Glutathione and caffeine antagonize the sperm-immobilizing effect of a vaginal contraceptive

Abstract

The concentration-dependent inhibition of Neosampoon, a vaginal contraceptive, on ejaculated human sperm motility was studied with a transmembrane migration method. Caffeine (5mM), glutathione (5mM) and glutathione (15mM) all reactivated the motility of Neosampoon-immobilized sperm. Caffeine (5mM) was more potent than glutathione in antagonizing Neosampoon; there was no difference between the potency of 5mM- and 15mM-glutathione. Human sperm motility could be a model for studying the interaction of membrane-active drugs, including the protective effect of glutathione against membrane-disrupting agents.

PIP: This study investigated the antagonizing effect of both caffeine and glutathione on the sperm-immobilizing ability of Neosampoon, a vaginal contraceptive. The transmembrane migration method, which is effective for analyzing drug effects on human sperm motility, was used. The concentration of Neosampoon that decreased sperm motility to 50% of the control ratio was obtained, and the differences between the motility-reactivating effects of 5 mM caffeine, 5 mM glutathione, and 15 mM glutathione and phosphate-buffered saline on neosampoon-treated sperm were analyzed. All 3 mixtures reactivated the motility of neosampoon-immobilized sperm; however, was more potent that glutathione. There was no difference between the potency of 5 mM and 15 mM glutathione. Glutathione appeared to reactivate the immobilized sperm rather than prevent sperm from being immobilized. It is noted that increasing sperm motility through drugs does not necessarily enhance fertility, however, since sperm structure may become disrupted. The sperm membrane appears to be the site of action shared by caffeine and glutathione, although the definite mechanisms of their effects on sperm motility remains unclear. It is suggested that human sperm motility could provide a model for studying the interaction of membrane-active drugs, including the protective effect of glutathione against membrane-disrupting agents.