The effect of epididymal and testicular fluids on the fertilising capacity of testicular and epididymal spermatozoa.

It is possible that the fertilising capacity of spermatozoa in the epididymis is influenced by the epididymal secretion. We have studied this problem by obtaining spermatozoa before entry into the epididymis and after passage through it, incubating both types of spermatozoa in fluids from the rete testis and cauda epididymidis and then checking their fertilising capacity. While spermatozoa from the rete testis were infertile, rete testis fluid did not decrease the fertilising capacity of epididymal sperm from the cauda epididymidis. Fluid from the cauda epididymidis did not promote the fertilising capacity of testicular spermatozoa. These results are discussed in the light of the current understanding of epididymal physiology.