Aggressive behavior in birds: an experimental model for studies of brain-steroid interactions

1. Although testosterone (T) stimulates aggressiveness in males of many vertebrate species, it is now known that the full expression of T actions in the central nervous system requires aromatization to estradiol (E2) and subsequent binding of formed E2 to its receptor. 2. We have recently confirmed these as rate-limiting steps in the control of sex-related and individual differences in aggressiveness of the Japanese quail (Coturnix coturnix japonica). 3. In this review, we describe some of the neuroendocrine factors which control aggression with a focus on our recent studies in quail.