Binding of epididymal proteins to the spermatozoa of ram

Glycoproteins and proteins, extracted from the corpus epididymides of rams and linked to colloidal gold, bind specifically onto the plasma membrane of spermatozoa. The sites for the glycoproteins are saturated on spermatozoa after the passage through the corpus epididymidis. Sites for proteins are present at the anterior part of testicular spermatozoa, the whole plasma membrane of the head of spermatozoa from the corpus epididymidis and the posterior part of the head, excluding the equatorial segment, of most spermatozoa from the cauda epididymidis. The technique used is simple, rapid and reliable.