Estrogen receptor expression and neuronal nitric oxide synthase in the clitoris and prepucial gland structures of mice

Abstract

Purpose ERα is the predominant form of estrogen receptor expressed in uterine and vaginal tissue of the murine female reproductive tract. Expression of both isoforms has been detected in vaginal tissue and in the ovary. Estrogen receptors were seen in basal and suprabasal cells of vaginal epithelium and epidermis of labia minora Understanding the locations of the different isoforms of the ER within genital structures may elucidate mechanisms of genital growth and development. It is well known that the sensory condition of the vulva epithelium is highly influenced by estrogen status with enlargement of the genitosensory field in response to this hormone. Estrogens may also prove crucial to the maintenance of urogential sensitivity. Their ability to promote the growth of neurons has been established. Abundant literature has reported on nitric oxide in the context of the internal female reproductive tract and penis, few studies have investigated the female external genital structure or the clitoris. The aim of this work is to study the presence of estrogen receptors (ER), as well as n-NOS in the mouse clitoris. Materials and methods Immunocytochemical studies specific for Estrogen Receptor-α, Estrogen Receptor-β, and nNOS were performed on a series of sections of the pelvic area including the prepucial glands and clitoris of ten mice. Selected sections were also stained with Masson's trichrome. Results ERα was expressed predominantly by the glandular epithelium as well as in the glandular tissue, preputial and apocrine glands. ERα was observed in the nuclei of stromal cells around the cavernous tissue and near the epithelium of the clitoris. ERβ immunostaining was only detected in few cells located in the vascular lumen of the cavernous tissue of the clitoris. nNOS immunostaining was detected in the clitoris, the preputial glans and the connective tissue. Conclusions ERα, ERβ isoforms and neuronal NOS are present in the clitoris and prepucial glands of female mice in different cellular localizations and with differing levels of receptivity. Functional studies would further elucidate the role of receptor functions and their relationship to neuronal expression of nitric oxide.