Two subjects with hyperthyroidism had increased release of oxygen from blood and elevated concentrations of red blood cell 2, 3-diphosphoglycerate. This organic phosphate can be established as the primary regulator of oxygen release from hemoglobin in this and in other clinical conditions with imbalance of oxygen supply and demand.
Miller WW, Delivoria-Papadopoulos M, Miller L, Oski FA. Oxygen Releasing Factor in Hyperthyroidism. JAMA. 1970;211(11):1824-1826. doi:10.1001/jama.1970.03170110030005