Student Prize Award Abstract
2003 Poster Paper Award

ORAL CONTRACEPTIVE TREATMENT ALTERED AGGRESSION AND THE SEROTONERGIC SYSTEM IN FEMALE CYNOMOLGUS MONKEYS

J. A. Henderson and C. A. Shively
Wake Forest University, Dept. Pathology/ Comp Med, Wake Forest Univ. School of Medicine, Medical Center Blvd., Winston-Salem, NC, 27157-1040, USA

Oral contraceptives (OCs) are the most widely prescribed and effective of the reversible contraceptive methods. In addition to inhibiting ovulation, OCs alter behavior and central nervous system function in women; however, methodological problems have prevented clear human studies. Thus, in this experiment we investigated the effects of OC treatment on behavior and the central serotonin system in 75 adult female cynomolgus monkeys (Macaca fascicularis) housed in social groups of four to five monkeys per pen. Monkey social groups were randomly divided into either a control or an OC treatment group which was administered a clinically prescribed OC (Triphasil®, levonorgestrel and ethinyl estradiol tablets) for two years. Social behavior was recorded using a focal animal observation method. A fenfluramine neuroendocrine challenge test was performed to assess central serotonergic activity. ANOVA revealed that OC treated animals had increased rates of contact aggression received (p=0.03), time spent in locomotion (p=0.02), and sitting close to another animal (p=0.01), and decreased time spent fearfully scanning (p=0.03). OC treatment decreased the prolactin response to fenfluramine suggesting decreased serotonergic activity (p=0.03). The reduction in serotonergic activity may be associated with the observed changes in behavior, as several studies have demonstrated an association between decreased serotonergic function and changes in social behavior, particularly increased aggression. These results suggest that this triphasic OC disrupts both social behavior and the underlying central nervous system function.