The effect of N-(methoxy polyethylene glycol) rho-hydroxymercuribenzamide, a polymeric sulfhydryl group reagent, on spermatozoan motility.

The water-soluble, polymeric sulfhydryl group reagent N-(methoxypolyethylene glycol) rho-hydroxymercuribenzamide (Mw 5000) inhibited the motility of human spermatozoa. Its activity profile was very similar to that of rho-hydroxymercuribenzene sulfonate, a charged sulfhydryl group reagent that is a very poor membrane penetrant. These results suggest that functional sulfhydryl groups of the spermatozoan membrane are easily accessible and externally oriented on the membrane surface.