Hair growth and hair pigmentation processes have yet to be completely understood. The role of the follicular melanocytes in these processes is not yet clear. Studies have been made to clarify the fate of follicular melanocytes at the end of growing phase, or to identify the location of the cell reservoir that repopulates the new lower follicle at the end of the telogen phase during the hair follicle cycle. Furthermore, it has yet to be demonstrated whether these cells are responsible for some molecular communication signals underlying the changes observed in the hair follicle structure during the hair growth cycle. Some factors have been described for the participation of essential processes to melanocyte biology. The anti-apoptosis protein, Bcl-2, has been shown to be important for maintaining the appropriate life span of melanocytes. SCF/kit pathway has been cited as a primary mechanism for regulating both proliferation and differentiation of melanocytes. On the other hand, the action mechanisms of androgens on hair follicle cells have been objects of study in order to explain how these hormones participate in the regulation of hair growth and hair pigmentation. The aim of this review is therefore to discuss currently known aspects involving hair follicle melanocyte biology.
hair follicle; genes; Bcl-2; immunohistochemistry; melanocytes; pigmentation
