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At least 37 records · Page 2Linked to original sources

PubMed1977

The in vivo toxicity of CS2 to liver microsomes: binding of labelled CS2 and changes of the microsomal enzyme activities.

The binding of 35S and 14C labelled CS2 to liver microsomes was studied in control and phenobarbitone pretreated rats 3 and 6 hrs after an intraperitoneal injection. The level of hepatic cytochrome P-450, the activities of epoxide hydratase and UDP-glucuronosyltransferase were analyzed in the same animals. The binding of the sulphur label was considerably higher than that of carbon 3 hrs after the injection, the difference being less evident at 6 hrs.T he measurable P-450 declined after the CS2 injection. It was approximately 40% in the phenobarbitone pretreated rats and 60% in control rats of the values of animals which were not treated with CS2. CS2 did not affect microsomal epoxide hydratase activity, while it increased the measurable activity of UDP-glucuronosyltransferase. The increase was evident 3 hrs after the injection of CS2 in the phenobarbitone pretreated rats. It could also be detected in the control animals 6 hrs after the injection. The present data suggest that the change in the measureble P-450 results from the binding of the metabolite(s) of CS2 to the cytochrome, and its subsequent degradation. The increase in measurable UDP-glycuronosyltransferase activity results probably from the activated perturbation of the structure of microsomal membrane by the metabolites of CS2 in vivo.

Animals↗

PubMed1979

Biochemical studies on the muscle microsomes of Ascaris lumbricoides var. suum. II. Purification and characterization of b-type cytochrome and NADH-ferricyanide reductase from Ascaris muscle microsomes.

A b-type cytochrome and NADH-ferricyanide (FC) reductase were solubilized from Ascaris muscle microsomes by detergents and purified by column chromatography. The purified b-type cytochrome displayed absorption bands at 560 (alpha-peak), 525 (beta-peak), and 424 nm (gamma-peak), with a marked shoulder at 555 nm in the reduced from, 415 nm (gamma-peak) in the oxidized form. This absorption spectrum was different from that of rat liver microsomal cytochrome b5. The molecular weight was estimated to be about 100,000 by SDS-polyacrylamide gel electrophoresis, and the absorption spectrum of alkaline pyridine ferrohemochrome suggested that the prosthetic group of this cytochrome is protoheme. The molecular weight of the purified NADH-FC reductase was estimated to be about 55,000 by SDS-polyacrylamide gel electrophoresis. The purified reductase required NADH as a specific electron donor. The reductase efficiently reduced some redox dyes with NADH, but the reduction of cytochrome c was much slower. The purified reductase, like the membrane-bound reductase, was not inhibited by thiol reagents.

Animals↗

PubMed1978

Role of phosphatidylcholine on microsomal chain elongation and the fate of stearoyl-CoA in rat liver microsomes.

The effect of phosphatidylcholine dispersion on the chain elongation of palmitoyl-CoA in rat liver microsomes has been investigated. Addition of phosphatidylcholine increased the formation of stearic acid and its incorporation into phosphatidylcholine. In the presence or absence of phosphatidylcholine, newly-formed stearic acid was preferentially incorporated into the C-1 position of phosphatidylcholine. The incorporation of newly formed stearic acid into microsomes was much higher than that into the added phosphatidylcholine dispersion.

Acyl Coenzyme A↗

PubMed1978

Dysregulation of protein synthesis in injured liver. A comparative study on microsomal and cytosole enzyme activities, microsomal lipoperoxidation and polysomal pattern in D-galactosamine and carbon tetrachloride-injured livers.

Despite the presence of a marked decrease in liver protein content 48 h after a single injection of D-galactosamine, increased activities of glucose-6-phosphate dehydrogenase, low-Km hexokinase and pyruvate kinase type M2 were observed in the injured liver. Microsomal aniline hydroxylase activity and cytochrome P-450 content in liver decreased significantly in 48 h of galactosamine treatment but not in the first 2 h in contrast with carbon tetrachloride (CCL4) intoxication. The extents of those changes were not so great as in CCl4-treated rats. The disaggreation of polyribosomes in liver was observed in 24 h of galactosamine treatment. However, the formation of microsomal lipoperoxidation did not increase in the entire course of acute liver injury by the amino sugar. These results taken together with our previous observations indicate that the dysregulation of protein synthesis is an essential biochemical event of hepatocyte injury induced by treatment of rats with galactosamine as well as CCl4.

Animals↗

PubMed1977