Sequential expression of glutathione-S-transferase isoenzymes during hair growth phases in mice and their relationship to caldesmon, phosphotyrosinase and VIP receptor protein.

The hair follicle is a structure showing a very unique cycling of its epithelial components. It is innervated by an abundance of peptidergic nerves, and neuroendocrine cells occur within the epithelium or in close proximity to it. Recently, it has been suggested that hair growth may be regulated by neuropeptides. We therefore investigated the relationship of VIP receptor expression to intracellular phosphotyrosinase and caldesmon involved in the control of growth and differentiation and metabolizing isoenzymes of the glutathione-S-transferase (GST) family alpha, mu, and pi during induced anagen of C57 BI-6 mice by immunohistochemistry. It was demonstrated that GST isoenzymes were expressed sequentially in the bulge area and the inner hair root sheath as well as in the sebaceous gland epithelium. Caldesmon was present during the early anagen phases within the bulge region, as was phosphotyrosinase. However, phosphotyrosinase expression decreased in late anagen, and recovered again in post-epilation telogen. VIP receptor was expressed within the bulge area during anagen V, but was absent during the other cycle phases. These results suggest a relationship of protein expression to hair cycle phases and in particular a physiological function of VIP/VIP receptor in terminating the extensive hair follicle growth during anagen I to IV.