Steroid metabolism by embryonic tissues of Arctic charr, Salvelinus alpinus

High-performance liquid chromatography analysis of extracts of Arctic charr (salvelinus alpinus) eggs revealed the presence of several steroids, predominantly progestogens together with testosterone. Yolk sac embryos were incubated with tritiated progesterone ([3H]P4) or 17-hydroxyprogesterone ([3H]17OHP) to examine the ability of the embryos to metabolize progestogens in vitro; both progestogen precursors were converted to various free and conjugated steroids metabolites (sulfates and glucuronides). [3H]P4 was completely metabolized to form steroids that coeluted with standard 11-oxygenated androgens, corticosteroids, progestogens, and some other unidentified metabolites. This report also describes the biosynthesis of 17,20 beta-dihydroxy-4-pregnen-3-one and 17,20 beta-dihydroxy-4-pregnen-3-one 20-sulfate by embryos of Arctic charr that were incubated with 17OHP.