The effects of 11-ketotestosterone and testosterone on the skin structure of brown trout, Salmo trutta L.

11-Ketotestosterone and testosterone were administered by intraperitoneal implants to immature brown trout. Physiological levels of circulating androgens were maintained over a period of 4 months and this resulted in changes in skin structure which resembled those occurring in maturing male brown trout. 11-Ketotestosterone promoted both epidermal and dermal thickening, and markedly reduced the number of superficial goblet cells, whereas testosterone stimulated only epidermal thickening. The relative roles of these two androgens in the normal maturational processes of brown trout are discussed.