Differences in inducibility of cytochrome p-4501a1, monooxygenases and glutathione s-transferase in cutaneous and extracutaneous tissues after topical and parenteral administration of β-naphthoflavone to rats

1. 1. The effect of topical and parenteral administration of β-NF to rats on cytochrome P-4501A1, monooxygenases and glutathione S-transferase enzyme activities in various tissues were studied. 2. 2. Topical and I.P. administration of β-NF to rats resulted in variable induction responses (2-28-fold) in various tissues. Benzo(a)pyrene hydroxylase, ethoxyresorufin-O-deethylase, ethoxycoumarin-O-deethylase, and GST activities in liver, kidney and skin were induced to higher extent than in other tissues following both topical and i.p. administration. 3. 3. Western blot analysis of microsomal preparation from β-NF-treated rats using monoclonal antibody to P-4501A1 showed a marked induction of P-4501A1 enzyme protein in skin and liver. 4. 4. These results suggest that both topically as well as parenterally administered xenobiotics may influence drug metabolizing capacity of skin and other tissues.