5β-Dihydrotestosterone is weakly androngenic in the adult Japanese quail (Coturnix coturnix japonica)

Adult male castrated quail received injections of 0 or 2 mg of 5β-dihydrotestosterone (β-DHT) for 14 consecutive days. These treatments were combined with daily injections of 0.1, 0.5, or 1.0 mg testosterone (T). Control birds were injected with the same volume (0.2 ml) of propylene glycol which was the solvent for all steroids. The cloacal gland area and the sexual activity of all birds were repeatedly measured during the period of injections. At the end, the sternotracheal muscles of all males were also weighed. Treatment with T stimulated the cloacal gland growth and increased the sternotracheal muscle weight. β-DHT injections also produced a weak, though quite consistent stimulation of these parameters. The effects of the two steroids were additive, and did not interact with each other. By themselves, β-DHT injections were ineffective on behavior, but they potentiated the stimulating action of 0.5 mg T administration. These results indicate that β-DHT cannot be considered as an inactive steroid in male birds.