title: Metabolism of benzo(a)pyrene by guinea pig pancreatic microsomes.
abstract: The in vitro microsomal metabolism of the strain 13 guinea pig pancreas was investigated by determining the benzo(a)pyrene (BP) hydroxylase activity in the 9000 x g supernatant and microsomal pellet. BP hydroxylase activity in both 9000 x g supernatant and microsomal pellet of the pancreas was less than 1% of the activity in the respective liver fractions, However, pretreatment of animals with methylcholanthrene or BP at 20 mg/kg, for either 1 day or 3 consecutive days, markedly enhanced the BP hydroxylase activity of pancreatic microsomes over that of controls; the induction in the liver microsomes was less than 2-fold over that of controls. The hydroxylation of BP by pancreatic microsomes was linear with time over a 30-min period, with the rate of hydroxylation dependent on both the enzyme and substrate concentrations.
mesh_terms: D000818:Animals; D001579:Benzopyrene Hydroxylase / Q000096:biosynthesis / Q000378:metabolism; D001580:Benzopyrenes / Q000378:metabolism* / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology; D008861:Microsomes / Q000201:enzymology / Q000378:metabolism; D008862:Microsomes, Liver / Q000378:metabolism; D010179:Pancreas / Q000201:enzymology / Q000378:metabolism*
chemical_list: D001580:Benzopyrenes; D008748:Methylcholanthrene; D001579:Benzopyrene Hydroxylase