An Estrogen Receptor Pathway Regulates the Telogen-Anagen Hair Follicle Transition and Influences Epidermal Cell Proliferation

The study demonstrated that the estrogen receptor pathway in the dermal papilla regulated the transition from the telogen (resting) to anagen (growth) phase in hair follicles. Topical application of 17-β-estradiol to mice skin arrested hair follicles in the telogen phase and inhibited hair growth, while the inactive stereoisomer 17-α-estradiol did not. Conversely, treatment with the estrogen receptor antagonist ICI 182,780 induced hair follicles to enter the anagen phase, promoting hair growth. Immunohistochemical staining showed that estrogen receptor expression in the dermal papilla was highest during the telogen phase. The findings suggested that the estrogen receptor pathway influenced hair follicle cycling and that factors associated with anagen follicles affected epidermal cell proliferation.