Loss of acid phosphatase from rat spermatozoa as a method for assessing the acrosome reaction

A method is presented for evaluating the extent of the acrosome reaction by measuring the release of acrosomal acid phosphatase from rat spermatozoa during incubation under capacitating conditions. Treatment of spermatozoa with lysophosphatidylcholine or Triton X-100 released the acid phosphatase from the sperm cell. Using this enzymatic method we could not detect an alteration in enzyme activity following 5 h incubation under capacitating conditions. The effect of in vitro capacitation for 5 h in the absence or presence of heparin or ionophore A23187 was studied. Incubation in the presence of heparin (10 micrograms ml-1) caused a 32% increase in enzyme activity. After exposure of the spermatozoa to ionophore A23187 (0.5 microM) 16% increase of enzyme activity could be detected.