Influence of environmental temperature on the induction of xenobiotic metabolism by beta-naphthoflavone in rainbow trout, Salmo gairdneri.
The response of hepatic microsomal cytochrome P-450 monooxygenase and UDPglucuronosyltransferase to a common inducer, beta-naphthoflavone, was investigated in rainbow trout acclimated to 5 or 17 degrees C. The hepatic microsomal 7-ethoxycoumarin-O-deethylase, 7-ethoxyresorufin-O-deethylase, and benzo[a]pyrene hydroxylase activities, measured at 5 or 17 degrees C, were induced at both acclimation temperatures. Maximum response of 7-ethoxyresorufin-O-deethylase and 7-ethoxycoumarin-O-deethylase activities to beta-naphthoflavone was obtained with doses of 5 mg/kg and above, both in warm- and cold-acclimated trout. In warm-acclimated trout the maximum degree of induction of cytochrome P-450-dependent activities was already evident on the day following treatment with beta-naphthoflavone (100 mg/kg), whereas these activities reached maximum values after 3 days in cold-acclimated fish. Furthermore, the maximum induced values of 7-ethoxyresorufin-O-deethylase and benzo[a]pyrene hydroxylase activities were higher in cold-acclimated than in warm-acclimated fish. beta-Naphthoflavone treatment caused a slight but significant increase (1.6-fold) in UDPglucuronosyltransferase activity in warm-acclimated fish when measured at 5 or 17 degrees C, whereas in cold-acclimated fish a significant elevation was seen only when the activity was determined at environmental temperature (5 degrees C).
D000818:Animals; D001571:Benzoflavones / Q000494:pharmacology*; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis; D004790:Enzyme Induction / Q000187:drug effects; D005260:Female; D005419:Flavonoids / Q000494:pharmacology*; D014453:Glucuronosyltransferase / Q000096:biosynthesis; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology; D012487:Salmonidae / Q000378:metabolism*; D013696:Temperature; D014337:Trout / Q000378:metabolism*; D019324:beta-Naphthoflavone
D001571:Benzoflavones; D005419:Flavonoids; D019324:beta-Naphthoflavone; D003577:Cytochrome P-450 Enzyme System; D014453:Glucuronosyltransferase