Oxygen equilibrium curves on blood within 6 h from sampling have been estimated from polarographic measurements of oxyhemoglobin concentration, in 13 male 14- to 50-yr old Sherpas residing at 3,850 m above sea level (Kumjung, Nepal). In samples with red blood cell counts = 4.7 ± 0.8 (SD) x 106/mm3, total hemoglobin concentration [Hb] = 17.0 ± 1.9 g/dl, and hematocrit = 53.3 ± 5.0, the mean oxygen half-saturation of hemoglobin (P50) (pH = 7.4 and PCO2 = 40 Torr) was 27.3 ± 1.8 Torr. The P50 of altitude Sherpas was not significantly different from that of acclimatized lowlanders (28.2 ± 1.3; n = 7), sea-level Caucasian residents (26.5 ± 1.0; n = 17), and Sherpas at sea level (27.1; n = 3). The 2,3-diphosphoglyceric acid-to-hemoglobin concentration ratio ([2,3-DPG]/[Hb]) in altitude Sherpas was 1.22 ± 0.03, the same as that of acclimatized Caucasians (1.22 ± 0.10). The Bohr effect measured for the blood of one altitude Sherpa by the ratio Δlog P50/ΔpH was -0.32 and -0.45 at PCO2 levels of 40 and 20 Torr, respectively. These values are not significantly different from those found in Caucasians at sea level where Δlog P50/ΔpH was -0.35 and -0.42, respectively. It is concluded that the P50 in native highlanders is not significantly different from that observed in sea-level dwellers. [2,3-DPG]/[Hb] at altitude, both in natives and in newcomers, is 20% higher than in sea-level residents.
|Number of pages||5|
|Journal||Journal of Applied Physiology Respiratory Environmental and Exercise Physiology|
|Publication status||Published - 1979|
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