The Maturation of Rabbit Epididymal Spermatozoa in Organ Culture: Stimulation by Epididymal Cytoplasmic Extracts

Infertile spermatozoa from the proximal corpus epididymidis do not become fertile when this epididymal segment is cultured 24 h in vitro. Addition of a cytoplasmic extract from the distal corpus significantly increases their fertilizing ability. Extracts prepared from cauda epididymides or from liver were effective; however, liver extract was less effective than extract from cauda epididymides in increasing fertilizing ability. The factor(s) responsible for this effect is not a steroid or another charcoal extractable substance. These observations stress the importance of the epididymal contribution to the maturation of spermatozoa.