Acrosome Loss From the Rabbit Spermatozoon in Relation to Entry Into the Egg

In the golden hamster, Chinese hamster, guinea-pig and Libyan jird, a morphological change is evident in the acrosomes of spermatozoa that have reached the ampulla of the Fallopian tube, and spermatozoa that have passed into or through the zona pellucida of the egg appear to lack acrosomes altogether (Austin & Bishop, 1958a, b). Consistently, both Moricard (1960) and Hadek (1963), working with the electron microscope, reported lack of acrosome in rabbit spermatozoa that have attained the perivitelline space, though Hadek described a spermatozoon in the thickness of the zona pellucida that still showed remnants of acrosomal membranes. On the other hand, Adams & Chang (1962) were unable to discern any change in the acrosomes of living rabbit spermatozoa obtained from the Fallopian tube, and Bedford (1963) concluded that the morphological changes he detected in the acrosomes of tubal and uterine rabbit