Effects of sex steroids on testosterone metabolism, plasma gonadotropins, cloacal gland growth and reproductive behaviour in the japanese quail

Abstract

Castrated male quails, exposed to long days (16L: 8D), were implanted with 10 mm silastic capsules (internal diameter: 1,57 mm) containing testosterone or 5α-dihydrotestosterone (5a-DHT) or they were injected with estradiol benzoate (EB). The effects of these manipulations on cloacal gland growth, plasma levels of gonadotropins (FSH and LH), sexual behaviour and on testosterone metabolism in the brain and in the anterior pituitary were assessed. The cloacal gland size was much increased by testosterone and 5α-DHT and the conversion of testosterone to 5ß-reduced metabolites in the pituitary was depressed by treatments with 5α-DHT and/or EB. Only minor effects were observed in the plasma levels of gonadotropins and in sexual behaviour except crowing, which was stimulated by testosterone and by the combined treatment with 5α-DHT and EB. This study shows that the cloacal gland is more sensitive to androgens than the brain areas that control sexual behaviour through the negative feedback of gonadal steroids. © 1979 Taylor & Francis Group, LLC.