The effect of cis- and trans-clomiphene citrate on sialic acid in the uterus, cervix and vagina of rats during delayed implantation.

The comparative effects of cisand trans-clomiphene and oestradiol-17\g=b\on the sialic acid concentration in the uterus, cervix and vagina were studied in rats during experimentally induced delayed implantation. The cisor trans-isomer of clomiphene caused a progressive dose-dependent increase in sialic acid in the uterus and cervix whereas vaginal sialic acid decreased with increase in the dose of the respective compounds. Cisand trans-clomiphene and oestradiol-17\g=b\all caused a sharp increase in the sialic acid content of the uterus, cervix and vagina 6 hr after the administration of the respective compounds. There was a decrease in sialic acid in all the three tissues at subsequent time intervals in cis-clomipheneor oestradiol-treated rats. The oestrogenic effects of trans-clomiphene lasted even up to 48 hr in all three reproductive tract tissues, indicating that trans-clomiphene is more oestrogenic than the cis-isomer.Differences in the response of the uterus, cervix and vagina to administration of the compounds are discussed in relation to their embryological origin.