Abstract: 　Objective] To determine the effect of Schistosoma japonicum infection on the testoterone level in the sera from male C57BL/6 mice. [Methods] Radioimmunoassay was used to examine testosterone levels in sera of 9 male mice experimentally infected with Schistosoma japonicum . [Results] The serum testosterone levels reduced significantly in all experimentally infected animals 45 days after infection, as compared with the uninfected controls. [Conclusion] Infection with Schistosoma japonicum decreases testosterone levels in the mouse host.

Key words: Schistosoma japonicum, testosterone, mouse, radioimmunoassay.