Alterations of Red-Cell Glycolytic Intermediates and Oxygen Transport as a Consequence of Hypophosphatemia in Patients Receiving Intravenous Hyperalimentation

Abstract

Within seven to 10 days after initiation of total intravenous hyperalimentation with solutions lacking added inorganic phosphate, five of eight adults were found to be significantly hypophosphatemic (serum inorganic phosphate less than 1 mg per 100 ml). Associated with this hypophosphatemia was a decrease in erythrocyte glucose-6-phosphate, fructose-6-phosphate, 3-phosphoglyceric acid, 2-phosphoglyceric acid, phosphoenolpyruvate, 2,3-diphosphoglycerate and adenosine triphosphate, and a marked increase in the concentration of "total triosre phosphates." The reduction in 2,3-diphosphoglycerate and adenosine triphosphate was accompanied by a striking increase in the red cell's affinity for oxygen. In an additional patient studied prospectively, the changes in erythrocyte metabolism were initially manifested by a slight rise in the "total triose phosphates," which was rapidly followed by alterations similar to those described above. These findings suggest that in vivo red-cell glucose metabolism is carefully regulated by the serum inorganic phosphate concentration and that this regulation appears to occur primarily at the glyceraldehyde-3-phosphate dehydrogenase step.