STEROIDS OF A CHONDROSTEAN: IDENTIFICATION OF INTERRENAL TISSUE IN THE AMERICAN ATLANTIC STURGEON, ACIPENSER OXYRHYNCHUS MITCHILL, BY HISTOLOGICAL AND HISTOCHEMICAL METHODS

Abstract

SUMMARY Yellow bodies scattered throughout the kidney tissue and posterior cardinal veins of the American Atlantic sturgeon Acipenser oxyrhynchus Mitchill were examined by histological and histochemical methods. Their histology resembled that of interrenal tissue, rather than that of corpuscles of Stannius. The tissue was assayed histochemically for 3β-, 3α-, 11β-, 20β- and 20α-hydroxysteroid dehydrogenase (HSD) activity. Intense 3β-HSD activity was observed in the yellow bodies when dehydroepiandrosterone and pregnenolone were employed as substrates. Very weak 3α-HSD activity was observed with androsterone as a substrate. No 11β-HSD activity was observed with cortisol and corticosterone as substrates, and no 20α- or 20β-HSD activity when 20α- or 20β-hydroxyprogesterone respectively were employed as substrates. These studies suggest that the yellow bodies found in the posterior cardinal veins and kidney tissue of A. oxyrhynchus Mitchill are true interrenal tissue.