INHIBITION OF SEXUAL-BEHAVIOR IN MALE-MICE INFECTED WITH TAENIA-CRASSICEPS CYSTICERCI

Prominent estrogenization and deandrogenization ensue in male mice as a consequence of experimental intraperitoneal infection with Taenia cr assiceps cysticerci. The impact of these endocrine changes upon sexual behavior was explored in a group of infected Balb/c male mice at week ly intervals for 15 wk and compared with the behavior of otherwise pai red, nonparasitized male mice. Mounting, intromission, and ejaculation responses markedly declined as infection progressed. Six weeks after infection, none of the infected mice displayed ejaculation, the number of mounts and intromissions gradually decreased, and their latencies increased, until, by the 13th wk, none of the parasitized mice showed any sexual response toward female mice. Fifteen weeks after infection, the number of metacestodes per host increased to a couple of thousand , the mean serum estradiol level was approximate to 50 times higher th an the normal value, and testosterone fell to 5% of its normal level. To fully assess that the inhibition of sexual behavior resulted from t he decrease in testosterone levels, a group of 8-wk-infected mice rece ived testosterone, and complete restoration of their sexual behavior w as observed. Inhibition of masculine sexual behavior during the infect ion period is the result of hormonal changes, estradiol being ineffect ive in maintaining copulation.