title: Drug metabolism in skin. Comparative activity of the mixed-function oxidases, epoxide hydratase, and glutathione S-transferase in liver and skin of the neonatal rat.
abstract: Aryl hydrocarbon hydroxylase (AHH) activity in the skin of neonatal rats was compared to that in epidermis, dermis, and other body tissues. Following topical application of benzo[a]pyrene (BP) or the polychlorinated biphenyl mixture Aroclor 1254 there was induction of AHH in each tissue studied. There was a greater increase in the activity of skin enzyme as compared to other extrahepatic tissues. When whole-organ activity (pmol of 3-OH-BP per min per whole organ) was considered, skin represented 2%, 21%, and 27% or whole body activity in control, BP-treated, and Aroclor 1254-treated animals, respectively. Skin microsomes from control rats exhibited 2, 0.5, 24, and 6% of corresponding liver microsomal AHH, 7-ethoxycoumarin de-ethylase, NADPH-cytochrome c reductase, and epoxide hydratase activities, respectively. Glutathione S-transferase activity in skin cytosol was 15% of the corresponding hepatic activity. Following topical application of Aroclor 1254 there were increases in the activity of AHH and 7-ethoxycoumarin de-ethylase in the skin and the liver. Glutathione S-transferase (40-60%) and epoxide hydratase (83-94%) activities in neonatal rat liver were induced by skin application of Aroclor 1254.
mesh_terms: D015660:7-Alkoxycoumarin O-Dealkylase; D000818:Animals; D000831:Animals, Newborn; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism; D004851:Epoxide Hydrolases / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D009928:Organ Specificity; D010088:Oxidoreductases / Q000378:metabolism*; D010105:Oxygenases / Q000378:metabolism; D051381:Rats; D012867:Skin / Q000201:enzymology*
chemical_list: D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D010105:Oxygenases; D015660:7-Alkoxycoumarin O-Dealkylase; D001189:Aryl Hydrocarbon Hydroxylases; D009251:NADPH-Ferrihemoprotein Reductase; D005982:Glutathione Transferase; D004851:Epoxide Hydrolases