Elevation of blood levels of zinc protoporphyrin by radiomimetic drugs and friend leukemia virus

Sublethal doses of whole-body irradiation induced the elevation of zinc protoporphyrin (ZPP). Experiments were conducted to determine if recovery from radiomimetic drugs also resulted in elevation of ZPP. Daily injections with hydroxyurea and other cytotoxic drugs for 10 days caused ZPP elevation and a dose of radiation too low to cause ZPP elevation by itself caused ZPP elevation when hydroxyurea was administered prior to irradiation. Friend leukemia virus also brought about an elevation of ZPP. However, not all factors that increased erythropoiesis brought about ZPP elevation. The elevated erythropoiesis in response to hypoxia and the enhanced erythropoiesis that followed administration of folic acid to folic acid-deficient mice was not accompanied by ZPP elevation. (orig.)