Effect of Pyridine Nucleotides on the 1-14C-Glucose Utilization of Normal Human Red Blood Cells

Abstract

A NUMBER of investigators have shown that disphosphopyridine nucleotide (DPN) and triphos-phopyridine nucleotide (TPN) enhance the metabolism of glucose in liver preparations via the Embden–Meyerhof and pent ose-phosphate (hexose-monophosphate) pathways, respectively1–3. We have found that TPN and reduced triphosphopyridine nucleotide (TPNH) stimulate the 1-14C-glucose metabolism of normal human red blood cells as measured by the increased production of 14CO2 with increasing amounts of the pyridine nucleotides. Since normal human red blood cells contain an Embden–Meyerhof pathway but cannot oxidize pyruvate, the only source of carbon dioxide is from the decarboxylation of carbon-1 in the pentose-phosphate pathway. Therefore, 14CO2 production is a measure of the amount of 1-14C-glucose metabolized via the pentose-phosphate pathway.