Abstract
In healthy subjects, we recently demonstrated that during acute administration of GLP-1, cardiac output increased significantly, whereas renal blood flow remained constant. We therefore hypothesize that GLP-1 induces vasodilation in other organs, for example, adipose tissue, skeletal muscle, and/or splanchnic tissues. Nine healthy men were examined twice in random order during a 2-hour infusion of either GLP-1 (1.5 pmol kg-1 min-1) or saline. Cardiac output was continuously estimated noninvasively concomitantly with measurement of intra-arterial blood pressure. Subcutaneous, abdominal adipose tissue blood flow (ATBF) was measured by the 133Xenon clearance technique. Leg and splanchnic blood flow were measured by Fick's Principle, using indocyanine green as indicator. In the GLP-1 study, cardiac output increased significantly together with a significant increase in arterial pulse pressure and heart rate compared with the saline study. Subcutaneous, abdominal ATBF and leg blood flow increased significantly during the GLP-1 infusion compared with saline, whereas splanchnic blood flow response did not differ between the studies. We conclude that in healthy subjects, GLP-1 increases cardiac output acutely due to a GLP-1-induced vasodilation in adipose tissue and skeletal muscle together with an increase in cardiac work.