Human Hair Follicles Operate a Functional Peripheral Equivalent of the Hypothalamic-Pituitary-Somatotropic Axis Ex Vivo

This study demonstrates that human scalp hair follicles (HFs) possess a functional peripheral equivalent of the hypothalamic-pituitary-somatotropic (HPS) axis. Researchers found that HFs express key elements of the HPS axis, including growth hormone (GH), growth hormone-releasing hormone (GHRH), and their respective receptors. Ex vivo experiments showed that GHRH stimulates GH production in HFs, mimicking the central HPS axis. Additionally, GH and GHRH treatments influenced the expression of somatostatin (SST) and insulin-like growth factor 1 (IGF-1), indicating a functional feedback loop. The study suggests that targeting GHRH and GH receptors could be a potential therapeutic approach for hair growth disorders, such as telogen effluvium and alopecia areata. The findings highlight the importance of further research into the intrafollicular HPS axis and its role in hair pathology.