Human hair follicles display a functional equivalent of the hypothalamic‐pituitary‐adrenal (HPA) axis and synthesize cortisol

Abstract

SPECIFIC AIMSPrevious research has shown that the skin and its major appendage, the hair follicle, are prominent target organs and potent sources of key players along the classical hypothalamic pituitary adrenal (HPA) axis [e.g., of corticotropin-releasing hormone (CRH) and of melanocortins like adrenocorticotropic hormone (ACTH) and α-melanocyte-stimulating hormone (α-MSH)]. Mammalian skin has been shown to possess the full enzymatic equipment for glucocorticoid synthesis. The aim of the present study, therefore, was to explore whether human skin, namely, normal human scalp hair follicles, contain a functional HPA axis, including the synthesis of cortisol and regulatory feedback loops as they characterize the central HPA axis, using microdissected, organ-cultured human scalp hair follicles stimulated with CRH, α-MSH, ACTH, or hydrocortisone.PRINCIPAL FINDINGS1. POMC transcription and immunoreactivity (IR) for POMC products are up-regulated by CRH treatmentFirst, we studied whether CRH (comparable to the ...