SEX-HORMONE CHANGES INDUCED BY THE PARASITE LEAD TO FEMINIZATION OF THE MALE HOST IN MURINE TAENIA-CRASSICEPS CYSTICERCOSIS

Female mice are more susceptible to Taenia crassiceps (TC) infection t han males. However, after a month parasite load increases massively in both genders reaching thousands of parasites per host. The possibilit y of hormonal changes in the infected mice was envisaged. Sex hormones levels were assayed after different periods of infection, the parasit es present in the peritoneal cavity were collected and gonads, uterus and seminal vesicles were weighed. In male mice, serum estradiol incre ased to levels 200 times their normal values whilst those of testoster one decreased 90% relative to controls. The weight of seminal vesicles was significantly diminished. Infected female mice also showed a slig ht increase in estrogen blood levels after 8 weeks of infection and th e weight of the uterus was significantly increased relative to control s. Serum estradiol and testosterone were almost undetectable after gon adectomy. Cytokines such as IL-6 are capable of stimulating aromatase activity and we found that splenocytes from infected mice produced amo unts of IL-6 higher than control as measured by ELISA. In conclusion T . crassiceps infection triggers a feminization process in the infected hosts. The gonads are required for the parasite to induce higher estr ogen synthesis. IL-6 could be involved in the immunoendocrine mechanis m used by the parasite to maintain a highly permissive environment for its rapid growth.