Women and men show marked differences in cardiovascular risk profile and outcome. Women experience fewer cardiovascular events than men before menopause, but this relationship seems to reverse at menopause. These disparities are probably due to hormonal factors, especially the female sex hormone estrogen seems to have a protective influence on the development of atherosclerotic plaques premenopausal. The underlying mechanisms of the effect of estrogens on the vessel wall are still insufficiently investigated. In this study, menopause related effects on leukocyte distribution and function as well on platelets and their aggregational response will be evaluated.