2,3-Diphosphoglycerate red cell concentration changes during the menstrual cycle in woman.

The authors showed that 2,3-DPG red cell concentration (2,3-DPG) WAS SIGNIFICANTLY HIGHER DURING THE LAST WEEK Of the menstrual cycle of five women (1.08+/-0.09 mol-,p;Hb-1) (M +/- 1 SE) THAN DURING THE First part and the last but one week of the cycle (0.86+/-0.04 mol-molHb-1, p less than 0.01). PACO2 was significantly lower during the last week of the cycle (36.3+/-1.3 torr) than during the first part and the last but one week of the cycle(40.1+/-0.8 torr, p less than 0.001). This hypocapnia was due to transient hyperventilation in the second part of the menstrual cycle. 5 men were studied during 4 weeks to determinate control values. No change was observed. The 2,3-DGP mean value (1.10+/-0.01 mol-molGb-1) was not significantly different of the values observed in the women during the last week of the cycle. These results suggest that the 2,3-DPG increase during the last week of the menstrual cylce is problably due to a respiratory alkalosis induced by progesterone secretion.