Capacitation of Rabbit Spermatozoa

Abstract

IT was first reported by Chang¹ for the rabbit and by Austin² for the rat that, even when fertilizable tubal ova were surrounded by active spermatozoa, the latter did not penetrate the zona pellucida unless they had been in the female tract for some hours. Chang³ showed that this delay was associated with a physiological change in the spermatozoa themselves, since he found that if the spermatozoa had been previously kept in the uterus of another female for about 6 hr., fertilization proceeded immediately when the ‘Capacitated’ spermatozoa and ova were brought together. In the rat, ‘capacitation’ takes 2–4 hr.^4–6. The following experiments show that the site of ‘capacitation’ is not specific, and that spermatozoa can acquire fertilizing capacity in the spayed female, in the intact male, and in organs quite unrelated to the genital system.