Methaemoglobin and erythrocyte reducing systems in high-altitude natives

Abstract

Summary. The stress of chronic hypobaric hipoxia present at high altitudes induces a series of adaptive changes in the intermediate metabolism in erythrocytes of high-altitude natives. Aymaras of the high Andean Plateau are shown to have within erythrocytes: (a) increased activity of NADH₂ (GAPDH) generating stages, (b) decreased activity of NADH₂ (LDH) consuming steps, (c) significantly increased methaemoglobin content, and (d) a large increase in the level of reduced glutathione. These alterations occur also in persons of the same ethnic group residing at low altitude. There is, however, only a moderate elevation of classic haematological parameters (erythrocyte count, haemoglobin and haematocrit) in highland natives. The functional implications of these metabolic changes are discussed with respect to regulation of erythrocyte metabolism.