Chromate Inhibition,in Erythrocytes,of Chemically Stimulated Increases in Glucose Oxidation via the Hexosemonophosphate Pathway (HMP) ∗

Abstract

Summary

Increases in glucose oxidation via the hexosemonophosphate pathway (HMP) may be induced in erythrocytes by many and diverse chemical compounds. This research was initiated on the hypothesis that insofar as they are specific inhibitors of glutathione reductase, Na₂CrO₄ and 2,-5-dinitrobenzoic acid (DNBA) should have similar discriminatory inhibitory effects against chemically stimulated increases in erythrocyte HMP rates. These were estimated, for both intact and hemolyzed rat erythrocytes. in terms of ¹⁴CO₂ formed from labeled glucose or glucose-6-phosphate. In the labeled glucose tests. DNBA inhibited only those increases in HMP rate which were induced by hydrogen peroxide plus azide, or by GSSG, while chromate inhibited all chemically induced increases in HMP rate tested. Substitution of labeled glucose-6-phosphate did not result in change in pattern re DNBA inhibitions, but did lead to loss of most chromate inhibitions. These various findings are in accord with the concepts that DNBA is a fairly specific erythrocyte GSSG-R inhibitor, while chromate inhibits not only this enzyme but also at least one reaction essential to the HMP, e.g., glucose phosphorylation.