Effects of tetrachlorvinphos on hepatic microsomal enzymes in the rat.

Abstract

The inducement of the hepatic microsomal enzymes in male rats following oral administration of tetrachlorvinphas (TCVP) for 7 days with the dosage of 150 mg/kg and the mechanism of its inducing effect were studied. It was confirmed that TCVP could enhance significantly the activity of hepatic microsomal enzymes, such as aniline hydroxylase, P-nitroanisole O-demethylase and uridine diphosphoglucuronyltransferase (UDP-GAT). Besides, it could also increase contents of microsomal cytochrome P-450 and microsomal protein. In rats it shortened pentobarbital sleeping time. These results demonstrated that repeated administration of TCVP might induce the activity of hepatic microsomal enzymes in rats. The inducing effect of TCVP could be blocked by DL-ethionine, an inhibitor of aminoacids. Furthermore, TCVP failed to increase enzymic activity in vitro. These findings suggested that the inducing effect of TCVP on the activity of hepatic microsomal enzymes could be explained by accelerating synthesis of microsomal protein.