Abstract # 90:

Scheduled for Thursday, June 20, 2013 07:00 PM-09:00 PM: Session 9 (SG Foyer ABC) Poster Presentation


EFFECTS OF AROMATASE INHIBITION AND ANDROGEN ACTIVITY ON SEROTONIN AND BEHAVIOR IN MALE JAPANESE MACAQUES (MACACA FUSCATA)

C. L. Bethea, A. L. Reddy, N. D. Roberston and K. Coleman
Oregon National Primate Research Center, 505 NW 185th Ave, Beaverton, OR 97006, USA
line
     Aggression has been linked to androgens and serotonin function. However, there is little evidence to support treatment of aggressive disorders with serotonergic agents. To further understand the role of androgens in the regulation of serotonin, we manipulated circulating androgens and aromatase activity in male Japanese macaques living in social groups. Monkeys were castrated and treated with placebo, testosterone(T), T+Dutasteride (5areductase inhibitor), or T+Letrozole (non-steroidal aromatase inhibitor) for 3 months (n=5/group). Afterwards, two groups were further treated with Flutamide+ATD (androgen antagonist plus steroidal aromatase inhibitor) or dihydrotestosterone (DHT)+ATD for 3 months. Behavioral observations were made during treatments. At the end of each 3-month treatment period, animals underwent a fenfluramine challenge to determine the availability of serotonin. Fenfluramine-induced prolactin secretion in the T-treated group was significantly higher than other groups (p<0.0001). Complete block of aromatase with ATD significantly reduced the prolactin/serotonin response in the presence or absence of DHT. Androgen administration did not correlate with serotonin availability suggesting that serotonin is not regulated by androgens. Serotonin correlated with aromatase activity and presumed production of neural estradiol (p<0.0008; r squared=0.95). Androgen treatment significantly increased aggressive behavior (p=0.0006) and yawning (p=0.0016) compared to pre-treatment. There was no correlation between these behaviors and prolactin/serotonin. Together, the data suggest that aromatase activity and production of neural estradiol support serotonin production and that androgens increase aggression by another mechanism in macaques.