The distribution of radioactivity in the various peaks of the acid profiles of the tumor and other tissues of rats bearing Flexner-Jobling tumors has been studied and 60–100 per cent of the total radioactivity can be accounted for either as radioactivity in volatile compounds or in the elements of the acid profile.
The time course of incorporation of radioactivity from acetate-1-C14 into succinate pools induced by malonate in tumors and normal tissues reveals maximal incorporation in normal tissues 2–4 minutes after the intraperitoneal injection of the precursor.
The total radioactivity in the succinate pool accounts for 30 per cent of the total radioactivity within the kidney and about 10 per cent in other tissues. Very high percentages of the total radioactivity are found in peaks 2 and 3 of the acid profiles, in a number of tissues.
The bulk of the count in the Flexner-Jobling tumor remains volatile for 30 minutes after the injection of the precursor. This finding and the very low incorporation of radioactivity in the pool of succinate within the tumor differentiate this tissue from normal heart, lung, spleen, liver, and skeletal muscle.