Anomalous Greying Effect in Mice with Higher Doses of X-rays

Exposure of mouse hair follicles to 1200, 1300, and 1400 r of x-rays results in delay of hair growth, precocious melanogenesis, and disruption of melanocyte distribution. The diversity of greying responses obtained with 1100 to 1700 r appears to be due to inactivation of radiosensitive follicles rather than to tissue replacement or to displacement of external sheath melanocytes into the hair bulb.