The comparative effects of cis- and trans-clomiphene and oestradiol-17β on the sialic acid concentration in the uterus, cervix and vagina were studied in rats during experimentally induced delayed implantation. The cis- or 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.
Cis- and trans-clomiphene and oestradiol-17β 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-clomiphene or 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.