PURIFICATION, CHARACTERIZATION AND REGULATION OF A MALE-SPECIFIC CYTOCHROME-P450 IN THE RAINBOW-TROUT KIDNEY

Male rainbow trout kidney (Oncorhynchus mykiss) during the late reproductive stage displays considerably higher levels of cytochrome P450 than that of the female. Two P450 forms, with molecular weights of 54 000 and 52 000 (designated P450 KM1 and KM2, respectively), were partially purified from the male kidney. Specific antibodies were raised against the P450 KM2 form and used with a Western blot technique to demonstrate the virtual absence of this P450 form in female and juvenile kidney microsomes. Treatment of juvenile trout with androgens (11-ketotestosterone being the most potent) increased the renal cytochrome P450 content as well as progesterone 16alpha-hydroxylase and ethoxycoumarin-O-deethylase activities. Androgen treatment of juvenile trout also induced the P450 KM2 in the kidney, as revealed by Western blotting. Thus, the male rainbow trout kidney during the late reproductive stages expresses at least one sex-specific P450 form which is regulated by circulating androgens.