The Site of Uptake of Iodine by Hair

The study investigates the uptake of radioactive iodide by mouse vibrissal hairs using a dry autoradiographic technique. It was found that iodide first appears in the hairshaft just below the sebaceous gland orifice, 0.2 to 0.5 mm beneath the skin surface. In contrast, l-cystine-S35 is absorbed in the deeper parts of the hair root near the dermal papilla. Despite significant uptake of both substances, there is minimal overlap in their absorption sites.