Abstract
We examined whether cardiovascular and oxidative stress responses during mild mental stress change depending on plasma estradiol concentrations. Eight healthy young women (YW, mean±SD age 23.1±0.4 years) and 8 healthy postmenopausal women (PMW, 55.8±1.5 years) underwent mental and physiological stresses, which were evoked by Stroop Color Word Test (CWT) and handgrip, respectively. In young subjects, the experiments were repeated at two different phases of their menstrual cycle (M: menstrual phase, F: follicular phase). Blood Pressure, heart rate, skin blood flow (forehead, forearm) and mental sweating were measured continuously before, during and after the two stresses. Venous blood samples were taken for the measurement of plasma catecholamine, nitric oxide metabolites (NOx), 4-hydroxy-2-nonenal (HNE) and estradiol concentrations. The resting mean arterial pressure (MAP) was higher in PMW compared with in YW at both phases. There was no significant difference in CWT-induced MAP elevation between YW at both phases and PMW. However, MAP returned to the resting level sooner in F than M and PMW. CWT-induced elevation of forehead skin blood flow was enhanced in F compared with M and PMW. The resting level of plasma HNE concentration was higher in PMW than F and M. These findings suggest that estrogen has an effect of mediating vascular and oxidative stresses at rest and during stress. [Jpn J Physiol 54 Suppl:S243 (2004)]
