Phospholipase A of Guinea Pig Spermatozoa: Its Preliminary Characterization and Possible Involvement in the Acrosome Reaction. (guinea pig/spermatozoa/acrosome reaction/phospholipase A)

Abstract

Phospholipase A activity was demonstrated in guinea pig spermatozoa using [U-¹⁴ C] phosphatidyl choline as a substrate. The activity had a neutral pH optimum, was stimulated by Ca²⁺ and low concentrations of detergent, and. was inhibited by EDTA, mepacrine and p-bromophenacyl bromide. Appropriate concentrations of mepacrine and p-bromophenacyl bromide inhibited the acrosome reactions of capacitated spermatozoa without interfering with their motility. These results support the notion that phospholipase A is involved in the acrosome reaction of mammalian spermatozoa.