Inhibitory Capacity of Supernatants Obtained from Centrifuging of different epididymal mouse Regions

This study was conducted to shed light on to the factors contributing to fertilizing ability of the caput epididymal spermatozoa. In this content, it should be stated that seminal plasma am! epididymal fluid of most mammalians contains inhibitory factors connected to spermatozoa surface. To do this, components of different regions of mouse epididymis centrifuged and a given volume of supernatants was added to capacitated (120 min preincubated) sperm. The eggs obtained from mature mice were inseminated in the presence ,1f the supernatants. The eggs were studied after 5 to 6 hour of incubation to observe the presence of pronuclei. Of the inseminated eggs (257)in the presence of  caput supernatants only 25.49% (64) did not fertilize while the rate for the eggs inseminated in the presence of corpus (276) and cauda (362) ones, increased to 88.51 %(244) and 95.85%(347), respectively.On the basis of the results it could be concluded that proportion of immature spermatozoa in the caput epididymal region is considerably greater than those of the other two.Additionally, the smaller capability of cauda epididymal spermatozoa to fertilize eggs, after vasectomy, could be refered to destruction of inhibitory factors, occurance of acrosome reaction due to long stop in the region.