Blood flow and muscle metabolism: a focus on insulin action

MG Clark, MG Wallis, EJ Barrett… - American Journal …, 2003 - journals.physiology.org
MG Clark, MG Wallis, EJ Barrett, MA Vincent, SM Richards, LH Clerk, S Rattigan
American Journal of Physiology-Endocrinology And Metabolism, 2003journals.physiology.org
The vascular system controls the delivery of nutrients and hormones to muscle, and a
number of hormones may act to regulate muscle metabolism and contractile performance by
modulating blood flow to and within muscle. This review examines evidence that insulin has
major hemodynamic effects to influence muscle metabolism. Whole body, isolated hindlimb
perfusion studies and experiments with cell cultures suggest that the hemodynamic effects of
insulin emanate from the vasculature itself and involve nitric oxide-dependent vasodilation …
The vascular system controls the delivery of nutrients and hormones to muscle, and a number of hormones may act to regulate muscle metabolism and contractile performance by modulating blood flow to and within muscle. This review examines evidence that insulin has major hemodynamic effects to influence muscle metabolism. Whole body, isolated hindlimb perfusion studies and experiments with cell cultures suggest that the hemodynamic effects of insulin emanate from the vasculature itself and involve nitric oxide-dependent vasodilation at large and small vessels with the purpose of increasing access for insulin and nutrients to the interstitium and muscle cells. Recently developed techniques for detecting changes in microvascular flow, specifically capillary recruitment in muscle, indicate this to be a key site for early insulin action at physiological levels in rats and humans. In the absence of increases in bulk flow to muscle, insulin may act to switch flow from nonnutritive to the nutritive route. In addition, there is accumulating evidence to suggest that insulin resistance of muscle in vivo in terms of impaired glucose uptake could be partly due to impaired insulin-mediated capillary recruitment. Exercise training improves insulin-mediated capillary recruitment and glucose uptake by muscle.
American Physiological Society