Microvascular effects of CRH in human skin vary in relation to gender

Males and females have a significantly different life expectancy because of the cardioprotective effects of estrogen. The mechanisms that result in this difference between the sexes are not fully understood. However, stress is a contributing factor to the development of cardiovascular disease, and stress-related factors derived from central or peripheral sources may have differential effects in the modulation of cardiovascular function in males and females. CRH is a central modulator of the stress response and is known to have vasodilator effects in a number of vascular beds. We have examined whether CRH has vasodilator effects in human skin and whether this effect is different between males and females using laser Doppler and iontophoresis. CRH (1 nM) had vasodilatory effects in the skin circulation of both premenopausal females (n = 6) and age-matched males (n = 5), but CRH-induced dilation was significantly more potent in females than males. Acetylcholine (1 nM) and sodium nitroprusside (0.74 nM) induced dilation was not significantly different between males (n = 6) and females (n = 6). This is the first study to demonstrate that CRH acts locally as a vasodilator in human skin circulation and that this response is augmented in premenopausal females. The mechanism by which CRH causes dilation in human skin is presently unknown. However, these data suggest that CRH-induced dilation may be one mechanism by which cardiovascular risk is reduced in premenopausal women.