Progesterone-Induced Acrosome Reaction: DISCUSSION(5)
The damaged plasma membrane enables labeling of a cytosolic progesterone receptor at the postequatorial region of the sperm head (Figs. 1C and 3B). Only a few deteriorated cells could be detected with a combination of patchy apical labeling together with the postequatorial labeling (probably cells that deteriorated during the AR). The majority of deteriorated cells, however, showed only postacrosomal intracellular P-BSA-FITC binding sites. This could be the case because such cells have shed the apical plasma membrane (with its P-BSA-FITC binding sites) during the AR, prior to deterioration, as is depicted for one sperm cell in Figure 3B. The fact that we often observed P-BSA-FITC-positive free acrosome caps in our microscopical preparations supports this idea. An alternative explanation is that the deteriorated cells did not expose the progesterone receptor prior to deterioration. birth control yasmin
Flow cytometry analysis of P-BSA-FITC conjugate binding to spermatozoa demonstrates three distinct subpopulations during incubation time. One population corresponds to viable spermatozoa that are not stained with P-BSA-FITC. One population corresponds to viable spermatozoa that are positively stained with P-BSA-FITC and a population of nonviable spermatozoa (see Fig. 6). Similar to the observation with fluorescence microscopy, the flow cytometry analyses showed a clear exposure of the progesterone receptor on the sperm surface during the 5-h incubation period. Simultaneously, a subpopulation of spermatozoa demonstrating the progesterone receptor deteriorated and became nonviable during the incubation.