Demonstration of acrosomal membranes using the hypo-osmotic swelling test

Summary. The state of the acrosomal membranes in human spermatozoa was studied by means of the hypo-osmotic swelling test and indirect immunofluorescence using anti-boar outer acrosomal membrane antibodies. The swelling phenomenon observed in the acrosomal region was characterized by expansion of the plasma membrane without modification of the outer acrosomal membrane.