FIGURE 6.

A proposed model for 5′-AMP-mediated hypometabolism via erythrocytes. The model indicates altered levels of glycolytic intermediates and adenylates observed. In the erythrocytes, uptake of 5′-AMP drives the production of ADP at the expense of ATP. In turn, glycolytic steps dependent on ATP at hexokinase (HK) were slowed, resulting in the buildup of glucose and decreased production of lactate. The reduction in glycolytic rate will drive the production of 2,3-BPG from 1,3-BPG by the enzyme bisphophoglycerate mutase to stabilize intracellular ATP levels. The increase in 2,3-BPG allosterically reduces the affinity of hemoglobin (Hb) for oxygen, which could explain the rapid and steep decline in VO₂ illustrated by phase I and increased deoxyhemoglobin levels.