Arginine vasopressin regulation in pre- and postpubertal male rats by the androgen metabolite 3 -diol

Pak TR, Chung WC, Hinds LR, Handa RJ. Arginine vasopressin regulation in preand postpubertal male rats by the androgen metabolite 3 -diol. Am J Physiol Endocrinol Metab 296: E1409–E1413, 2009. First published April 21, 2009; doi:10.1152/ajpendo.00037.2009.—Arginine vasopressin (AVP) is a nonapeptide expressed in several brain regions. In addition to its well-characterized role in osmoregulation, AVP regulates paternal behavior, aggression, circadian rhythms, and the stress response. In the bed nucleus of the stria terminalis (BST), AVP gene expression is tightly regulated by gonadal steroid hormones. However, the degree by which AVP is regulated by gonadal steroid hormones in the suprachiasmatic nucleus (SCN) and medial amygdala (MeA) is unclear. Previous studies have shown that AVP expression in the brain of gonadectomized rats is restored with testosterone, 17 -estradiol, and 5 -dihydrotestosterone (DHT) replacement. In addition, we have demonstrated that 3 -diol, a metabolite of DHT, increased AVP promoter activity in a neuronal cell line and that the effects of 3 -diol on AVP promoter activity were mediated by estrogen receptor. To test whether 3 -diol has a physiological role in the regulation of central AVP expression in vivo, we gonadectomized preand postpubertal male rats and followed with once daily injections of estradiol benzoate (EB), DHT-propionate, 3 -diol-dipropionate, or vehicle. The SCN, BST, and MeA were analyzed for AVP mRNA expression using in situ hybridization. In the BST, intact juveniles had significantly fewer AVP-expressing cells than adults. GDX abolished all AVP mRNA expression in the BST in both age groups, whereas treatment with EB restored 80% and DHTP 10% of the AVP expression. Interestingly, 3 -diol-proprionate was more effective at inducing AVP expression in juveniles than in adults, suggesting that the regulation of AVP by 3 -diol might be age dependent.