The kinetics of in situ repair in rat mammary cells.

The kinetics of in situ repair (ISR) was investigated in normal rat mammary epithelial cells exposed in vivo to 8 Gy 137 Cs gamma rays. ISR as measured by transplantation assay was completed by 4 hours after exposure. Although ISR in the three normal epithelial cell types thus far tested differs from repair of potentially lethal damage in tumour cells and cultured fibroblasts in that it affects the shoulder and not the slope of the survival curve, the current study shows that the time course of ISR resembles that for repair of potentially lethal damage in both tumours and fibroblasts.