Further evidence that androgen aromatization is essential for the activation of copulation in male quail

Abstract

In Experiment 1 male quail ( Coturnix coturnix japonica) with photically regressed testes were implanted intraperitoneally with Silastic tubing containing either testosterone propionate (TP), testosterone (T), androstenedione (AE), 17α-methyltestosterone (MT), estradiol benzoate (EB), dihydrotestosterone propionate (DHTP), 6α-fluorotestosterone propionate (FTP), fluoxymesterone (FM), or cholesterol (CHOL), or were implanted subcutaneously with pellets of FTP. All steroids except EB and FM stimulated proctodeal gland development, and all except MT, EB, and FM stimulated crowing to a significant extent. When administered as Silastic implants, the only androgens that activated copulation were TP, T, and AE. Subcutaneous pellets of FTP also activated copulation. In Experiment 2 male quail with photically regressed testes were injected with TP, TP + ATD (1,4,6-androstatrien-3,17-dione, an aromatase inhibitor), EB, EB + ATD, or oil. ATD completely blocked TP-stimulated copulation, but had no effect on EB-stimulated copulation. These experiments provide further evidence for an aromatization theory of quail copulation.