The reproductive endocrine response to Plasmodium vivax infection in Hondurans

Reproductive physiology and endocrinology change with the onset of illness and injury in a variety of species, including humans. To assess the human reproductive endocrine response to malaria, serial serum samples were collected from 8 male and 9 female residents of Honduras infected with Plasmodium vivax (plus 19 male and 23 female healthy age-matched controls) and were analyzed for associations between testosterone, parasitemia, and cytokine levels. Because testosterone has been negatively associated with measures of immune function under various circumstances, it was hypothesized that testosterone would be directly associated with P. vivax parasitemia and inversely associated with proinflammatory cytokine levels. The findings presented here suggest that 1) testosterone levels are positively associated with P. vivax parasitemia in adult males, and 2) males infected with P. vivax exhibit significantly lower testosterone levels and significantly higher cortisol levels than healthy individuals. Depressed androgen levels during physiologic perturbations may be an advantageous, adaptive host response to ameliorate immunosuppression by higher testosterone levels and to curb the use of energetic resources for metabolically expensive anabolic functions.