Regulation of acrosomal matrix dispersion in digitonin-permeabilized guinea pig spermatozoa.

Digitonin-permeabilized guinea pig spermatozoa undergo acrosomal matrix dispersion in response to 2.0 mM CaCI2. In this report, the effects of pH and metal ions on matrix dispersion in permeabilized spermatozoa are examined. Calcium-induced dispersion of:he acrosomal matrix was dependent on the calcium concentration; the response was no: observed at concentrations of CaCl2 less than 50 riM. Magnesium could not substitute for calcium and, in fact, had a retarding effect on the cakium-induced response. Matrix dispersion was also found to be pH-dependent. The induction of matrix dispersion was inhibited atpH5.6 and pH 9.5 relative to the responses observed atpH 6.3 andpH 7.8. Nigericin induced acrosomal matrix dispersion in the absence of added calcium,