Androgen metabolism in skin and skeletal muscle of the rainbow trout ( Salmo gairdnerii) and in accessory sexual organs of the spur dogfish ( Squalus acanthias)

Abstract

The in vitro metabolism of testosterone, 4-androstene-3,17-dione (androstenedione) and dehydroepiandrosterone by skin and muscle from the rainbow trout ( Salmo gairdnerii), and by skin and accessory sexual tissues from the spur dogfish ( Squalus acanthias) was studied. In trout skin, testosterone was transformed mainly into 5α-dihydrotestosterone together with smaller amounts of 5α-androstane-3α, 17β-diol, androstenedione, 5α-androstane-3,17-dione and androsterone. Androstenedione was transformed mainly into 5α-androstane-3,17-dione with smaller amounts of testosterone, 5α-dihydrotestosterone, androsterone and 5α-androstane-3α,17β-diol. Dehydroepiandrosterone was transformed to 5-androstene-3β,17β-diol with trace quantities of androstenedione and 5α-androstane-3,17-dione. Unidentified polar nonconjugated metabolites and traces of steroid glucuronides were formed from the three substrates. The patterns of steroid metabolism were similar in dorsal and ventral skin, and in dorsal skin from male and female, adult and immature fish. Most of the 5α-reductase activity in the skin was in the dermis, only a small fraction of the total activity being in the epidermis. The trout muscle converted testosterone into 5α-dihydrotestosterone but in much lower yields than did skin. The skin, clasper, sperm sac and vas deferens of an adult male spur dogfish converted testosterone to 5α-dihydrotestosterone and androstenedione, though in much lower yields than did trout skin. Androstenedione was converted into testosterone, 5α-androstane-3, 17-dione and androsterone, while dehydroepiandrosterone was converted into 5-androstene-3β,17β-diol. No metabolism of testosterone was detected in the skeletal muscle of the dogfish.