Binding of steroids to human spermatozoa and its possible role in contraception

The binding of steroids to human ejaculated spermatozoa and the effect of steroids bound to spermatozoa on sperm migration and motility in vitro was examined. A correlation between progestogens that bind to steroid-binding sites on human spermatozoa and progestogens that inhibit sperm migration was established. The results indicated that there is a direct and specific steroid effect on human spermatozoa, as some steroids such as progesterone, lynestrenol, and norethynodrel markedly inhibited sperm migration and motility, whereas other steroids such as estrone had no detectable effect on sperm migration and motility. The significance of these findings was discussed in relation to the contraceptive action of steroids applied directly to the lumen of the female genital tract.