Induction of an oncofetal marker protein upon X-radiation of rat mammary glands

Fifty-day-old female Sprague-Dawley rats were given carcinogenic and sub-carcinogenic doses of X-radiation to the mammary glands to evaluate the induction of a 60-kDa oncofetal protein (OFP-60). This protein has previously been shown to be produced in the target organ and released to circulation during chemical carcinogenesis and tumorigenesis. In a time course experiment, the mammary glands of the rats were irradiated with a single dose of 1.85 gray (Gy). The OFP-60 marker protein was detected in peripheral blood at 21 days post-irradiation. Irradiation of the mammary gland with single X-ray doses ranging from 0.22 to 1.85 Gy produced a linear relationship between X-ray dose and plasma concentration of OFP-60 determined at 21 days post-treatment. with the known linear relationship between dose of X-radiation and potential tumor incidence.