Enhanced radiation response of in vitro tumor models to insulin

The presence of insulin during the irradiation of plateau phase baby hamster kidney, Chinese hamster ovary, Ehrlich tumor, human oral carcinoma, human laryngealcarcinoma, and V-79 cells improved radiation response. Insulin was also found to enhance the radiation response of multicell V-79 spheroids. The radiosensitizing effect of insulin is both time and concentration dependent. Additional studies indicate that glucagon-free insulin and the insulin mimicking tripeptide, glycyl-L-histidyl-L-lysine-acetate, also sensitize plateau phase cultures of V-79 cells to radiation