<P> This shedding of the acrosome , or acrosome reaction , can be stimulated in vitro by substances a sperm cell may encounter naturally such as progesterone or follicular fluid , as well as the more commonly used calcium ionophore A23187 . This can be done to serve as a positive control when assessing the acrosome reaction of a sperm sample by flow cytometry or fluorescence microscopy . This is usually done after staining with a fluoresceinated lectin such as FITC - PNA , FITC - PSA , FITC - ConA , or fluoresceinated antibody such as FITC - CD46 . </P>
the process by which the acrosome membranes of sperm break down is known as
acrosome reaction