Radiation Injury and Recovery in Anagen and Telogen Rodent Hairs

Reduced incorporation of isotope-labeled compounds was studied to assess postirradiation damage and recovery in growing (anagen) and resting (telogen) rodent hairs. Reduced uptake of${}^{3}{\rm H}\text{-}{\rm DL}\text{-serine}$ or${}^{75}{\rm Se}\text{-}{\rm L}\text{-methionine}$ was found to be dose-dependent for hairs in both phases of the cycle. Twofold greater reductions occurred in anagen hairs, as compared to telogen hairs, at given X-ray dosages. No recovery of reduced${}^{3}{\rm H}\text{-}{\rm DL}\text{-serine}$ incorporation was demonstrable in telogen hairs up to 12 days postirradiation. In anagen hairs, however, full restoration of normal amino acid uptake occurred in the same postirradiation period. Some implications of these studies for radiation injury and recovery in proliferative and nonproliferative hair matrix populations are discussed.