Effect of 1-m-tolueneazo-2-naphthol on hepatic drug metabolism. II. Induction of UDP-glucuronyltransferase.

Effect of potent cytochrome P-448 inducer, 1-m-tolueneazo-2-naphthol (m-TAN) on hepatic microsomal UDP-glucuronyl-transferase (UDPGT) activity was studied. The UDPGT activity reached the maximum level on the fifth day after either a single injection or consecutive daily administrations. The UDPGT activities towards p-nitrophenol, 1-naphthol and chloramphenicol were increased up to 6,2.5 and 1.8 folds of control levels respectively, in microsomes from m-TAN treated rats. 3-Methylcholanthrene, on the other hand, caused 4 and 2 fold increase in UDPGT activities towards p-nitrophenol and 1-naphthol, respectively, but did not cause significant increase in UDPGT activity towards chloramphenicol. It is concluded that m-TAN is a new potent inducer of UDPGT activity with its potency exceeding that of 3-methylcholanthrene and the pattern of induction, a little different from that of 3-methylcholanthrene.