REGION-SPECIFIC EFFECT OF TESTOSTERONE ON OXYTOCIN RECEPTOR-BINDING IN THE BRAIN OF THE AGED RAT

We reported previously a significant reduction of oxytocin (OT) recept or binding in the brain of 20-month old rats relative to 3-month old o nes. The present study shows that testosterone treatment of aging rats restores normal adult levels of OT receptor binding in the olfactory tubercle and in the hypothalamic ventromedial nucleus, but not in the caudate-putamen. These data indicate that the reduced plasma testoster one found in 20-month old rats is responsible for the loss of OT recep tors in the olfactory tubercle and hypothalamic ventromedial nucleus, whereas other aging-related mechanisms may account for the decrease of OT receptor binding in the caudate-putamen. (C) 1998 Elsevier Science B.V.