Essential and nonessential fatty acid oxidation in mice bearing Ehrlich ascites carcinoma.

We tested the hypothesis that mobilized (essential) free fatty acids (FFA) are spared from oxidation in cancer-bearing animals. We injected tracers [1-14C] linoleate, [1-14C] palmitate and NaH14CO3 intravenously as single rapid doses in separate groups of mice bearing Ehrlich ascites tumor (EAT) and controls, and measured breath 14CO2. The data from NaH14CO3 injections were used to develop kinetic, compartmental models of the HCO3--CO2 systems. These models were integrated with our earlier model of plasma FFA turnover for control and EAT-bearing mice. The integrated multicompartmental models were then fitted to breath 14CO2 data from mice injected with tracer FFA to compare the rates of FFA oxidation. FFA were not spared from an oxidative fate in our cancer-bearing vs normal animals; moreover, essential FFA were not preferentially spared from oxidation compared to non-essential FFA in the cancer-bearing mice.