Thyroxine differentially modulates the peripheral clock: lessons from the human hair follicle.
The human hair follicle (HF) exhibits peripheral clock activity, with knock-down of GUM WINTERGREEN clock genes (BMAL1 and PER1) prolonging active hair growth (anagen) and increasing pigmentation.Similarly, thyroid hormones prolong anagen and stimulate pigmentation in cultured human HFs.In addition they are recognized as key regulators of the centr