Red cell oxygen transport in man in relation to gender and age

P50 values, the O2-partial pressure at 50% O2-saturation of hemoglobin, 2,3-DPG, hematological parameters and the plasma concentrations of sexual hormones were determined in 135 subjects of both sexes aged from 10 to 60 years. P50 was significantly higher in sexually mature women than in men, but did not differ between sexes before puberty and after menopause. In females P50 increased with sexual maturation by about 2 mmHg (0.27 kPa). RBC, Hb and Hct remained unchanged. In males Hb-O2-affinity, RBC, Hb and Hct increased with aging. In sexually mature females 2,3-DPG was significantly higher (2 mumol/gHb) than in males, although before puberty and postmaturity no difference was found. In males, 2,3-DPG increased slightly with maturation although P50 decreased. P50 values (pH = 7.4) correlated positively with red cell 2,3-DPG only when data from all groups were pooled (r = 0.330, P less than or equal to 0.0001). Hb was negatively correlated with P50 (r = 0.221, P less than or equal to 0.01). The data suggest a sex hormone and maturation induced influence in the development of the red cell O2-transport system. Estrogens seem to favour a decrease in Hb-O2-affinity rather than an elevation in O2-transport capacity, whereas androgens do the reverse.