Uterine Changes during Capacitation in the Golden Hamster

Abstract

‘CAPACITATION’ was defined by Chang¹ as the final maturation of spermatozoa in the female genital tract. Since Chang's report considerable research has been directed towards this phenomenon^2,3. Capacitation has been observed outside the female tract in such areas as the eye or urinary bladder⁴ as well as in vitro with follicular fluid⁵ or eosinophils⁶. The viability of ejaculated sperm is determined by factors such as levels of oestrogen and progesterone⁷, and the phase of the oestrous cycle, including the different positions in the female genital tract⁸. Hunter⁹ has recently demonstrated in hamsters that ejaculated spermatozoa exposed to oestrous uterus underwent capacitation with a high rate of zona penetration. He concluded that an incubation effect occurred directly between the uterine environment and the spermatozoa. Even though the epididymal sperm were capacitated, they were not very fertile⁹. It seems that for normal fertilization the uterine environment and seminal plasma are indispensable factors. In studying mammalian fertilization I became interested in the role of the uterine epithelium in capacitation. This preliminary report describes uterine changes during capacitation. A detailed report will be published elsewhere.