Possible significance of seminal zinc on human spermatozoa functions

This study has been performed to investigate the possible role of seminal zinc in the regulation of human spermatozoa functions. Sperm cells from fertile men were washed and pooled, and in each cellular suspension we determined: a) spermatozoal uptake of zinc, b) effects of different albumin concentrations on cellular zinc content, c) effects of zinc and albumin on spermatozoal O2 consumption, d) effects of different zinc concentrations on albumin induced acrosome reaction. We observed that increases of extracellular zinc cause corresponding increases of spermatozoal zinc and that albumin exerts an important chelating effect, even at very low concentrations, on cellular zinc content. Zinc also possesses a reversible inhibitory effect on spermatozoa O2 consumption in a dose-related way, and albumin is able to reverse this effect. Albumin-induced acrosome reaction was also significantly reduced by addition of different zinc concentrations. Our findings reveal that zinc exerts an important influence on human spermatozoa functions and suggest that zinc may be involved in the mechanisms that maintain spermatozoa in the transitory quiescent state until penetration in the female reproductive tract.