Influence of physiologic oscillation of estrogens on cerebral hemodynamics

The interactions between estrogens and the cerebrovascular system are compl ex and not fully understood. There are evidences suggesting that the hormon es confer protection against cerebral ischemia. Our aim in this study was t o investigate the effects of physiological variations of estradiol plasmati c concentration on cerebral hemodynamics. We investigated cerebrovascular r eactivity to hypercapnia with transcranial Doppler ultrasonography and the breath-holding index method in the right middle cerebral artery of 20 young women during the menstrual and the ovulatory phase, Data were compared wit h those of 20 men matched fur age, The mean value of the breath-holding ind ex was significantly higher (p < 0.001) in females during the ovulatory pha se than in the menstrual phase, In men, values were similar to those of wom en during the menstrual phase. These results suggest that estrogens influen ce the adaptation capacity of the cerebrovascular system. The possible path ophysiological implications of the relationships between sex hormones and c erebral hemodynamics deserve further investigation. <(c)> 2001 Published by Elsevier Science B.V.