Distribution of androgen receptor immunoreactivity in vasopressin-immunoreactive and oxytocin-immunoreactive neurons in the male rat brain

Arginine vasopressin-immunoreactive (AVP-ir) neurons in the bed nucleus of atria terminalis (BST) and medial amygdaloid nucleus are very responsive to gonadal hormones. After gonadectomy, these neu-rons lose their AVP immunoreactivity and stop expressing AVP mRNA. Testosterone treatment reverses these changes, acting via androgen as well as estrogen receptor-mediated mechanisms. Although AVP-ir neurons contain estrogen receptor immunoreactivity, it is not known whether they also contain androgen receptor immunoreactivity. To answer this question, brains of male rats were stained immunocy-tochemically for AVP as well as for androgen receptors. In the BST and medial amygdaloid nucleus, respectively, 90.5 % and 91.2 % of the AVP-ir neurons contained androgen receptor immunoreactivity. In contrast, in the suprachiasmatic nucleus, the supraoptic nucleus, and the magnocellular portion of the paraventricular nucleus (PVN), non