[The mechanism of the effect of sex hormones on the reactivity of vascular smooth muscle]

Abstract

Using the method of isometric contraction, the authors studied the effect of in vivo and in vitro application of sex hormones (estradiol, progesterone, and testosterone) on the reactivity of spiral strips of the thoracic aorta and renal artery of rabbits of both sexes to vasoactive substances (noradrenaline, serotonin, and angiotensin). The potential effect of sex hormones on the function of calcium in the mechanism of vascular smooth muscle contraction was verified by indirect methods. On repeated hormone administration also morphological changes were evaluated from several parts of the vascular bed by means of light microscopy. The results suggest marked quantitative and qualitative differences in the effect of sex hormones on the reactivity of the isolated aorta and renal artery of the rabbit. Affecting the transport of calcium in the cell of the vascular smooth muscle is presumably and important factor involved in the mechanism of development of the observed changes.