INDUCTION OF CYP2M1 AND CYP2K1 LAURIC ACID HYDROXYLASE-ACTIVITIES BY PEROXISOME PROLIFERATING AGENTS IN CERTAIN FISH SPECIES - POSSIBLE IMPLICATIONS

In many higher vertebrates, species and gender-specific sensitivity to peroxisome proliferating agents (PPAs) and their toxic effects has be en described. Sensitivity may correlate with the induction of lauric a cid hydroxylase (LAH) activity. In rainbow trout (Oncorhynchus mykiss) LAH hers been identified with at least two cytochromes P450, CYP2M1 a nd CYP2K1. Previously, bluegill (Lepomis macrochirus) and catfish (Ict alurus punctatus) had been shown to produce CYP2M1 and CYP2K1 immunore active protein induction upon treatment with PPAs. The current researc h extends that observation by demonstration of the associated lauric a cid hydroxylase activities after exposure to PPAs. Male bluegill and c atfish were treated using a single i.p. injection with olive oil vehic le or ciprofibrate (a model PPA; 100 mg kg(-1)) or clofibrate (less po tent PPA) 48h prior to microsome preparation. Olive oil-treated female catfish liver and kidney microsomes metabolize lauric acid to a great er extent than male microsomes (83 vs 40% and 77 vs 5%, respectively). Male bluegill liver and male catfish kidney exhibit significant induc tion of specific LAH after PPA treatment. These observations, taken to gether with previous work in mammals, may portend possible adverse con sequences to sensitive fish species exposed to environmental chemical contamination by PPAs. (C) 1998 Elsevier Science Ltd. All rights reser ved.