ABSTRACT
Growth factors and cytokines are small polypeptides which function as intracellular and extracellular signals to regulate the activities of single cells and tissues via their binding to specific receptors. This chapter provides a brief review of the effects of growth factors and, to a lesser extent, of cytokines on mammalian hair growth. It illustrates the growing understanding of how abnormalities in the production and regulation of growth factors and cytokines affect hair follicle formation, hair structure, and the hair cycle to produce abnormal hair or fur. Growth factors, such as epidermal growth factor and transforming growth factor (TFGα), were found to affect the rate of regeneration after burn wounds. Transgenic mice overexpressing TGFβ-l have been produced using a human keratin I promoter vector and a constitutively active mutated TGFβ-1. These transgenic mice had very shiny, tautly stretched skin which restricted the animals' ability to move and breathe.
