Neuroestrogens and female sexual behavior

The ovaries are often thought of as the main and only source of estrogens involved in the regulation of female behavior. Estrogens are produced by the aromatization of testosterone. Although this enzyme is less abundant than in males, this enzyme is expressed and active in the brain of females where it is regulated by similar mechanisms as in males. Early work had shown that estrogens produced in the ventromedial hypothalamus are involved in the regulation of female sexual behavior in musk shrews. Yet the question of the role of central aromatase in general had not received much attention until recently. In this talk, I will first review early work and recent evidence supporting a role for central aromatization in the regulation of physiological and behavioral processes in females. Then I will present recent data from our lab supporting a role for non-ovarian estrogens in the regulation of female sexual behavior in Japanese quail. Together, these data support the notion that in females brain aromatase is not simply a non-functional vestige of evolution and provide support for the importance of locally produced estrogens for brain function in females.