Carbohydrate metabolism in subjects with cancer.

Abstract

Summary We have determined the plasma disappearance and 14 CO 2 production curves after uniformly labeled glucose- 14 C and palmitate-1- 14 C were given by single injection to five subjects with metastatic malignant disease. The subjects were studied both after an overnight fast and during p.o. glucose loading. The amounts of labeled glucose and palmitate that were metabolized to CO 2 were calculated by kinetic analysis which utilized the best fit of the plasma disappearance and CO 2 production curves. The results were compared with those found in a group of normal subjects on whom identical studies had been carried out. In the experiments carried out after an overnight fast, there were no detectable differences in substrate metabolism between the normal group and the subjects with cancer. When glucose was administered, however, the normal metabolic adjustments were severely limited in patients with metastatic disease. CO 2 production from labeled glucose showed only a modest increase, labeled free fatty acid oxidation decreased less than normal, and CO 2 production from unlabeled substances was unchanged from that found in the fasting state. We conclude that the disposal of glucose under this circumstance is directed toward synthetic rather than oxidative channels.