Increased Muscle Permeability to Aldolase Produced by Insulin and by Albumin

Abstract

Insulin and fraction V of serum proteins increased aldolase efflux from isolated rat peroneus longus, a muscle in which fibers are not cut. The effect upon aldolase efflux in this preparation was about as marked as the effect of insulin upon glucose uptake. Since increased aldolase efflux is assumed to result only from increased membrane permeability the data are interpreted to demonstrate that insulin alters muscle membrane, reducing its ability to serve as a barrier to diffusion.