Sexual behavior and serum levels of prolactin, testosterone, and estradiol in young and old rhesus males.

ABSTRACT

It has been suggested that increased prolactin levels may contribute to decreased libido in aging male primates. To test this hypothesis, the association of sexual performance and serum prolactin levels was determined in young (10 year) and old (25.7 year) male rhesus macaques. Old males displayed significantly lower levels of sexual behavior than young males but their serum prolactin levels were not significantly higher. The correlation between prolactin levels and different measures of sexual behavior also were not significant for either old or young males. These data suggest that elevations in prolactin levels do not significantly contribute to the age-related decline in sexual performance in rhesus males.