SEXUAL DIFFERENCES IN VASOPRESSIN RECEPTOR-BINDING WITHIN THE VENTROLATERAL HYPOTHALAMUS IN GOLDEN-HAMSTERS

In the following studies, the presence of a sexual difference in argin ine-vasopressin (AVP) receptor binding was tested within the ventrolat eral hypothalamus (VLH), an area rich in gonadal steroid receptors. Th e density of AVP receptor binding was estimated by in vitro quantitati ve autoradiography within the entire rostro-caudal extent of the VLH. The density of AVP binding was higher in males than in females at all levels of this area. Furthermore, dependency on testosterone treatment was also compared between gonadectomized males and females. While gon adectomy resulted in a near total disappearance of binding in both mal es and females, testosterone treatment resulted in equally high levels of binding in both sexes. Indeed, a high density of AW receptor bindi ng was observed at all levels of the VLH in both testosterone-treated males and females. These results show that adult female golden hamster s are equally capable as males of expressing high levels of AVP recept or binding in the VLH in response to high levels of testosterone. Toge ther, our results suggest that, while AVP receptor binding within the VLH is sexually different in gonadally-intact animals, these differenc es are not related to differential responsiveness to testosterone, but rather to a differential production and availability of the hormone.