The distribution of estrogen receptor beta is distinct to that of estrogen receptor alpha and the androgen receptor in human skin and the pilosebaceous unit.

Both estrogens and androgens play important parts in skin and hair physiology, although studies of estrogen action in human skin have been rather limited. Recently, a second estrogen receptor (beta) has been identified in many nonclassical target tissues, including androgen-dependent tissues. Therefore, we have revisited the role of estrogens in human skin and hair by comparing the pattern of expression by immunohistochemistry for both estrogen receptors (alpha and beta) and the androgen receptor. Immunolocalization of androgen receptors was only seen in hair follicle dermal papilla cells and the basal cells of the sebaceous gland. Little specific staining of estrogen receptor alpha was seen anywhere except the sebaceous gland. In contrast estrogen receptor beta was highly expressed in epidermis, blood vessels, and dermal fibroblasts, whereas in the hair follicle it was localized to nuclei of the outer root sheath, epithelial matrix, and dermal papilla cells. Serial sections also showed strong nuclear expression of estrogen receptor beta in the cells of the bulge, whereas neither estrogen receptor alpha or androgen receptor was expressed. In the sebaceous gland, estrogen receptor beta was expressed in both basal and partially differentiated sebocytes in a similar pattern to estrogen receptor alpha. There was no obvious difference in the expression of either estrogen receptor in male or female nonbalding scalp skin. The results of this immunohistochemical study propose that estrogen receptor beta and not estrogen receptor alpha is the main mediator of estrogen action in human skin and the hair follicle. Further studies with androgen-dependent skin are required to determine whether estrogen receptor beta has a regulatory role on androgen receptor expression in the hair follicle in parallel with its role in other androgen-dependent tissues.