-methadone from the gastrointestinal tract of the sprague-dawley rat was examined by the in vivo segment technique. duodenal absorption, measured as a function of time and dose, followed first-order kinetics with a half-life of 15.6 min. absorption was not influenced by prior or concomitant administration of a variety of drugs. absorption from other regions of the intestine was similar to that from the duodenum; in contrast, absorption from the stomach was markedly slower. ga ... | 1975 | 1229 |
| biliary excretion of colchicine in newborn rats. | the 24-hr ld50 of colchicine in newborn rats is 0.24 mg/kg, which is about 1/10 that observed in the adult. the 24-hr ld50 of colchicine was relatively constant in rats over 25 days of age. in an attempt to determine the mechanism of the increased sensitivity of the newborn rat to the toxic action of colchicine, the distribution of 3h after the administration of 3h-colchicine (0.1 mg/kg) was measured in 10- and 35-day-old rats. the concentration of 3h was higher in all tissues of the newborn tha ... | 1975 | 1230 |
| disposition in rats of a polyoxypropylene-polyoxyethylene copolymer used in plasma fractionation. | a polyoxypropylene-polyoxyethylene block copolymer of about 4750 daltons (poloxamer 108, pluronic f-38) used in a new protein fractionation procedure may be infused into patients receiving therapeutic plasma fractions. we studied the disposition and pharmacokinetics of poloxamer 108 in rats as an initial step towards understanding its behavior in man. after iv administration in rats, about 94% of 7 or 100 mg/kg doses of ethylene-14c-labeled polymer was excreted in the urine in 3 days. about 6% o ... | 1975 | 1231 |
| kinetic and spectral studies of type i and type ii compounds with rat hepatic microsomes in the presence of the major metabolite of diphenylhydantoin. | the nature of the inhibitory effects of the major metabolite of diphenylhydantoin, 5-(p-hydroxyphenyl)-5-phenylhydantoin (hpph), on the in vitro metabolism of ethylmorphine and aniline by rat hepatic microsomes was examined. the n-demethylation of ethylmorphine was competitively inhibited by hpph, whereas inhibition of the hydroxylation of aniline was not competitive. the spectrum produced by hpph when added to microsomal suspensions does not resemble the classical type i or type ii spectra, but ... | 1975 | 1233 |
| change in the kinetics of sulphacetamide tissue distribution in walker tumor-bearing rats. | the effect of walker tumor on sulphacetamide distribution was studied in rats 21 days after tumor implantation in a hind leg. after oral administration of sulphacetamide (5 and 20 min), the concentration of the drug was found to be lower in the plasma and liver of tumor-bearing rats when compared with that of control group. however, 90 min after sulphacetamide administration, the concentration of the drug in these same tissues was found to be higher in tumor-bearing rats than in control animals. ... | 1975 | 1234 |
| cytochrome p-450 measurement in rat liver homogenate and microsomes. its use for correction of microsomal losses incurred by differential centrifugation. | cytochrome p-450 was assayed in rat liver homogenates and microsomes in order to calculate microsomal recoveries and correct for losses during ultracentrifugation or sedimentation in presence of cacl2. the values obtained for corrected microsomal protein in untreated female sprague-dawley rats were between 40 and 50 mg/g of liver. the assay of cytochrome p-450 in liver homogenate is accurate enough to calculate a reproducible recovery factor. the value of the method lies in its rapidity, its cap ... | 1975 | 1235 |
| further studies on lipid-peroxide formation in isolated hepatocytes. | lipid peroxide formation was initiated by the addition of either adp-complexed fe3+ or cumene hydroperoxide to a suspension of isolated hepatocytes. the reaction was monitored by malonaldehyde measurements. upon the addition of iron, malonaldehyde production in the cells started immediately but ceased within 30-60 min, and the response was dose-related with iron concentrations ranging from 19 to 187 mum. malonaldehyde formation was associated with increased oxygen uptake and conjugated diene pro ... | 1975 | 1255 |
| multiple forms of human glutathione s-transferase and their affinity for bilirubin. | the initial enzymic step in mercapturic acid formation is catalyzed by glutathione s-transferase. several species of this enzyme, designated as transferases alpha, beta, gamma, delta and epsilon on the basis of increasing isoelectric points, were isolated from human liver. evidence is presented that each of the purified species is homogeneous with respect to sodium dodecylsulfate-gel electrophoresis. transferases alpha, beta and epsilon each appear as a single band on gel electrofocusing; transf ... | 1975 | 1262 |
| cytochrome c interaction with membranes. absorption and emission spectra and binding characteristics of iron-free cytochrome c. | a cytochrome c derivative from which iron is removed has been prepared and characterized. several lines of evidence indicate that native and porphyrin cytochrome c have similar conformations: they have similar elution characteristics on sephadex gel chromatography; in both proteins the tryptophan fluorescence is quenched and the pk values of protonation of the porphyrin are identical. porphyrin cytochrome c does not substitute for native cytochrome c in either the oxidase reaction or in restorin ... | 1975 | 1265 |
| acetylglucagon: preparation and characterization. | acetylated derivatives of glucagon have been prepared by reacting this hormone under various conditions with acetic anhydride. they have been chemically characterized by the use of a 14c-labeled reagent, by peptide mapping techniques following hydrolysis by pronase and chymotrypsin, and by spectroscopy. acetylation in sodium acetate (ph 5.5) results in a full substitution of the alpha-amino group of the n-terminal histidyl residue, but in a partial (about 0.3 acetyl group per residue) substituti ... | 1975 | 1270 |
| hepatic nucleases. extrahepatic origin and association of neutral liver ribonuclease with lysosomes. | in the large granule fraction of rat liver, the density distribution of inhibitor-sensitive neutral ribonuclease is similar to that for acid hydrolases and its density distribution is similarly modified by triton wr-1339 accumulation in lysosomes. particulate neutral ribonuclease is latent; the enzyme is unmasked by very low digitonin concentrations or hypoosmotic shock. these observations demonstrate that the bulk of liver neutral ribonuclease is associated with the lysosomal system. in view of ... | 1975 | 1273 |
| pyrophosphatase and glucuronosyltransferase in microsomal udpglucuronic-acid metabolism in the rat liver. | 1. a radiochemical method for the studies on the microsomal udpglucuronic acid metabolism has been developed. 2. the rat liver microsomes caused a rapid hydrolysis of udpglucuronic acid to d-glucuronic acid 1-phosphate and further although much slower to free d-glucuronic acid. in tris-hcl buffer (ph 7.4) they were produced in ratio 72 : 1. no other metabolites were found in measurable amounts. the pyrophosphatase splitting udpglucuronic acid showed a ph optimum at 8.9, but the liberation of d-g ... | 1976 | 1276 |
| incorporation of (1-14c)palmitoyl-coa into phosphatidylcholine by plasma membranes of rat submaxillary glands in vitro. | 1. on incubation with the isolated rat submaxillary gland plasma membranes, 1-14cpalmitoyl-coa was incorporated mainly into phosphatidylcholine and hydrolysed to 1-14cpalmitic acid and coash. 2. the addition of lysophosphatidylcholine enhanced the incorporation into phosphatidylcholine and lowered the hydrolysis of palmitoyl-coa markedly. 3. in the presence of lysophosphatidylcholine, palmitoyl-coa incorporation into phosphatidylcholine was maximum at 0.1 mm palmitoyl-coa, 0.5 mm lysophosphatidy ... | 1976 | 1278 |
| hemodynamics and its regulation in old age. | | 1975 | 1284 |
| altered responsiveness of adenosine 3',5'-monophosphate-generating systems in rat cortical slices after lesions of the medial forebran bundle. | | 1975 | 1285 |
| impaired sertoli cell function in experimental cryptorchidism in the rat. | the production of testicular androgen-binding protein (abp), as a measure of sertoli cell function, was studied after unilateral or bilateral experimental cryptorchidism in adult rats. two or 4 weeks after the testis had been translocated to the abdomen, no major changes were found in the concentration of abp per mg protein, although there was a marked and progressive decrease in abp content per testis. however, the rate of abp production was greatly decreased, as measured by the accumulation of ... | 1975 | 1296 |
| aminoacyl-trna binding activity in regenerating kidney following contralateral nephrectomy or administration of folic acid. | | 1975 | 1297 |
| further investigations with ph microelectrodes into the jejunal microclimate in rat and man. | | 1975 | 1331 |
| purine nucleotide cycle. evidence for the occurrence of the cycle in brain. | cell-free extracts of rat brain catalyze the reactions of the purine nucleotide cycle. ammonia is formed during the deamination but not the amination phase of the cycle. the activity of adenylate deaminase in brain is sufficient to account for the maximum rates of ammonia production that have been reported. the activity of glutamate dehydrogenase is not sufficient to account for these rates of ammonia production. the activities of adenylosuccinate synthetase and adenylosuccinase are nearly suffi ... | 1976 | 1396 |
| high-resolution liquid chromatographic analysis of methylated purine and pyrimidine bases in transfer rna. | methylated and major purine and pyrimidine bases were separated and quantified by high-resolution liquid chromatography after hydrolyzing transfer ribonucleic acids (trnas). separation was accomplished by eluting the hydrolyzed samples from an anion-exchange column with a concentration gradient of ammonium acetate at ph 9.2. isolated sample of trna were hydrolyzed to the free bases with a trifluoroacetic acid-formic acid mixture of 200 degrees. detection limits of 100-200 ng/ml were measured for ... | 1976 | 1412 |
| specific ion-exchange chromatography and fluorimetric assay for urinary 3-o-methyldopamine. | a technique for the selective extraction of 3-o-methyldopamine, normetanephrine and metanephrine from a single urine sample has been investigated. after hydrolysis of the conjugates, the diluted mixture is passed through a dowex 50w-x2 column and the methoxylated amines are eluted by means of concentrated ammonia. the eluate, containing metanephrine, normetanephrine and 3-o-methyldopamine is evaporated, and a solution of the residue in borate buffer is fractionated under strictly controlled cond ... | 1976 | 1415 |
| analysis of the radioimmunoassay for gonadotropin-releasing hormone (gnrh): studies on the effect of radioiodinated gnrh. | when gnrh is radioiodinated by the chloramine-t method, two immunoreactive labeled species are formed at ph 6.5 with a chloramine-t: gnrh molar ratio of 11:1, whereas four bands (i, iia, iib, and iii) are separated by polyacrylamide gel electrophoresis when the hormone is iodinated at ph 7.5 in a system containing a 97:1 molar ratio of chloramine-t:gnrh. because they were more stable and were more immunoreactive than the other products, band i and band iia from the latter system were used separa ... | 1975 | 1416 |
| the effect of neonatal rat graft-vs-host disease (gvhd) on fc receptor lymphocytes. | the level of fc receptor rosette-forming lymphocytes (fc-rfl) was examined in spleen and lymph node cell suspension from neonatal da and bn rats inoculated within 24 hr of birth with either allogeneic l (experimental) or syngeneic (control) lymphoid cells. in addition, these levels were compared to fetal and neonatal animals that received no injection. the indicator cells (ea) were sheep erythrocytes sensitized with one-half concentration of the highest dilution of rabbit anti-sheep erythrocyte ... | 1976 | 1444 |
| biochemical changes in rat brain associated with the development of the blood-brain barrier. | | 1975 | 1470 |
| studies of the effect of dietary cholesterol on hepatic protein synthesis, reduced glutathione levels and serine dehydratase activity in the rat. | a basal diet or a basal diet plus 1% of cholesterol and 0.33% cholic acid was fed to rats for varying lengths of time and (1) the activities of liver phosphoenolpyruvate-carboxykinase (pep-ck), tyrosine transaminase (tt), and serine dehydratase (sd); (2) the rate of total hepatic protein synthesis and (3) the concentration of hepatic reduced glutathione (gsh) were quantitated. the specific activity of pep-ck was significantly depressed by cholesterol plus cholic acid feeding, while the specific ... | 1976 | 1480 |
| the effect of pancuronium on myocardial contraction and catecholamine metabolism. | the effects of pancuronium bromide infusion on the uptake and release of 14c noradrenaline (14c-na) by the isolated, perfused rat heart and on the chronotropic and inotropic activity of the isolated heart were evaluated. hearts were removed from animals under light ether anaesthesia, transferred to a modified langendorff perfusing apparatus and perfused with krebs-ringer bicarbonate solution at a rate of 5 ml min-1. the effect of pancuronium on the uptake of noradrenaline was determined by perfu ... | 1975 | 1492 |