Capacitation of Hamster Spermatozoa by β-Glucuronidase

Abstract

CAPACITATION, or the ability for immediate penetration of the ovum, occurs when epididymal sperm of the golden hamster (Mesocricetus auratus) are incubated in the presence of follicular fluid^1–3. Yanagimachi has reported that sperm motility is maintained by a dialysate of detoxified bovine follicular fluid, but capacitation of the sperm does not occur unless a water-soluble non-dialysable fraction is also provided⁴. The chemical nature of these factors has not yet been determined. Because ovarian follicles, particularly those in atresia, are known to contain lysosomal enzymes⁵, we investigated the effect of a lysosomal preparation from beef liver on hamster epididymal sperm. Finding a striking stimulation of motility and capacitation of the sperm, we went on to test the lysosomal enzyme, β-glucuronidase, which is widely distributed in mammalian tissue including cells of the ovarian follicle⁶. We found that this enzyme duplicated the effect of the lysosomal preparation, as we shall now describe.