Effects of a cafeteria diet and starvation of global 14C(U)-glucose disposal.

The label distribution in control and cafeteria-diet fed rats, either in basal conditions or after 24 hours of food deprivation, 10 minutes after the i.v. injection of carrier-free D-14C-(U)-glucose, has been studied. The radioactivity recovered in the different fractions of liver, kidney, heart, striated muscle and white adipose tissue showed comparable patterns of change with starvation in both dietary groups. Most of the radioactivity was found in the free amino acid fraction as well as in proteins, with significant proportions also in lipid and liver glycogen. However, most of the label was lost due to its oxidation, remaining in the combined indicated tissues 10-20% of the injected label. On the whole, cafeteria rats consumed more glucose than controls, the lowest oxidation corresponding to the starved-control group. The amount of glucose oxidized by cafeteria rats was actually comparable to that of fed controls. The availability of other energetic sources--i.e. lipid--allows for an increased glucose utilization in cafeteria rats, even in the starved state.