The oxidation of isotopically labeled glucose, lactic acid, and palmitic acid was studied in slices of transplanted tumors by measurement of incorporation of radioactivity in the respiratory carbon dioxide. It was found that the oxidation of these substances proceeded in tumors at rates within the range of a representative group of normal tissues. Participation of the citric acid cycle in the oxidation of glucose and palmitic acid was shown by inhibition experiments with trans-aconitate and by the formation of radioactive citric acid as an intermediate. It was concluded that the oxidation of carbohydrate and fatty acid by intact tumor cells is qualitatively and probably also quantitatively similar to that of normal tissues.
Aided by grants from the National Cancer Institute of the National Institutes of Health, Public Health Service; the American Cancer Society, on recommendation by the Committee on Growth of the National Research Council; and the U.S. Atomic Energy Commission (Contract No. AT [30-1] 777).