TY - JOUR T1 - Induction of hepatic gamma-glutamyl transpeptidase in rats by repeated administration of aminopyrine. JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 795 LP - 800 VL - 221 IS - 3 AU - T Satoh AU - T Igarashi AU - T Hirota AU - H Kitagawa Y1 - 1982/06/01 UR - http://jpet.aspetjournals.org/content/221/3/795.abstract N2 - The effect of a 20-day administration of aminopyrine (600 mg kg-1) as well as two metabolites of aminopyrine, 4-aminoantipyrine (525 mg kg-1) and 4-acetamidoantipyrine (635 mg kg-1), on several hepatic, kidney and serum enzyme activities were investigated. In the aminopyrine-treated group, a pronounced induction of gamma-glutamyl transpeptidase was shown in the whole homogenate as compared to that in the hepatic microsomes. Serum gamma-glutamyl transpeptidase activity was also increased by administration of aminopyrine or 4-aminoantipyrine. No change in gamma-glutamyl transpeptidase activity was observed in kidney and hepatic cytosolic fractions. In all cases, 4-acetamidoantipyrine treatment showed no significant change in the enzyme activities tested. Under the same experimental condition, the amounts of cytochrome P-450 and b5, the activities of aminopyrine N-demethylase, aniline hydroxylase and carboxylesterase of liver microsomes were all induced in the aminopyrine- and 4-aminoantipyrine-treated rats. The activities of NADPH cytochrome c reductase and NADH ferricyanide reductase were also increased. The results in this paper support the view that repeated administration of aminopyrine induces hepatic membrane-bound enzyme, particularly, gamma-glutamyl transpeptidase activity. ER -