EFFECT OF CHRONIC INTRACEREBROVENTRICULAR ADMINISTRATION OF AN AROMATASE INHIBITOR ON THE EXPRESSION OF SOCIO-SEXUAL BEHAVIORS IN MALE JAPANESE QUAIL

Aromatase converts androgens into estrogens in the brain of vertebrates including humans. This enzyme is also expressed in other tissues where its action may result in negative effects on human health (e.g., promotion of tumor growth). To prevent these effects, aromatase inhibitors were developed and are currently used to block human estrogen-dependent tumors. In vertebrates including quail, aromatase is expressed in a highly conserved set of interconnected brain nuclei known as the social behavior network. This network is directly implicated in the expression of a large range of social behaviors. Given the potential implication of brain aromatase in a variety of behavioral processes, the primary goal of this study was to characterize in Japanese quail the potential impact of brain aromatase on sexual behavior, aggressiveness and social motivation (i.e., tendency to approach and stay close to conspecifics). A secondary goal was to test the feasibility of long-term delivery of an aromatase inhibitor directly into the third ventricle via Alzet™ osmotic minipumps. We demonstrate that this approach results in the strongest inhibition of both copulatory behavior and sexual motivation ever observed in this species, while other social behaviors were variably affected. Sexual motivation and the tendency to approach a group of conspecifics including females clearly seem to depend on brain aromatase, but the effects of central estrogen production on aggressive behavior and on the motivation to approach males remain less clear.