Plasma bioactive LH and testosterone profiles in male New Zealand rabbits experimentally infected with Schistosoma mansoni

The effects of Schistosoma mansoni (S. mansoni) infection on plasma levels of bioactive luteinising hormone (LH) and testosterone in the New Zealand rabbit model were studied. S. mansoni infection significantly decreased the pulse frequency (P < 0.05), amplitude (P < 0.05), area under LH curve (P < 0.05) and mean plasma LH concentrations (P < 0.05) on days 42 and 70 post-infection, as compared to values for day 14 pre-infection. Areas under the response curves for plasma testosterone levels decreased significantly (P < 0.05) on days 42 and 70 post-infection in infected animals compared to day 14 pre-infection. In the praziquantel-treated group, the levels of LH and testosterone remained unchanged throughout the experimental period. The pulsatile secretion of LH was completely inhibited in S. mansoni-infected animals 70 days post-infection. These results suggest that the effects on reproductive gonadal hormones caused by S. mansoni in the rabbit model may partly be induced by alteration in pituitary synthesis or release of LH.