LACK OF EFFECT OF SUPPLEMENTAL DIETARY SELENIUM ON TIME TO DEVELOPMENT OF RADIATION-INDUCED CUTANEOUS TUMORS IN RATS

Sprague-Dawley 8-week-old male rats received a single dose of 1425 cGy to the skin of the back using a 6 meV electron beam. Three days later they were randomized into three groups receiving supplemental dietary selenium as sodium selenite at levels of 0 ppm, 1 ppm, and 2 ppm selenium. Cutaneous tumors first appeared 33 weeks after irradiation and the experiment was terminated at 63 weeks. A wide variety of epithelial and connective tissue tumors developed. There was no significnt difference in the time to development of epithelial or connective tissue tumors between the three groups. Thus, under the conditions of this experiment an inhibitory effect of dietary selenium on radiation-induced skin tumors was not evident.