| the action of a toxin from the sea anemone anemonia sulcata upon mammalian heart muscles. | the cardiac activity of toxin ii, a basic polypeptide (m.w.: 4770) from the sea anemone anemonia sulcata, was investigated in isolated electrically driven guinea-pig and rat auricles, langendorff heart preparations of guinea-pigs and cat heart-lung preparations. low concentrations of toxin ii (2-100 nm) evoked a dose-dependent positive inotropic effect in the three different heart muscle preparations investigated. higher concentrations of toxin ii produced toxic symptoms like contracture and arr ... | 1976 | 12483 |
| antinociceptive activitiy of narcotic agonist and partial agonist analgesics and other agents in the tail-immersion test in mice and rats. | | 1976 | 12485 |
| histamine mediation of nicotine effects on postganglionic sympathetic neuroeffector junctions. | | 1976 | 12486 |
| phenylalanine hydroxylase and tyrosine aminotransferase in human fetal and adult liver. | the mean value of phenylalanine hydroxylase activity in adult human liver was almost twice as high as that in the fetal ones; no consistent variations were seen with sex, fetal age (between the 11th and 22nd week of gestation), or with hours between delivery and death. the tyrosine aminotransferase levels did not correlate with sex, age, or method of abortion; however, they were 5 times higher in the two fetuses which survived for more than 1.5 hr after delivery. the mean concentration of tyrosi ... | 1977 | 12495 |
| failure of parathyroid hormone and cyclic amp to inhibit renal carbonic anhydrase. | it has been suggested that the parathyroid hormone and cyclic amp produce their bicarbonaturic effects through inhibition of renal carbonic anhydrase. in the present study, the incubation of renal carbonic anhydrase with parathyroid hormone or cyclic amp in presence of atp, mg++ and k+ ions, did not produce any inhibition of the enzyme when the ph of the solution was maintained above 7. it is concluded, that parathyroid hormone and cyclic amp produce urinary bicarbonate excretion by a mechanism ... | 1976 | 12496 |
| phosphorus nuclear magnetic resonance studies on normoxic and ischemic cardiac tissue. | the intact heart of a young rat was excised rapidly and cooled to 0 degree c; its energy-rich compounds were examined by 31p fourier transform nuclear magnetic resonance. the heart showed the characteristic spectrum of sugar phosphates, inorganic phosphate, phosphocreatine, and magniesium phates, inorganic phosphate, phosphocreatine, and magnesium atp, characteristics of the energizing state of the nonbeating tissue. warming to 30 degrees c imposes an energy load upon the heart consistent with s ... | 1976 | 12507 |
| proline and glycine uptake by renal brushborder membrane vesicles. | uptake of l-proline and glycine by rat renal brushborder membrane vesicles was seen to be osmotically sensitive, ph dependent,and occurred in the absence of proline and glycine metabolism. the uptake system for proline was na+ gradient dependent, and exhibited a dual system for entry, km1 = 0.067 mm and km2 = 5.26 mm. the uptake of glycine was also na+ gradient dependent, and exhibited a two km system, km1 = 0.22 mm and km2 = 4.00 mm. studies of proline and glycine interactions indicate a shared ... | 1976 | 12509 |
| acute muscle denervation induced by beta-bungarotoxin. | | 1976 | 12515 |
| discriminative stimulus properties of fentanyl and morphine: tolerance and dependence. | using a food-reinforced two-lever operant procedure, rats were trained to discriminate 0.04 mg/kg fentanyl from saline. at different time intervals after the establishment of discriminative responding, stimulus generalization experiments were performed with equivalent dose ranges of fentanyl (0.0025 to 0.02 mg/kg) and morphine (2.5 to 20 mg/kg). it was found that the ed50 values of both compounds for generalization with the narcotic discriminative stimulus complex, did not change over a 4-month ... | 1976 | 12518 |
| psychoactive drug effect on behavioural changes induced by prolonged socio-environmental deprivation in rats. | several so-called 'non-specific' or 'non-drug' factors are known to interfere with the response to psychotropic drug administration. animal emotionality has been reported to change the outcome of psychoactive drug administration, so that the response to a stimulant or depressant drug may considerably change according to the baseline state of activity of the central nervous system. prolonged socio-encironmental deprivation or isolation has been shown to produce in rats three different types of ab ... | 1976 | 12521 |
| amino acid precursors of monoamine neurotransmitters and some factors influencing their supply to the brain. | there is evidence that changes in the concentrations of the monoamine neurotransmitters within the brain are associated with changes in mental processes, with disorders of control of movement and with certain neuropsychiatric diseases. these neurotransmitters are synthesized in the brain from aromatic amino acid precursors that have to be obtained from the circulating blood. in this study some factors which alter the rates of entry of four amino acids (the important neurotransmitter precursors l ... | 1976 | 12522 |
| effects of chlordiazepoxide, ripazepam and d-amphetamine on conditioned acceleration of timing behaviour in rats. | the lever-pressing behaviour of three rats was maintained by a schedule in which food reinforcement was obtained by any response which was emitted at least 15 s after the previous response (drl 15s). when performance on this schedule had stabilised, the animals were presented intermittently with 1-min periods of a white noise stimulus, the termination of which was accompanied by the delivery of a mild electric footshock. this procedure let to reliable increases in response rates furing the stimu ... | 1976 | 12524 |
| action of enpiprazole on emotional behavior induced by hypothalamic stimulation in rats and cats. | action of enpiprazole on emotional behavior elicited by hypothalamic stimulation in rats and cats was investigated and comparisons were made with effects of diazepam. two behavioral patterns were elicited by stimulation of the postero-medial part of the hypothalamus in rats: a food-carrying response beginning with exploratory movement and an analogue of fear. enpiprazole frequently changed the food-carrying response into food-taking response and occasionally analogues of fear into food-carrying ... | 1976 | 12526 |
| single and repeated administration of neuroleptic drugs to rats: effects on striatal dopamine-sensitive adenylate cyclase and locomotor activity produced by tranylcypromine and l-tryptophan or l-dopa. | injection of tranylcypromine and l-tryptophan results in rats displaying behavioural changes including hyperactivity, probably due to stimulation of post-synaptic 5-hydroxytryptamine (5-ht) receptors. increased locomotor activity of a different type is elicited by injection of tranylcypromine and l-dopa, a procedure which increased dopaminergic function in the brain. it has now been demonstrated that the neuroleptic drugs, chlorpromazine, alpha-flupenthixol, haloperidol and spiroperidol block bo ... | 1976 | 12527 |
| effects of pyrroxan and chlordiazepoxide on biogenic amine metabolism in the rat brain. | pyrroxan (20 mg/kg, i.p.), a new potential antianxiety agent, increased brain norepinephrine (ne) turnover in rats, reflecting a possible central alpha-adrenergic receptor blocking activity. in contrast, chlordiazepoxide (20 mg/kg, i.p.), a widely used antianxiety agent, did not alter the ne turnover. pyrroxan did not affect overall da turnover although it did appear to accelerate da turnover initially. the initial potentiation of da turnover may indicate a short-lasting blocking action on da re ... | 1976 | 12528 |
| investigations of the mechanism of central action of kinins. | the effects of kinins on the level of norepinephrine, dopamine, and serotonin and on their metabolites, i.e., normetanephrine, homovanillic acid, and 5-hydroxyindoloacetic acid in the brain tissue divided into cerebellum, corpus striatum, cortex, hippocampus, hypothalamus, medulla oblongata, and midbrain were investigated. it was shown that bradykinin in a dose of 4 mug decreased the content of norepinephrine in corpus striatum, midbrain, and cerebellum. it also decreased the level of dopamine i ... | 1976 | 12529 |
| some aspects of dopamine in the basal ganglia. | | 1976 | 12545 |
| changes in brain catecholamines and spontaneous locomotor activity in response to thyrotropin releasing hormone. | repeated exposure of rats to thyrotropin releasing hormone produced a dose- and time-dependent increase in spontaneous locomotor activity accompanied by an increase in brain stem tyrosine hydroxylase. dopamine levels in cerebral cortex were increased maximally by 34% in animals receiving thyrotropin releasing hormone at a dosage of 2 mg/kg for 10 days. the concentrations of brain stem tyrosine and cerebral cortex norepinephrine remained unaltered in response to thyrotropin releasing hormone tre ... | 1976 | 12549 |
| transferrin and iron uptake by isolated rat liver mitochondria. | isolated rat liver mitochondria accumulate iron from the suspending medium when 59fetransferrin is used as a model compound. the accumulation proceeds by two different mechanisms, i.e. by an energy-independent and an energy-dependent (uncoupler sensitive) mechanism, which have different time, ph, and temperature dependencies. the energy-dependent accumulation, which is inhibited by ruthenium red and sulphydryl reagents, reaches a saturation level of approx. 30 pmoles iron/mg protein during 30 mi ... | 1976 | 12556 |
| 3h-deoxythymidine incorporation in graft-versus-host disease in the norway rat. i. liquid scintillation studies. | graft-versus-host-disease was produced in newborn brown norway (bn) rats with an intravenous (iv) injection of adult allogeneic lewis (l) lymph node cells (experimental) and the response was compared to littermates injected with adult syngeneic bn cells (control). by 4 days the reaction in the spleen of experimental animals was such that the spleen index was 1.70 and 2.58 on day 7, and continued to increase until death. a one hour iv pulse of tritiated deoxythymidine (3hdt) administered to exper ... | 1976 | 12606 |
| 3h-deoxythymidine incorporation in graft-versus-host disease in the norway rat. ii. autoradiographic studies. | a sequential analysis was made of various areas within the lymph nodes and spleen of newborn brown norway (bn) rats suffering from graft-versus-host disease (gvhd) subsequent to an allogeneic injection of adult lewis (l) lymph node cells (experimental). one micron thick autoradiographs were compared between such experimental and control littermates having received the same number of syngeneic adult bn cells. both experimental and control animals received tritiated deoxythymidine (3hdt) one hour ... | 1976 | 12607 |
| lonetyle: development of tolerance and barbiturate-like physical dependence in animals. | | 1976 | 12640 |
| esterolysis of oxyprothepin decanoate in vitro proceedings. | | 1976 | 12641 |
| the protective action of certain anaesthetics and tranquilizers against the effects of hyperbaric oxygen. | the protective effects of pentobarbitone, hydroxydione and diazepam against acute and chronic toxicity of high-pressure oxygen (hpo) were studied in rats. during exposure to hyperbaric oxygen body temperature was measured and ecg as well as emg tracings from the diaphragm were obtained. long term observations of animals after the exposure to hpo were conducted. pentobarbitone and hydroxydione reduced the manifestations of acute toxicity but increased those of chronic toxicity. diazepam reduced t ... | 1976 | 12648 |
| effect of ph on ammonia production by renal mitochondria. | nh3 production by renal cortical mitochondria was studied under conditions of metabolic acidosis induced in vivo and with ph manipulations of the media bathing mitochondria from normal rats. a hco3- medium equilibrated with o2 and co2 was utilized with glutamine concentrations of either 10 or 0.5 mm. with chronic acidosis nh3 production increased significantly at either substrate concentration. similar results were obtained with rotenone in the media, both with chronic acidosis and with acidosis ... | 1976 | 12662 |
| growth of aureobasidium pullulans on straw hydrolysate. | growth characteristics and cell properties of aureobasidium (pullularia) pullulans were studied. the organism grew well on an acid hydrolysate of ryegrass straw over a wide range of ph and temperature. the optimum temperature and ph for the growth of the organism were 32 degrees c and 5.5, respectively. a cell yield of 1.5 g/liter of straw hydrolysate was obtained. the dried cell mass contained 42.6% crude protein, 0.4% crude fat, and 6.4% nucleic acids. the essential amino acid profile of the m ... | 1976 | 12721 |
| nicotinic acid and alcoholism proceedings. | | 1976 | 12737 |
| identity of isoenzyme 1 of histidine-pyruvate aminotransferase with serine-pyruvate aminotransferase. | after glucagon injection, rats showed virtually identical percentage increases in hepatic histidine-pyruvate aminotransferase and serine-pyruvate aminotransferase activities, both in the mitochondria and in the cytosol. histidine-pyruvate aminotransferase isoenzyme 1, with pi8.0, was purified to homogeneity from the mitochondrial fraction of liver from glucagon-injected rats. the purified enzyme catalysed transamination between a number of amino acids and pyruvate or phenylpyruvate. for transami ... | 1976 | 12742 |
| the role of glucocorticoids in the regulation of the diurnal rhythm of hepatic beta-hydroxy-beta-methylglutaryl-coenzyme a reductase and cholesterol 7 alpha-hydroxylase. | the microsomal activities of the hepatic enzymes hydroxymethylglutaryl-coa reductase and cholesterol 7 alpha-hydroxylase exhibit a diurnal rhythm with maximum activities observed during the dark period and minimum activities around noon (12:00h). this diurnal rhythm was maintained for both enzymes after adrenalectomy, but the amplitude of variation for the activity of both enzymes was greatly decreased. a single injection of cortisol administered to adrenalectomized rats 3h before the expected m ... | 1976 | 12745 |
| mechanism of inhibition by carbonyl cyanide m-chlorophenylhydrazone and sodium deoxycholate of cytochrome p-450-catalysed hepatic microsomal drug metabolism. | 1. treatment of liver microsomal fraction with 0.03-0.12% sodium deoxycholate and 0.005-0.06 mm carbonyl cyanide m-chlorophenylhydrazone decreases phospholipid-dependent hydrophobicity of the microsomal membrane, assayed by the kinetics of 8-anilinonaphthalene-1-sulphonate binding and ethyl isocyanide difference spectra. 2. sodium deoxycholate at a concentration of 0.01% lacks its detergent properties, but competitively inhibits aminopyrine binding and activates the initial rate of nadph-cytochr ... | 1976 | 12746 |
| phosphatidylinositol kinase and diphosphoinositide kinase of rat kidney cortex: properties and subcellular localization. | the properties of phosphatidylinositol kinase and diphosphoinositide kinase from rat kidney cortex were studied. the enzymes were completely mg2+-dependent. cutscum detergent activated phosphatidylinositol kinase, but diphosphoinositide kinase was inhibited by all detergents tested. the ph optima were 7.7 for phosphatidylinositol kinase and 6.5 for diphosphoinositide kinase. on subcellular fractionation of kidney-cortex homogenates by differential centriflgation, the distribution of phosphatidyl ... | 1976 | 12747 |
| effect of phenylalanine metabolites on the activities of enzymes of ketone-body utilization in brain of suckling rats. | 1. the effects of phenylalanine and its metabolites (phenylacetate, phenethylamine, phenyl-lactate, o-hydroxyphenylacetate and phenylpyruvate) on the activity of 3-hydroxybutyrate dehydrogenase (ec 1.1.1.30) 3-oxo acid coa-transferase (ec 2.8.3.5) and acetoacetyl-coa thiolase (ec 2.3.1.9) in brain of suckling rats were investigated. 2. the 3-hydroxybutyrate dehydrogenase from the brain of suckling rats had a km for 3-hydroxybutyrate of 1.2 mm. phenylpyruvate, phenylacetate and o-hydroxyphenylace ... | 1976 | 12750 |
| oxygen toxicity in the perfused rat liver and lung under hyperbaric conditions. | 1. in the lung and liver of tocopherol-deficient rats, the activities of glutathione peroxidase and glucose 6-phosphate dehydrogenase were increased substantially, suggesting an important role for both enzymes in protecting the organ against the deleterious effects of lipid peroxides. 2. facilitation of the glutathione peroxidase reaction by infusing t-butyl hydroperoxide caused the oxidation of nicotinamide nucleotides and glutathione, resulting in a concomitant increase in the rate of release ... | 1976 | 12754 |
| acute effects in vivo of anti-insulin serum on rates of fatty acid synthesis and activities of acetyl-coenzyme a carboxylase and pyruvate dehydrogenase in liver and epididymal adipose tissue of fed rats. | plasma insulin concentrations in fed rats were altered acutely by administration of glucose or anti-insulin serum. rates of fatty acid synthesis in adipose tissue and liver were estimated from the incorporation of 3h from 3h2o. in the adipose tissue dehydrogenase and acetyl-coa carboxylase were evident. in liver, although changes in rates of fatty acid synthesis were found, the initial activity of pyruvate dehydrogenase did not alter, but small parallel changes in acetyl-coa carboxylase activity ... | 1976 | 12755 |
| aldehyde reductase from rat liver is a 3 alpha-hydroxysteroid dehydrogenase. | | 1976 | 12759 |
| cyclic amp-dependent amino acid uptake in intestine--the importance of beta-adrenergic agonists. | | 1976 | 12760 |
| characterization of rat skeletal muscle monoamine oxidase. | | 1977 | 12761 |
| effect of cyproterone acetate on the proteinase activities of adult rat testis and epididymis. | the in vivo and in vitro effects of cyproterone acetate (ca), an antiandrogenic compound, on the proteinase activities in epididymal and testicular spermatozoa in male albino rats was studied. ca was injected intramuscularly at a dose of 50 mg/kg daily for 10, 20, and 30 days. the testis and epididymis were homogenized and submitted for enzyme assay. the in vitro experments involved the incubation of supernatents from centrifuged testis and epididymis for 30 minutes with ca. proteinases were a ... | 1977 | 12762 |
| piroxicam, a novel anti-inflammatory agent. | piroxicam (cp-16 171) is a potent acidic anti-inflammatory agent structurally distinct from the current agents such as indometacin, phenylbutazone or naproxen. pharmacokinetic studies indicate a longer plasma half-ife for piroxicam than for these agents. potency in the range of indometacin is observed when piroxicam is tested in the carrageenan rat paw edema model. this activity is not dependent on an intact adrenocorticoid system. the high potency, long half-life and absence of cardiovascular o ... | 1976 | 12765 |
| profile of pharmacological actions of nab 365 (clenbuterol), a novel broncholytic agent with selective activity on adrenergic beta2-receptors (author's transl). | effects of 4-amino-alpha-(tert.-butylamino)methyl-3,5-dichlorobenzyl alcohol hydrochloride (clenbuterol, nab 365) on the adrenergic beta-receptors were investigated and compared with those of isoproterenol and salbutamol. the beta2-mimetic activity of clenbuterol on the smooth muscle of bronchi, uterus and vessels after i.v. injection corresponds to that of salbutamol in all laboratory animals. when given subcutaneously or as an aerosol clenbuterol is even somewhat more effective than isoprotere ... | 1976 | 12768 |
| synthetic analgesics: n-(1-2-arylethyl-4-substituted 4-piperidinyl) n-arylalkanamides. | the synthesis of several 4-arylamino-4-piperdinecarboxylic acids is reported. these acids were starting materials for the preparation of alpha-amino esthers, ethers and ketones. different synthetic approaches are described. suitable substitution on both nitrogen atoms afforded extremely potent analgesics. thus, methyl 4-n-(1-oxopropyl)-n-phenylamino-1-(2-phenylethyl)-4-piperidinecarboxylate (22),n-(4-(methoxymethyl)-2-2-(2-thienyl)ethyl-4-piperidinyl)-n-phenylpropranamide (67) and n-4-acetyl-1-( ... | 1976 | 12769 |
| n-4-substituted 1-(2-arylethyl)-4-piperidinyl-n-phenylpropanamides, a novel series of extremely potent analgesics with unusually high safety margin. | the intravenous analgesic activity and toxicity of a novel series of n-4-substituted 1-(2-arylethyl)-4-piperidinyl-n-phenylpropanamides was studied in rats. onset, potency and duration of analgesic action were assessed in the tail withdrawal test and compared with the activity of fentanyl, (+)-cis-3-methylfentanyl (r 26 800), morphine, and pethidine. all compounds studied were found to be extremely potent analgesics characterized by an unusually high safety margin. methyl 4-n-(1-oxopropyl)-n-phe ... | 1976 | 12771 |
| sufentanil, a very potent and extremely safe intravenous morphine-like compound in mice, rats and dogs. | sufentanil (r 30 730), n-4-methoxymethyl)-1-2-(2-thienyl)ethyl-4-piperidinyl-n-phenylpropanamide, is a chemically novel, highly potent and extremely safe intravenous morphine-like agent in laboratory animals. in mice r 30 730 i.v. is 2304 times more potent than morphine (hot plate ed50's: 0.0028 and 6.45 mg/kg, respectively). the i.v. safety margin of r 30 730 in mice is 1 : 6 679 (ld50 = 18.7 mg/kg). under the same experimental conditions the safety margin of pethidine is 1 : 7.97, of morphine ... | 1976 | 12772 |
| failure of benzoctamine to influence the activity of rat striatum tyrosine-hydroxylase. | the influence of benzoctamine (tacitin) on rat striatum tyrosine-hydroxylase was analized. injection of 100 mg benzoctamine/kg body weight caused no alteration in the tyrosine-hydroxylase activity whilst a decrease of about 60% in the activity was recorded after treatment with a-methyl-p-tyrosine a known inhibitor of tyrosine-hydroxylase. the present results differ from those of maitre et al. which indicated that benzoctamine inhibited tyrosine-hydroxylase activity. | 1976 | 12774 |
| oxidation of spermidine and spermine in rat liver: purification and properties of polyamine oxidase. | a novel enzyme responsible for the oxidation of spermidine and spermine has been found in rat liver. spermidine is shown to be degraded to putrescine and 3-aminopropionaldehyde, and spermine to be cleaved to spermidine and 3-aminopropionaldehyde. a single enzyme catalyzing both reactions and designated as polyamine oxidase has been purified 4000-fold to electrophoretic homogeneity. polyamine oxidase appears to be a flavoprotein, containing flavin adenine dinucleotide (fad) as a prosthetic group. ... | 1977 | 12798 |
| hydrolysis of chyle cholesterol esters with cell-free preparations of rat liver. | 1. the effect of ph on the hydrolysis of chylomicron and chylomicron remnant cholesterol ester with rat liver homogenate was examined. the hydrolysis had three ph optima, at ph 4.5, at ph 6.0-6.5 and at ph 8.5. at the two upper ph optima extensive cholesterol ester hydrolysis occurred without simultaneous degradation of the triacylglycerol portion. 2. similarly, microsomes (at ph 6.5-8.0) and 100 000 x g supernatant (at ph 7.5-8.5) efficiently hydrolyzed the cholesterol ester but not the triacyl ... | 1976 | 12799 |
| effect of sodium fluoride on glucose-6-phosphate dehydrogenase activity in the rat uterus. | intrauterine administration of 50 mumol of naf to the ovariectomized mature rat causes a 2--3-fold increase in the total uterine glucose-6-phosphate dehydrogenase activity within 24 h. the response is characterized by a 4--6 h lag with a maximum effect from 24 to 36 h after a single treatment. uterine glucose-6-phosphate dehydrogenase activity continues to increase with daily administration of naf through 4 days. the naf-induced response is blocked by prior intrauterine administration of cyclohe ... | 1976 | 12802 |
| acid inactivation of short-lived rat liver enzymes. | the stabilities of nine rat liver cytosol enzymes were compared at a variety of ph values. the cytosol enzymes studied were (a) those with half-lives in vivo of 3 days or longer: lactate dehydrogenase, arginase, glyceraldehyde phosphate dehydrogenase and alanine aminotransferase, (b) those with half-lives in vivo shorter than 2 days; glucokinase, dihydroorotase, serine dehydratase and tyrosine aminotransferase and (c) catalase, which has an intermediate half-life of 2.5 days for the protein prot ... | 1976 | 12803 |
| proton electrochemical potential in steady state rat liver mitochondria. | delta approximately muh has been determined in steady state mitochondria by measuring the magnitude of delta ph on the distribution of acetate and of deltapsi on the distribution of k+, tetraphenylphosphonium, ca2+, sr2+ and mn2+. (1) the matrix concentration of divalent cations has been calculated from the total cation uptake, from the increase of matrix volume and from the esr sextet signal of mn(h2o)l2+. the cat2+i based on osmotic data is about five times higher than that based on esr measur ... | 1977 | 12814 |
| partial purification and properties of a cyclic 3',5'-amp-independent protein kinase from rat liver. | 1. a cyclic 3',5'-amp-independent protein kinase (atp : protein phosphotransferase, ec 2.7.1.37) from rat liver cytosol was partially purified and characterized. purification by (nh4)2so4 precipitation, deae-cellulose, bio gel a-0.5 m and cellulose phosphate chromatography increased the specific activity about 700-fold. 2. an endogenous protein substrate was closely associated with the protein kinase and was not separable from this enzyme up to the cellulose phosphate stage. after phosphorylatio ... | 1977 | 12821 |
| rat intestinal phosphodiesterase ii. properties of the highly purified enzyme and its inactivation by iodoacetic acid. | a highly purifed preparation of rat intestinal phosphodiesterase ii (oligonucleate 3'-nucleotidohydrolase, ec 3.1.4.18) has been studied using a synthetic substrate, thymidine 3'(2,4-dinitrophenyl) phosphate. the enzyme was most active between ph 6.1 and ph 6.7 and was inhibited by cu2+ and zn2+ but unaffected by edta, mg2+, co2+, and ni2+. the reaction rate decreased at high levels of enzyme because of competitive inhibition by deoxythymidine 3'-phosphate, a reaction product, which showed a ki ... | 1977 | 12824 |
| studies on the metabolism of beta-carotene and apo-beta-carotenoids in rats and chickens. | (1)the relative abilities of the various fractions of rat and chicken liver to oxidize and reduce retinal and 8'-and 12'-apo-beta-carotenal were investigatjed and it has been shown that, while retinal is exclusely oxidized by the soluble fraction, the apocarotenals are mostly oxidized by the particulate fractions of the homogenate. (2) addition of nad+ or nadp+ markedly activated the oxidation of the apocarotenals, but not of retinal by the particulate fractions. (3) considerable amounts of reti ... | 1976 | 12834 |
| very low density lipoprotein. dissociation of apolipoprotein c during lipoprotein lipase induced lipolysis. | the fate of apo c in rat plasma very low density lipoprotein (vldl) during lipolysis was studied using vldl labeled specifically with 125i-labeled apo c and purified bovine milk lipoprotein lipase. incubations were carried out in vitro and included serum-containing systems and albumin containing systems. free fatty acids generation proceeded with time of incubation in the two systems. it, however, was enhanced 1.5--2 fold by the presence of serum. 125i-labeled apo c equilibrated between very low ... | 1976 | 12835 |
| inhibition of in vitro cholesterol synthesis by fatty acids. | inhibitory effect of 44 species of fatty acids on cholesterol synthesis has been examined with a rat liver enzyme system. in the case of saturated fatty acids, the inhibitory activity increased with chain length to a maximum at 11 to 14 carbons, after which activity decreased rapidly. the inhibition increased with the degree of unsaturation of fatty acids. introduction of a hydroxy group at the alpha-position of fatty acids abolished the inhibition, while the inhibition was enhanced by the prese ... | 1976 | 12837 |
| cimetidine and ulcers. | | 1976 | 12853 |
| catecholamine turnover alterations in discrete areas of the median eminence of the 4- and 5-day cyclic rat. | using quantitative microfluorimetry in combination with tyrosine hydroxylase inhibition (h44/68) the concentration and turnover of noradrenaline (na) and dopamine (da) was studied in the subependymal layer (sel) and the medial (mpz) and lateral palisade zone (lpz) of the rat median eminence during the 4- and 5- day vaginal estrous cycle. significant cyclic variations were only found in sel and lpz. the na turnover in sel was high on proestrous and low on all other days of the 4-day estrous cycle ... | 1977 | 12857 |
| responses of neurons in the suprachiasmatic nuclei of the hypothalamus to putative transmitters. | | 1977 | 12858 |
| effect of 17 beta-estradiol on hypothalamic tyrosine hydroxylase activity. | | 1977 | 12859 |
| effects of kainate and other glutamate analogues on cyclic nucleotide accumulation in slices of rat cerebellum. | | 1977 | 12861 |
| cerebral carbohydrate metabolism during acute carbon monoxide intoxication. | the cerebral metabolic effects of 2.5, 5, 7.5, 10, 20, 30 and 60 min exposure to 1% co were studied in lightly anesthetized rats by measurement of cerebral cortical contents of selected glycolytic and citric acid cylce intermediates, as well as tissue energy phosphates. the initial change in the glycolytic sequence occurred at 2.5 min with decreases in tissue glucose and glucose-6-phosphate and increases in fructose-1-6-diphosphate which indicated an activation of phosphofructokinase and hexokin ... | 1977 | 12862 |
| dissociation of 5-fluorouracil uptake from intracellular ph in walker 256 carcinosarcoma. | the influence of intracellular ph (phi) upon 5-fluorouracil (5-fu) uptake has been studied in slices of walker 256 carcinosarcoma and rat liver. alteration of phi was achieved by the addition of either glucose alone or together with oxamic acid to the incubation medium. results indicated that 5-fu uptake by the tumor slices was not dependent upon phi, but was enhanced by the presence of glucose. uptake of 5-fu by liver slices appeared to follow a pattern predictable from the phi and the pk of th ... | 1976 | 12865 |
| the effect of fixation conditions on the ultrastructural appearance of gastrin cell granules in the rat gastric pyloric antrum. | the ultrastructural appearance of gastrin cell (g cell) granules was studied after different fixation procedures. when the ph of prefixation was varied there was greater preservation of the electron density of granule cores after acidic (ph 5.0 and 6.0) than after neutral or alkaline (ph 7.0 and 8.0) prefixation. increasing duration of prefixation at ph 7.3 resulted in progressive loss of electron density of the granule core with swelling and occasional rupture of the limiting membrane. in tissu ... | 1977 | 12869 |
| effect of partial hepatectomy on the graft versus host reaction after intrahepatic lymphoid tissue implantation. | | 1977 | 12872 |
| hydrochloric acid secretion of fetal rat gastric mucosa. | in rat, spontaneous secretion of hydrochloric acid by gastric mucosa takes place before birth. from day 20 of gestation until birth, the ph of gastric content markedly decreases, reaching 3 ph-units in newborns. during this period, cl- concentration in gastric juice increases, while p-co2 remains constant. | 1976 | 12878 |
| total lactate dehydrogenase and its isoenzymes in serum in the presence of penicillamine and other sulfhydryl compounds. | toward delineation of changes in total lactate dehydrogenase (ldh) and in the distribution of ldh isoenzymes as assessed by polyacrylamide disc electrophoresis, we inbucated human and rat sera with various agents, notably sulfhydryl compounds. although artefacts were apparent when these agents were used without preliminary adjustment of ph, we saw little alteration in total unitage when one or two volumes of serum was mixed with one volume of any of several thiols, especially penicillamine, at a ... | 1977 | 12885 |
| stimulation of growth hormone release by luteinizing hormone-releasing hormone and melanocyte-stimulating hormone-release inhibiting hormone in the hypophysectomized rat bearing an ectopic pituitary. | intrajugular administration of lhrh (0-6 and 1-2 mug) in hypophysectomized rats which received renal grafts of anterior pituitary induced a small but significant rise in plasma gh 5 and 10 min post-treatment. lhrh, at the same dose levels, was ineffective in weight-matched intact controls. mif, at the dose of 1-2 mug, induced a slight gh rise 5 min after treatment in hypophysectomized trasnplanted rats, while it was ineffective in intact controls. unlike the two hypothalamic peptides, alpha-msh ... | 1976 | 12896 |
| the immune response in cirrhotic rats. antigen distribution, humoral immunity, cell-mediated immunity and splenic suppressor cell activity. | the immunological disturbances occurring as a result of liver disease have been studied in an animal model of cirrhosis. the mononuclear phagocytic cells of the normal liver phagocytose large amounts of antigen irrespective of whether that antigen is injected directly into the portal or into the systemic circulations. the liver therefore acts as a filter 'in series' and 'in parallel' with the spleen and reduces the immunogenicity of antigens entering the organism by either of these routes. in ra ... | 1976 | 12899 |
| blood kinetics and accumulation in man of a new benzodiazepine agent (pinazepam) after oral administration. | | 1976 | 12906 |
| choice of sex before conception?. | | 1975 | 12912 |
| neonatal treatment with sex steroids: relationship between the uterotropic response and the estrogen "receptor" in prepubertal rats. | we tested the hypothesis that neonatal treatment of rats with testosterone propionate (tp) or estradiol benzoate (eb) reduces the uterine responsiveness to estradiol and reduces the concentration of estrogen "receptor" before puberty, and that both of these events precede the onset of the persistent estrus syndrome. thre-day-old female rats were injected with 100 mug eb, tp or sesame oil (controls) and at 23 and 31 days of age (before the onset of puberty) the uterine cytoplasmic content of spec ... | 1977 | 12934 |
| lack of glucose effect on the induction of 5-aminolevulinate synthetase and tyrosine aminotransferase in the isolated perfused rat liver. | in the isolated perfused rat liver, both 5-aminolevulinate synthetase and tyrosine aminotransferase were induced by the addition of 3.5 mmol/l allylisopropylacetamide and 58 mumol/l dexamethasone to the perfusion medium. glucose (40 mmol/l) did not affect either the induction of these enzymes or the intrahepatic level of cyclic amp. the results suggest that the glucose effect on the induction of 5-aminolevulinate synthetase and tyrosine aminotransferase in vivo is mediated by extrahepatic factor ... | 1976 | 12936 |
| mitochondrial isocitrate dehydrogenase and isocitrate oxidation of rat ventral prostate. | mitochondrial preparations isolated from rat ventral prostate were capable of oxidizing isocitrate by way of nadp isocitrate dehydrogenase (nadp-idh) and nad-idh. nad-idh activity required adp for activation. the ph responses for nad-idh and nadp-idh were quite different. the results indicated that two different enzymes were involved in the nad- and nadp-idh activities. indirect evidence indicated that nadph-nad transhydrogenase activity might also be involved in the mitochondrial pathway for is ... | 1976 | 12937 |
| translation of mrna from rat-liver polysomes into tyrosine aminotransferase and tryptophan oxygenase in a protein-synthesizing system from wheat germ. effects of cortisol on the translatable levels of mrna for these two enzymes. | messenger rna was isolated from rat liver polysomes by phenol/chloroform extraction and subsequent oligo(dt)-cellulose chromatography. the mrna was translated in a protein-synthesizing system in vitro derived from wheat germ. the system was optimized in respect to mg2+ and k+. the presence of spermidine or spermine is necessary for the synthesis of polypeptides having molecular weights of over 20 000. in the absence of the bases only small molecular weight products are formed. the amount of prot ... | 1976 | 12944 |
| effect of thyroid hormones on microsomal fatty acid chain elongation synthesis in rat liver. | evidence is presented that rat liver microsomal fatty acid chain elongation synthesis and desaturation, as well as acetyl-coa carboxylase and fatty acid synthetase, are strongly influenced by thyroid hormone level. conversely, the fatty acid chain elongation system in mitochondria, unlike the oxidative capacity of palmitate, nadh, succinate and malate, does not seem significantly affected by the thyrotoxic state. in triiodothyronine-induced or thyroxine-induced hyperthyroidism, rat liver acetyl- ... | 1976 | 12955 |
| esterolytic activities of rat intestinal mucosa. 1. characterization, cellular distribution and subcellular localization of a glycerol-ester hydrolase. | the preferential cellular distribution in the villus tip and the subcellular localization in the endoplasmic reticulum of an intestinal glycerol-ester hydrolase from rat mucosa are described. the enzyme is shown not to be from either pancreatic or bacterial origin; it catalyzes the hydrolysis of short- and medium chain triglycerides and of p-nitrophenylacetate. contrarily to the specificity found for the pig intestinal lipase (serrero, négrel and ailhaud, 1975), no activity is detectable against ... | 1976 | 12956 |
| esterolytic activities of rat intestinal mucosa. 2. purification and properties of a glycerol-ester hydrolase. | a glycerol-ester hydrolase from rat intestinal cells has been purified using chromatography on carboxyhexanoyl-sepharose-glyceryldioctanoate and preparative gel electrophoresis. the enzyme gives a single band by analytical gel electrophoresis; it is a monomer of molecular weight 68000. the optimum ph for its action on glyceryl tributyrate is between 8.0 and 8.5; the activation energy was calculated to be 8.7 kcal x mol-1 (36.4 kj/mol). its substrate specificity is mainly directed against esters ... | 1976 | 12957 |
| the effect of endogenous phosphate on the h+/mn2+ ratio and the state of mn2+ in the mitochondrial matrix. | 1. kinetics and stoichiometry of h+ extrusion and reuptake and of mn2+ uptake and release have been measured in respiring liver mitochondria in the absence of external added pi. h+ and mn2+ fluxes are parallel during aerobic cation uptake but not during uncoupler induced cation release. the h+/mn2+ is 1.24. addition of sh reagents, in concentrations inhibiting the pi carrier, modifies the kinetics of h+ extrusion and of mn2+ uptake and release. the slow phase of uncoupler induced mn2+ release is ... | 1976 | 12961 |
| on the optical activity of ionized tyrosyl residues in ovine lutropin. | the effect of alkali on the circular dichroic (cd) spectra of ovine lutropin and its subunits has been studied. mild alkaline ph induces the appearance of a new optically active band in the 250-nm region of the spectra of lutropin without any detectable alteration in the secondary structure of the protein. this change is reversible and can be correlated with ionization of 2--3 exposed tyrosyl residues in the intact hormone. in a previous report from this laboratory it was concluded that the thre ... | 1977 | 12975 |
| acute hypotensive effect of combined beta1-adrenoceptor blockade and beta2-adrenoceptor stimulation in spontaneously hypertensive rats (shr). | the effect on heart rate (hr) and blood pressure (bp) of metoprolol, propranolol and terbutaline, applied alone or in combinations was studied in spontaneously hypertensive rats. terbutaline had little effect on bp and hr. propranolol combined with terbutaline had no effect while metoprolol combined with terbutaline decreased bp by 48 mm hg without affecting hr. thus the beta2-mediated increase in peripheral vascular resistance after terbutaline was revealed by a drop in bp after beta1-blockade ... | 1977 | 12983 |
| comparison of adiphenine and trh effects on tsh release by rat pituitary in vitro. | the mechanism of action of adiphenine on in vitro rat anterior pituitary tsh release was compared to that of the physiological stimulator trh. the comparative study showed that adiphenine and trh were able to increase tsh release in a dose-dependent manner, had similar time courses of action for equipotent stimulating concentrations and produced similar aspects of stimulated tsh cells. however, there were several differences between the effects of adiphenine and trh. adiphenine action was inhibi ... | 1977 | 12985 |
| perlapine and dopamine metabolism: prediction of antipsychotic efficacy. | a model for the prediction of antipsychotic efficacy based on the dose-dependent increase in levels of 3,4-dihydroxyphenylacetic acid (dopac) in the striatum and tuberculum olfactorium of the rat is presented. the effect of perlapine, a sleep-promoting and sedative agent reported to lack antipsychotic efficacy, was compared in this system to haloperidol, chlorpromazine and clozapine. all four drugs produced a dose-dependent increase in dopac in the two dopamine-rich structures. the potency of pe ... | 1977 | 12986 |
| neurotensin receptor binding, regional and subcellular distributions favor transmitter role. | | 1977 | 12987 |
| pharmacology of a new phthalane (lu 10-171), with specific 5-ht uptake inhibiting properties. | the pharmacological profile of a new bicyclic substance, lu 10-171 (1-(3-(dimethylamino)propyl)-1-(p-fluorophenyl)-5-phthalancarbonitril), is described and compared with that of existing tricyclic thymoleptics. in mice and rats the compound exhibited marked 5-ht potentiating properties both in vivo and in vitro, being 5-10 times as active as chlorimipramine. the tests included 5-ht-, 5-htp- and tryptophan-potentiation. in monoamine oxidase inhibitor treated dogs and rabbits the compound caused a ... | 1977 | 12988 |
| effects of cimetidine and atropine sulfate on gastric secretion and healing of gastric and duodenal ulcers in rats. | cimetidine, a new histamine h2-receptor antagonist (50 or 100 mg/kg) and atropine sulfate (15 mg/kg) given intraduodenally, markedly inhibited gastric secretion in pylorus-ligated rats. cimetidine (100 or 200 mg/kg/day) given for 10 or 12 consecutive days orally in two divided doses, significantly promoted the healing rate of both gastric and duodenal ulcers induced in rats. atropine (30 mg/kg/day) also significantly accelerated the healing of duodenal ulcers but failed to affect gastric ulcers. | 1977 | 12989 |
| evidence in favour of the existence of a dopamine-free prolactin-inhibiting factor (pif) in rat hypothalamic extracts. | | 1977 | 12991 |
| apparent arylsulfatase a activity in excretory fluids. | | 1977 | 12994 |
| c-terminal fragment (residues 61-91) of beta-lipotropin: is it the natural opiate-like neurohormon of the brain? | | 1977 | 12995 |
| pressor action of propranolol; with special reference to relationship between the pressor action and peripheral vascular tone. | we showed in previous studies that pro pranolol produced a pressor action in the rat, and that this action was also observed in the spinal rat infused with adrenaline, noradrenaline and a mixture of isoproterenol and vasopressin, but not with vasopression alone. the action was also observed in the guinea pig infused with adrenergic beta-stimulants. in the present work, conditions in the peripheral vessels in which propranolol observed in the spinal rat infused with a mixture of various doses of ... | 1976 | 13028 |
| studies on regulation of fatty acid synthesis by thyroid hormone. | | 1976 | 13034 |
| stability of mammalian lens phosphofructokinase. | two interconvertible phosphofructokinase (pfk) forms were found in rat and human lenses; whereas only one predominant form was found in calf lens. pfk isolated from these lenses possessed a common property, i.e., ph-dependent cold (or acid) lability. the inactivation was prevented by including either adenosine triphosphate (atp) or fructose-6-phosphate (fru-6-p) in the incubating media. the protective effect of atp or fru-6-p was complete in rat or calf lenses. in human lens, although fru-6-p wa ... | 1977 | 13048 |
| adenosine triphosphate catabolism in homogenates of rat secretory enamel organs incubated in histochemical lead media. | to investigate how lead, when used as trapping agent, influences the atp hydrolysis and to study how atp is catalyzed in histochemical systems, homogenized secretory enamel organs were incubated in histochemical 3h-atp media. aliquots from the media were taken after 3, 10, 20 and 30 min, the atp and formed metabolites were separated by electrophoresis and radiometrically quantitated. in media lacking both lead and homogenate 2% of the atp was spontaneously hydrolyzed during 30 min incubation at ... | 1977 | 13054 |
| studies on cathepsins of rat liver lysosomes. iii. hydrolysis of peptides, and inactivation of angiotensin and bradykinin by cathepsin a. | systematic analysis of the hydrolysis of benzyloxycarbonyl (cbz)-dipeptides by cathepsin a ec 3.4.12.1 purified from rat liver lysosomes showed that multiple forms of cathepsin a preferentially cleave peptide bonds with leucine, methionine, and phenylalanine. cbz-met-met, -met-phe, -phe-met, and -phe-ala were hydrolyzed 6 to 8 times faster than the standard substrates, cbz-glu-phe and cbz-glu-tyr. the ph optima of the hydrolyses were 4.6 to 5.8. hydrolysis of peptide bonds with glycine, isoleuci ... | 1976 | 13061 |
| nadph-cytochrome p-450 reductase. circular dichroism and physical studies. | nadph-cytochrome p-450 reductase was purified from hepatic microsomes of phenobarbital and hydrocortisone-treated rats by detergent solubilization and column chromatography. this membrane protein contains 31 mol per cent hydrophobic amino acid residues, 6 half-cystine residues, and a single tryptophan residue as determined by amino acid analysis after mineral or organic acid hydrolysis. the free mobility of cytochrome p-450 reductase in sodium dodecyl sulfate was identical to that of several sol ... | 1977 | 13069 |
| activation of guanylate cyclase in cerebral cortex of rat by hydroxylamine. | hydroxylamine actived guanylate cyclase in particulate fraction of cerebral cortex of rat. activation was most remarkable in crude mitochondrial fraction. when the crude mitochondrial fraction was subjected to osmotic shock and fractionated, guanylate cyclase activity recovered in the subfractions as assayed with hydroxylamine was only one-third of the starting material. recombination of the soluble and the particulate fractions, however, restored guanylate cyclase activity to the same level as ... | 1977 | 13073 |
| assay and partial characterization of the solubilized cell surface receptor for immunoglobulin e. | the cell surface component (receptor) which specifically binds immunoglobulin e (ige) presumably forms an integral part of the functional chain involved in the antigen-induced ige-mediated degranulation of histamine-containing mast cells and basophils. this paper describes a simple (nh4)2so4 predipitation assay with which the interaction of ige with detergent-solubilized receptors can be reproducibly quantitated. receptor saturation was demonstrated and a linear response to receptor concentratio ... | 1977 | 13075 |
| the purification and characterization of rat liver lysosomal alpha-l-fucosidase. | the alpha-l-fucosidase from rat liver lysosomes was purified approximately 27,000-fold (from cytoplasmic extract) by a rapid procedure requiring only 7 h anf providing enzyme in a 20 per cent yield. the procedure is based upon affinity chromatography with agarose-epsilon-aminocaproyl-fucosamine. the isolated enzyme was found to be pure by a number of different analytical gel techniques and is essentially free of other lysosomal gylcosidases. the purified enzyme exhibits a positive periodic acid- ... | 1977 | 13077 |
| a novel mechanism for group translocation: substrate-product reutilization by gamma-glutamyl transpeptidase in peptide and amino acid transport. | gamma-glutamyl transpeptidase (gamma-gtp) is suggested to act as a carrier in the group translocation of oligopeptides and possibly some amino acids across cellular membranes. it is proposed that the process may involve the repetitive transfer of gamma-glutamyl groups to acceptor peptides which are being translocated from the exterior of the cell to its interior. after group translocation of the peptides has occurred with concomitant formation of gamma-glutamyl peptide products, it is suggested ... | 1976 | 13082 |
| effect of sulfonylureas on triglyceride metabolism in the rat liver: possible role of the lysosomes in hepatic lipolysis. | it has been suggested previously that chlorpropamide and other hypoglycemic sulfonylureas interfere with hepatic triglyceride breakdown. since ketogenesis from endogenous hepatic lipid stores is a measure of hepatic triglyceride hydrolysis, ketogenesis derived from endogenous lipids as well as ketogenesis derived from exogenously added isotopic oleate was determined in isolated hepatocytes from fasted rats in an attempt to identify the nature of the direct effects of sulfonylureas on hepatic lip ... | 1977 | 13085 |
| ectopic beta-adrenergic receptor binding sites. possible molecular basis of aberrant catecholamine responsiveness of an adrenocortical tumor adenylate cyclase. | the molecular basis for the aberrant catecholamine responsiveness of the adenylate cyclase of adrenocortical carcinoma 494 was explored. the adenylate cyclase of this corticosteroid-producing, transplanted, adrenal cancer of the rat was stimulated not only by adrenocorticotropic hormone and fluoride, but also by the beta-adrenergic agonist, isoproterenol. the adenylate cyclase of normal adrenal tissue was unresponsive to isoproterenol. direct binding studies with the specific high affinity b-adr ... | 1977 | 13086 |
| in situ localization of galactosyltransferase in surface mucous cells of the rat stomach. | cryostate sections of the rat stomach fundus were incubated in the presence of uridine 5'-diphosphate-3h-galactose. the radioactivity in the surface mucous epithelial cells was shown by autoradiography to be specifically incorporated into a supranuclear area, the area where in these cells the glogi system is situated. the incorporation lasted only 5-6 min and was mn++ dependent. galactose was probably incorporated into a beta-glycosidic bond. | 1977 | 13122 |