Effect of low dose rate irradiation on the division potential of cells in vitro. VII. Human fibroblasts from young and adult donors.

Lung and skin fibroblasts from young and adult donors were irradiated with low dose rate ionizing radiation. Experiments show that in fibroblastlike cells from human adult donors there are three main types of response: irradiation can decrease only the total number of cells produced, it can also decrease the number of subcultures, and in some instances it can prolong the growth potential. Previous experiments suggested that these responses are genetically determined. They may have implications concerning the donor's proneness to cancer.