IN VITRO TRANSFORMATION OF STEROIDS BY HEAD KIDNEY BODY KIDNEY AND CORPUSCLES OF STANNIUS OF RAINBOW TROUT (SALMO GAIRDNERI)

Incubation of 4-14C-labeled pregnenolone, 17α-hydroxyprogesterone, 11-deoxycorticosterone, and androstenedione with homogenates of head kidneys containing interrenal tissue of the rainbow trout (Salmo gairdneri) resulted in the production of 17α-hydroxypregnenolone, 11-deoxycortisol, and cortisol from pregnenolone; 11-deoxycortisol, cortisol, and androstenedione from 17α-hydroxyprogesterone; corticosterone and 18-hydroxy-11-deoxycorticosterone from 11-deoxycorticosterone; and testosterone and 11β-hydroxyandrostenedione from androstenedione. After incubation of progesterone with homogenates of the body kidney, 5α- and 5β-pregnanedione, 3α- and 3β-hydroxy-5α-pregnan-20-one, and 3α- and 3β-hydroxy-5β-pregnan-20-one were obtained as the metabolites of progesterone. When homogenates of corpuscles of Stannius of the rainbow trout were incubated with progesterone or 11-deoxycorticosterone, no corticoid could be detected as metabolite of the substrates, but 5α-pregnanedione and its 5β-isomer were obtained as the main products from progesterone. These results demonstrated the presence of 11β-hydroxylase, 17α-hydroxylase, 18-hydroxylase, 21-hydroxylase, 17β-hydroxysteroid dehydrogenase, Δ5-3β-hydroxysteroid dehydrogenase, C17C20 lyase, and Δ5-Δ4 isomerase activities in the head kidney of the rainbow trout. On the other hand, pregnene-5α- and 5β-hydrogenase activities were predominant in the corpuscles of Stannins as well as in the body kidney of the rainbow trout, while 3α- and 3β-hydroxysteroid dehydrogenase activities were also observed in the body kidney of the fish. © 1969.