Melanogenesis is coupled to murine anagen: Toward new concepts for the role of melanocytes and the regulation of melanogenesis in hair growth

The document from July 1, 1993, discusses the relationship between hair pigmentation and hair growth in mice, emphasizing that melanin production by follicular melanocytes is closely linked to the anagen (growth) phase of the hair cycle and ceases during catagen and telogen phases. It highlights a specific pattern of tyrosinase activity, which is crucial for melanin synthesis, during anagen follicle development. The review suggests that the signals for melanin synthesis and transfer to hair keratinocytes originate within the skin, particularly noting the role of the proopiomelanocortin (POMC) gene, which is active during anagen but not detectable during telogen. POMC is a precursor for molecules that regulate melanocyte activity. Additionally, fibroblasts and keratinocytes produce factors influencing melanocyte behavior. The authors propose that melanocytes may not only contribute to pigmentation but also play a role in regulating hair growth through their interactions with other skin cells. This process is described as a complex coordination of epithelial, mesenchymal, and neuroectodermal interactions.