Expression of estrogen receptors alpha and beta in term human myometrium

We used immunohistochemistry to compare the expression of estrogen receptors (ERalpha and ERbeta) in term myometria of 32 pregnant women divided in two groups. Group I comprised of 16 women in labour and group II included 16 non-laboring gravidas. We observed cytoplasmatic localization of both ER isoforms and no differences in the ER expression between the two groups of patients. The abundance and specific localization of ERs in human term myometrium seems to be independent of its contractile activity which may point to the specific role of those receptors in late pregnancy myometrium.