Outer root sheath cells secrete oxytocin for hair growth promotion and stem cell proliferation

Oxytocin is a hormone that is primarily produced in the hypothalamus, as well as in the mammary glands, uterus, intestines, and skin. Generally, this hormone acts on the cells surrounding the tissues to maintain homeostasis. Furthermore, oxytocin acts on hair follicles and enhances the hair growth-promoting ability of dermal papilla cells. In this study, we investigated the presence of oxytocin-producing cells in hair follicles and verified the autocrine/paracrine effects of oxytocin. We demonstrated that outer root sheath cells produce oxytocin, which increases the hair growth-promoting potential of dermal papilla cells. Oxytocin also acts on outer root sheath cells, resulting in stem cell proliferation within these cells. This suggests that oxytocin affects both hair growth promotion and stem cell proliferation within hair follicles. These findings are expected to contribute to our understanding of the mechanisms underlying hair follicle homeostasis.