Effects of transforming growth factor beta 1 in the hair cycle.

Hair follicle growth is thought to be regulated by a complex interplay of stimulatory and inhibitory signals. From among such signals, we examined the effects of transforming growth factor beta 1 (TGF beta 1) on the murine hair growth cycle. Quantitation of TGF beta 1 per wet tissue weight was performed at different stages of the hair cycle. TGF beta 1 was extracted with 10 mM HCl, and its level was measured with ELISA. The level of TGF beta 1 did not change markedly during the hair cycle. Immunohistochemical observations revealed that hair follicle cells and epidermal cells were negative for TGF beta 1 at all stages of the hair cycle. Mast cells in the dermis were positive throughout the cycle. To confirm whether the proliferation of hair follicles. Our observations suggest that TGF beta 1 is at least partly responsible for regulating hair follicles as a negative growth factor.