Changes in skin structure associated with elevated androgen levels in maturing male brown trout, Salmo trutta L.

Increases in epidermal and dermal thickness, and a reduction in the number of superficial goblet cells, occur in the skin of maturing male brown trout. These changes are correlated with rising levels of plasma 11‐ketotestosterone and it is suggested that control of integumental structure in male fish is mediated by androgenic steroids during sexual maturation.