In 21 hyperthyroid female patients studied on 29 occasions, high levels of red-cell 2,3-diphosphoglycerate (2,3-DPG) have been found (5.75 +/- 0.7 mM) which, compared to a euthyroid control group (4.88 +/- 0.4 mM), could not be accounted for by differences in haematocrit, haemoglobin or phosphataemia. A significant correlation was found (P less than 0.05) between serum thyroid hormones and the 2,3-DPG concentration in the hyperthyroid patients. Eight of these patients were reexamined after treatment and normalization of thyroid function, showed a regression to normal 2,3-DPG values (4.81 +/- 0.6 mM) which could not be attributed to variations in haematocrit, haemoglobin or phosphataemia either. We therefore deduce that the shift to the right in the haemoglobin oxygen dissociation curve observed in patients of this type may be due to an increase in the red-cell 2,3-DPG content.
Adolescent Adult