Relations between the fertilizing ability, motility and metabolism of epididymal spermatozoa

This paper compares the principal modifications taking place in spermatozoa during epididymal transit in several species. The relations between changes in the epididymal medium and modifications in the metabolism, motility and/or fertility of spermatozoa are reviewed with particular reference to spermatozoon forward motility. The fertilizing ability of motile testicular and epididymal spermatozoa has been described. It is suggested that the maturation process may induce a series of spermatozoal changes in cyclic AMP content, external membrane composition and nuclear structure throughout the genital tract; these changes would be under the control of the epididymal epithelium. The origins of these phenomena are practically unknown.