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181. [Liver extract effect on liver microsomal system and on an experimental model of intoxication].
作者: A Benakis.;J Corthay.;P Medilanski.;Y Dormard.;J C Lévy.
来源: C R Seances Soc Biol Fil. 1977年171卷2期322-9页
A lyophilized liver extract (FLR) lengthens hexobarbital action in control rats ; it decreases slightly the induction of hepatic microsomal enzymes and normalizes diphenylhydantoin protection against electroshock seizure in phenobarbital-treated animals ; in the event of a CC14 intoxication, this extract reestablishes values close to normal for mebubarbital metabolism in mice and for BSP clearance in rats. FLR could act in regularizing drug metabolism.
182. [Characteristics of the induction of pulmonary and renal benzopyrene hydroxylase by cigarette smoke].183. [Hepatic-cell enzyme induction using phenobarbital: applications to the treatment of jaundice].184. [Regulation of aspartate-ammonia-lyase (aspartase) biosynthesis in Pseudomonas fluorescens].
Variations in aspartasic activity in various media are due to aspartate-ammonium lyase induction and to regulation of the biosynthesis of this enzyme. Evidence for neosynthesis of the enzyme is provided by labelling and separation of the protein. The inducer appears to be aspartic acid. The biosynthesis is subject to pronounced catabolic repression. The physiological function of aspartate-ammonium lyase is discussed.
185. [Cytochrome P450. Its importance in toxicology. II. Regulation of its biosynthesis and its activity. Activation and inhibition].
The authors emphasize the influence of hormonal and nutritional factors on the activity level of microsomal enzymes. Induction process of hepatic cytochrome P450 and microsomal enzymes by xenobiotics are described. The existence of different types of hemoprotein P450 in response to the action of different inductors is discussed. We also propose some hypothesis concerning the action mechanism of inhibitors of microsomal enzymes and we point out the role of environmental pollutants.
186. [The effect of pretreatment with enzyme inducers on the acute toxicity of DDT (1, 1-bis-(p-chlorophenyl)-2,2,2-trichloroethane) in rats].
A study was undertaken to investigate the influence of various hepatic enzyme inducers on the acute toxicity of the organohalogenated insecticide DDT. Adult female rats were pretreated with sodium phenobarbital (50 mg/kg/day during 5 days), 3-methylocholanthrene (20 mg/kg/day during 3 days), and norethandrolone (20 mg/kg/day during 14 days), and were then given 150 mk/kg of DDT per os. Phenobarbital was shown to lower the toxicity of DDT, norethandrolone had the opposite effect, and 3-methylcholanthrene was without any significant effect. After a phenobarbital pretreatment, the cerebral concentration of DDT was lowered, possibly as a result of an increased biotransformation of DDT to DDD in the liver. On the other hand, norethandrolone did not appear to modify the hepatic conversion of DDT to DDD, nor the cerebral concentration of DDT. Further studies are needed to explain the potentiating effect of norethandrolone on the acute toxicity of DDT.
189. [Action of vitamin A on the extent of enzyme induction].190. [Proceedings: Catabolic repression by nitrogen of arginase synthesis in Saccharomyces cerevisiae].191. [The inducibility of aspartate-ammonium lyase of Pseudomonas fluorescence (type R)].193. [Environmental effect on metabolism of exogenous molecules in liver microsomes].194. [Permissive effect of hydrocortisone on serine dehydratase induction by glucagon in rat liver; comparison with tyrosine aminotransferase].195. [Preparation and study of human plasmatic lysozyme].196. [Vitamin A and DDT].198. [Experimental biological toxicology of white phosphorus].200. [Influence of the hydrosoluble vitamin content of the diet and treatment by barbiturates on several effects of azoic dyes]. |