Role of Testosterone in Host-Parasite Interaction During Murine Experimental Infection of Schistosoma Japanicum.

We analyzed roles of testosterone on susceptibility to infection during murine experimental schistosomiasis japonica. Male C57BL/6 mice infected with Schistosoma japonicum showed marked reduction in serum level of testosterone compared with infection-free male control mice, suggesting that S. japonicum infection suppressed testosterone level in host animals. Potential roles of testosterone in the susceptibility to schistosomiasis were tested by preparing mice in which testosterone levels were artificially manipulated. At 45 days after infection, we observed that male mice with reduced testosterone level showed significantly higher worm burden (p<0.05). The area occupied by granulomas in liver was increased in mice of low circulating testosterone level possibly due to the high worm burden. High level of testosterone also inhibited, to some extent, fecundity of the female parasites. Treatment of infected mice with an inhibitor for testosterone receptor did not alter worm burden, and this suggests that testosterone could have direct effects on the parasites.