Potentiation of Smooth Muscle Contraction by Adrenal Steroids

The rabbit aortic strip preparation of Furchgott was used to test the effect of adrenal steroids upon the muscle contraction produced by 0.1 to 0.2 μg. of levarterenol. The steroids tested were corticosterone, hydrocortisone, aldosterone acetate, androsterone, and dehydroisoandrosterone. Amounts of 1 to 300 μg. were added to the 20-ml. muscle bath. Potentiation was produced by each steroid; the percentage increase of amplitude of contraction was from 36.1 to 74.2 percent. Corticosterone produced consistent potentiation in amounts as small as 5 μg.; 200 μg. of aldosterone acetate was required to produce potentiation. Maximum potentiation was produced by hydrocortisone. The observed potentiation may be due to an effect of adrenal steroids upon transcellular sodium and potassium gradients.