The effect of hormones on Trichomonas vaginalis.

The hormonal milieu can alter susceptibility to infection. The effect of hormones on Trichomonas vaginalis was studied utilizing axenically cultured clinical isolates. Oestrogens, in physiological concentrations, decreased the growth of the organisms and their attachment to mammalian cells in vitro, and acted as a chemorepellent. The specificity of these effects was verified by their being blocked with anti-oestrogens, by the dose- and time-dependency of the responses, and by the lack of effect with other hormones. These results suggest that oestrogens may decrease the virulence of T. vaginalis; however, interactions between oestrogens and mammalian cells may promote the development of infection. Thus complicated interactions between hormones, micro-organisms and mammalian cells must determine whether exposure to oestrogens predisposes to or prevents the development of infection.