An immunohistochemical study on estrogen receptor-alpha (er-?)‎ Expression in the rabbit uterus during early pregnancy and pseudopregnancy

Abstract EN

Estrogen is essential factor for establishment of normal pregnancy in mammals.

Estrogenic action in uterus was found to be mediated by intracellular, primarily nuclear receptor called estrogen receptor-alpha (ER-?).

In the current study; immunohistochemistry was used to localize ER-? in the uterus of pregnant and psudopregnant rabbits.

ER-? was strongly expressed in non pregnant uteri in nearly all cellular compartments as luminal and glandular epithelium, stromal cells and myometrial smooth muscle cells.

Marked down regulation of the ER-? in luminal but not in glandular epithelium was observed during early periods of pregnancy and pseudopregnancy.

Weaker glandular staining was only observed during postimplantation periods.

Stromal cells were always immunopositive even after implantation till day twelve of pregnancy.

Myometrium was expressing the receptor till after implantation.

ER-? was always nuclear in immunopositive cells.

Our results revealed that, ER-? was involved in the process of progestational proliferation in the rabbit uterus; in addition, the receptor expression is tissue specific and maternally controlled.