Changes in tumour cell selenite (75Se) affinity due to irradiation.

The uptake of 75Se sodium selenite in the liver and tumour tissue of irradiated Wistar rats was studied by radiation measuring methods and radiochromatography. In in vitro experiments liver slices were incubated in selenite solution following irradiation of the liver. The uptake in proteins diminished by 11% as compared with the unirradiated rats. The in vivo 75Se uptake in Ehrlich ascites tumour cells was 71% of that of the controls, when the selenite was administered intravenously after irradiation. The in vivo accumulation of selenite in proteins of Guérin tumours after irradiation was 62% of that in the controls. The radiochromatogram pattern showed a distinct difference between the irradiated and unirradiated tumours. These results are in accord with the clinical 75Se-scintigraphy findings, which show a clear decrease in Se-accumulation after irradiation.