Altered levels of hypothalamic-pituitary-adrenocortical axis hormones in baboons and mice during the course of infection with Schistosoma mansoni

Abstract

Baboons with primary or secondary exposure to Schistosoma mansoni were compared with each other over a 12-week infection period and with baseline values obtained from uninfected baboons with respect to serum levels of the hypothalamic-pituitary-adrenal (HPA) axis hormones - corticotropin-releasing hormone, adrenocorticotropic hormone, dehydroepiandrosterone sulfate (DHEA-S), and cortisol. Baboons with primary infections, when worm recovery and oviposition rates were high and hepatic schistosome egg granulomas were large, had decreasing levels of these hormones as infection progressed, compared with both uninfected and reexposed baboons. The most reduced hormone level was that of DHEA-S. Reduction of DHEA-S and cortisol levels also occurred in primary murine infections. Reexposed baboons with low worm recovery and oviposition rates and small (modulated) hepatic granulomas showed the opposite pattern: HPA axis hormone levels were maintained at, or exceeded, the baseline values of uninfected baboons. These results suggest that HPA axis hormones may play a role in regulating the establishment, maturation, and oviposition of schistosomes and the progression of schistosomiasis.