Functional role of sperm surface glutathione S-transferases and extracellular glutathione in the haploid spermatozoa under oxidative stress.

On the sperm surface, glutathione S-transferases (GSTs) exist as oocyte binding proteins but their detoxification function in this unique cell type is not known. Using H(2)O(2)- and 4-hydroxynonenal-induced sperm dysfunction models, this study demonstrates that the sperm surface GSTs are able to use extracellular reduced glutathione to inhibit the loss of functional competence of goat spermatozoa; however, in the presence of GST inhibitors, they are unable to do so. In the context of susceptibility of spermatozoa to oxidative stress, this finding that strategically located sperm surface GSTs are important for maintaining the functional competence of sperm is relevant to studies on male infertility.