Steroid transformations by the corpuscles of Stannius and the body kidney of Salmo gairdnerii (Teleostei)

Abstract

The corpuscles of Stannius and the body kidney of the rainbow trout, Salmo gairdnerii, convert in vitro at 11.5° progesterone-4- 14C into labeled 11-deoxycorticosterone, 5α-pregnanedione, and 5β-pregnanedione, in addition to a number of unknown metabolites. Steroids were identified by their mobilities on thin-layer chromatograms, derivative formation, and recrystallization to constant specific activity with corresponding authentic preparations. Comparison of the product yield-time curves indicates that, under identical conditions, the amount of 11-deoxycorticosterone formed in the incubates of body kidney was at least six times greater than in those of Stannius corpuscles. More 5β-pregnanedione than 5α-pregnanedione was produced by the kidney, whereas the converse occurred with the Stannius corpuscles. 11β- and 17α-Hydroxylase activities were absent in both tissues, and steroid conjugation was also not observed. On the basis of these findings, any assignment of distinctive corticosteroidogenic function to the corpuscles of Stannius of the rainbow trout seems unjustified.