MALE REPRODUCTIVE SYSTEMS UNDER CHRONIC FLUOXETINE OR TRIMIPRAMINE TREATMENT

Adult male Long-Evans rats (n = 9 per group) received daily exposure f or 4 weeks to fluoxetine (0.75 mg FLUOX/kg body weight) or trimipramin e (1.6 mg TRIMI/kg body weight). Separate tests of copulation, sexual motivation, and intermale aggressive behaviors were used to evaluate f unctional changes during chronic exposure to either typical or atypica l antidepressant drugs with more or less serotonin specificity. Circul ating hormones, primary and secondary sex structures, and concentratio ns of dopamine (DA) and serotonin (5-HT) from mesolimbic tissue were a ssessed at necropsy. Results of tests with estrous females and untreat ed males revealed progressive disruption to sexual performance and agg ressive responsiveness over time of treatment with TRIMI and, to a les ser extent, with FLUOX. By contrast, motivation, testosterone, and all measures of reproductive physiology were indistinguishable from contr ols. Ratios of transmitter metabolites relative to the parent compound s indicated similar reductions of 5-HT turnover with FLUOX and TRIMI. However, influences on DA turnover were significantly less with FLUOX than with TRIMI. Conclusions are that long-term intervention with anti depressant drugs may disrupt sociosexual exchanges without compromisin g male rats' interest in sexual contact or integrity of their reproduc tive physiology. Lessened disruption of sociosexual behaviors with thi s regimen of chronic FLUOX treatment may be related to the greater sel ectivity on serotonin relative to dopamine turnover.