Surface heterogeneity of rat sperm during maturation.

Rat sperm isolated from the caput and caudal epididymis and the vas deferens were subjected to multiple partition in aqueous two-phase systems. The technique was used to reveal heterogeneity of a sperm population with respect to particular surface properties. Sperm from all three regions gave broad distributions indicative of heterogeneous cell populations. Greatest heterogeneity was observed for cauda sperm with caput and vas sperm producing similar distributions. Following multiple partition sperm from different regions of the distribution profiles were immunostained with three antibodies known to recognise maturation antigens. The results show that some antigens are acquired during epididymal transit whilst others are present throughout. The partition (surface heterogeneity) seen cannot therefore be explained solely by the distribution of the antigens recognized by 2D6, 6B2 and 3D5.