[Age-related characteristics of the role of the endothelium in the response of vascular smooth muscles to hormones. The role of ultrastructural changes].

The experiments performed on isolated preparations of femoral artery and aorta of the mature and old rats as well as on those of coronary arteries of adult and old subjects failed to reveal direct participation of endothelium in the realization of insulin and vasopressin effects on the smooth muscles of the vessels studied. However, the endothelium modulated their influence on the vessels in the mature age. The lack of modulating effect of the endothelium in old age may be a result of its structural changes and thickening of a hemato-cellular barrier of the vessel wall observed by electron microscopy.