Accession Number : ADA019513

Title :   Increased 2,3-Diphosphoglycerate During Normocapnic Hypobaric Hypoxia,


Personal Author(s) : Cymerman,Allen ; Maher,John T. ; Cruz,Julio C. ; Reeves,John T. ; Denniston,Joseph C.

Report Date : 05 DEC 1975

Pagination or Media Count : 30

Abstract : Maintenance of normal plasma pH at high altitude (HA) by acetazolamide has been shown to prevent the HA-induced change in 2,3-diphosphoglycerate (DPG) and P50. To establish whether this phenomenon occurs if hypocapnia is prevented, five subjects (Group I) and four subjects (Group II) were exposed to 440 torr with 3.7% CO2 supplemented and 455 torr with no CO2 supplemented for five days, respectively. Similar alveolar oxygen tensions were maintained in both groups. Group I P50s were significantly increased on days 2-5, while no changes were observed in Group II until day five. Both groups had significant elevations in DPG above sea-level values after two days. Mean corpuscular hemoglobin concentrations (MCHC) remained within normal limits during the first two days, then decreased significantly below sea-level values in Group I (days 3-5) and Group II (days 4-5). Thus prevention of respiratory alkalosis by CO2 supplementation is accompanied by increases in P50 and DPG; these changes occur independently of changes in MCHC.

Descriptors :   *Hypoxia, *High altitude, *Hypobaric conditions, *Stress(Physiology), Respiration, Barometric pressure, Carbon dioxide, Phosphates, Metabolism, Erythrocytes, pH factor, Biochemistry

Subject Categories : Biochemistry
      Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE