Erythrocyte adenosine triphosphate depletion during voluntary hyperventilation.

Area of Science:

• Physiology
• Biochemistry
• Hematology

Background:

• Chronic hypophosphatemia impairs erythrocyte function by depleting adenosine triphosphate (ATP) and 2,3-diphosphoglycerate (2,3-DPG).
• Erythrocyte incubation in alkaline solutions also leads to ATP depletion.
• Hyperventilation induces both hypophosphatemia and alkalosis.

Purpose of the Study:

• To investigate the effects of acute hyperventilation on red blood cell (RBC) organic phosphates, shape, deformability, and osmotic fragility.
• To determine the impact of combined hypophosphatemia and alkalosis on erythrocyte metabolism and function.

Main Methods:

• Voluntary hyperventilation for 20 minutes in human subjects.
• Measurement of red blood cell ATP, 2,3-DPG, plasma inorganic phosphorus, and blood pH before, during, and after hyperventilation.
• Assessment of red blood cell shape, deformability, and osmotic fragility.

Main Results:

• Red blood cell ATP decreased by an average of 42% during hyperventilation.
• Blood pH increased by 0.2 units, and plasma inorganic phosphorus decreased by 46%.
• Red blood cell 2,3-DPG, shape, deformability, and osmotic fragility remained unchanged.

Conclusions:

• Acute hyperventilation leads to an isolated, rapid fall in red blood cell ATP, driven by the combined effects of hypophosphatemia and alkalosis.
• The observed ATP depletion is comparable to that seen with complete inhibition of red blood cell glycolysis in vitro.
• RBC 2,3-DPG levels and cellular integrity are not significantly affected in acute hyperventilation.