Potentiation of smooth muscle contraction by adrenal steroids.

F Bhadrakom, 1 and Helmer have employed spirally cut strips of rabbit aorta in a bioassay method for estimation of urinary levels of catechol amines. In attempting to use this method for determination of adrenal venous plasma levels of epinephrine and norepinephrine, the possibility arose that adrenal steroids might alter the contraction of rabbit aortic smooth muscle produced by these eatechol amines. This paper describes the effect of five adrenal steroids— hydrocortisone, corticosterone, aldosterone, androsterone, and dehydroisoandrosterone— upon the contraction of the rabbit aortic strip produced by levarterenol (Z-noradrenaline). Although none of the steroids tested produced contraction of the rabbit aortic strip alone, each steroid produced significant potentiation of the contraction of the rabbit aortic strip resulting from levarterenol.