Speaker Abstract

Insulin and Endothelial Function: Diabetes and Hypertension

J. H. McNeill, Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, B.C. V6T 1Z3.

The endothelium is recognized as an important modulator both physiologically and in pathological states. Stimulation or inhibition of release of endothelial factors (e.g. nitric oxide) can markedly affect physiological and pharmacological responses. We have been interested in the role, of insulin and insulin resistance in the control of blood pressure. Insulin resistance has been implicated in diabetes, coronary artery disease, obesity, hypertension, hyperlipidemia and atherosclerosis. Using two models of hypertension, the SHR and the Fructose-Hypertensive (FH) rat, we have shown that hyperinsulinemia occurs in these models prior to the onset of hypertension. Decreasing insulin resistance by using vanadium compounds, metformin or pioglitazone decreases both insulin levels and the elevation in blood pressure indicating an improvement in insulin sensitivity. Endothelin is increased in FH animals and blockade of endothelin receptors results in a decrease in blood pressure as does chemical sympathectomy. A diminished NO release may also be involved. Insulin resistance can affect a number of processes that leads to the development of hypertension. (Supported by grants from the HSFBCY, CDA and MRC)