The effects of testosterone and its metabolites on sexual behavior and morphology in male and female Japanese quail

Abstract

Adult Japanese quail are sexually dimorphic. Even when implanted with testosterone (T), ovariectomized females fail to copulate and their cloacal glands are smaller than those of males. This may be due to a reduced capacity of the females to transform testosterone into active metabolites (estradiol-17β and 5α-dihydrotestosterone). Indeed, in the male quail, estradiol-17β (E 2) activates copulation whereas 5α-dihydrotestosterone (5α-DHT) activates crowing, strutting and the development of the cloacal gland. To test this hypothesis, we studied the effects of in vivo treatments of male and female quail with the different T-metabolites. Forty-one castrated male and female quail were implanted with subcutaneous silastic implants of T, 5α-DHT, E 2 and E 2 in combination with 5α-DHT. When implanted with these metabolites, females failed to copulate and their cloacal glands remained less developed than those of males. Sexual differences in behavior and morphology thus cannot be entirely explained by sexual dimorphism of the metabolism.