Epidermal growth factor inhibits thymidine incorporation in Ehrlich ascites tumor cells in vivo

The effects of in vivo injection of epidermal growth factor (EGF) on mice bearing Ehrlich ascites tumors have been studied. Epidermal growth factor was rapidly distributed, reached tumor cells and recognized specific cell membrane receptors. The effects of the subcutaneous injection of EGF were manifested by a decrease of measurable membrane receptors and inhibition of thymidine incorporation to TCA-insoluble material. The effect on thymidine incorporation was dose-dependent and independent on the source (murine or human) of EGF. These results suggest that high doses of EGF could eventually be used for inhibition of the cell proliferation in some tumors.