FC-04   ESTROGEN RECEPTORS AND ESTROGEN EFFECTS IN THE DERMAL PAPILLA OF HUMAN HAIR FOLLICLES

MJ Thornton, LD Nelson, 1AH Taylor, R. Karoo, 2AG Messenger Dept Biomedical Sciences, University of Bradford, Bradford, UK, 1Dept Obstetrics & Gynecology, University of Leicester, UK, 2Dept Dermatology, Royal Hallamshire Hospital, Sheffield, UK.

Estrogens influence the hair cycle, yet the cellular sites and mechanisms of action are still poorly understood. Radioactive estrogens have been localised to the follicular dermal papilla in rodents; however, whole skin binding studies have reported differences in estrogen binding that reflects both body site and the hair cycle. Therefore, we have investigated the expression of the two estrogen receptors (ERalpha and ERbeta) in human hairy and non-hairy skin, and cultured human dermal papilla (DP) cells using immunohistochemistry and RT-PCR. Furthermore, the biological effect of estrogens on the secretion of soluble factors by cultured human DP cells was assayed using human epidermal keratinocytes. The expression of ERalpha and ERbeta was compared in sections of paraffin embedded hairy scalp skin and nonhairy facial skin, and DP cells cultured onto glass slides, by immunohistochemistry. DP cells (n=5) were incubated in phenol-free, serum-free DMEM in the presence of vehicle control (0.0001% alcohol), or a range of steroids for 24 h. The media was collected and its effect on keratinocytes assayed using a 3H-thymidine assay. RNA was extracted from the DP cells for RT-PCR. ERbeta was the predominant estrogen receptor expressed in hairy skin, while ERalpha was expressed in non-hairy skin. Cultured DP cells derived from scalp expressed both receptors in vitro, however, ERbeta was expressed in the nucleus while ERalpha was only seen in the cytoplasm and perinuclear region. RT-PCR confirmed that ERalpha was expressed in 4/5 DP cell lines. Conditioned medium collected from these cells demonstrated that the secretion of soluble factors could be modulated by physiological levels of estrogens, which had an inhibitory effect on epidermal keratinocytes. These results provide further evidence that estrogens exert their effects on the hair cycle via the dermal papilla. Furthermore, both ERalpha and ERbeta may have important roles in estrogen action in the human follicular dermal papilla.