STEROID-METABOLISM IN FISH - IDENTIFICATION OF STEROID MOIETIES OF HYDROLYZABLE CONJUGATES OF CORTISOL IN THE BILE OF TROUT SALMO-GAIRDNERII

Intraarterial injection of [3H]cortisol in the trout Salmo gairdnerii resulted in accumulation of radioactive catabolites in the gall bladder bile. The catabolites were present mainly as water-soluble conjugates of polar derivatives of cortisol. The steroid moieties, released by β-glucuronidase and aryl sulfatase, of the conjugates, were identified, in order of their quantitative importance as tetrahydrocortisone, 20β-cortolone, tetrahydrocortisol, and 5β-dihydrocortisone, cortisol, and cortisone. The identity of the steroids indicated the action of a 4-ene-5β-reductase, 3α-hydroxysteroid dehydrogenase, 20β-hydroxysteroid dehydrogenase, and 11-hydroxysteroid dehydrogenase. There was no evidence of 5α-reduction or oxidative cleavage of the sidechain. © 1979.