Attenuated sex steroid receptor expression in fallopian tube of women with ectopic pregnancy

Context
Sex steroid hormone receptor (SHR) dynamics are well-documented in human endometrium but have not been comprehensively studied in Fallopian tube (FT).

Objective
The aim of the study was to compare expression patterns and hormonal regulation of SHR in FT with that described in endometrium and to determine whether SHR expression is altered in FT of women with ectopic pregnancy (EP).

Design
Tissue was analyzed and cultured.

Patients or Other Participants
Women undergoing surgery for benign gynecological conditions (n = 14) and EP (n = 6) participated in the study.

Interventions
Quantitative RT-PCR and immunohistochemistry were used to determine SHR mRNA expression and protein localization, respectively. SHR levels were measured in tubal explant cultures stimulated with estrogen and progestogen.

Results
ER alpha and ER beta mRNAs were constitutively expressed in FT during the menstrual cycle. PR-AB and PR-B mRNAs were decreased in midluteal phase compared to follicular phase. ER alpha, PR-AB, and PR-BmRNAs were down-regulated in human FT in vitro by treatment with progestogen. ER alpha, ER beta 1, ER beta 2, PR, and AR proteins localized to cell nuclei of epithelium, stroma, and smooth muscle of nonpregnant FT. In FT from women with EP, PR-B mRNA was decreased when compared to midluteal FT, and ER alpha protein was not detected.

Conclusions
SHR expression in FT is different from that observed in endometrium recovered at similar stages of the menstrual cycle, and expression in FT from women with EP is also altered compared with normal FT. These data are an important benchmark for furthering the understanding of normal human FT physiology, changes in expression of SHR in FT in response to progesterone, and disorders of FT function, such as EP.