During acute administration of native glucagon-like peptide-1 (GLP-1), we previously demonstrated central hemodynamic effects in healthy males, whereas renal hemodynamics, despite renal uptake of GLP-1 in excess of glomerular filtration, was unaffected. In the present study, we studied hemodynamic effects of GLP-1 in patients with type 2 diabetes under fixed sodium intake. During a 3-h infusion of GLP-1 (1.5 pmol·kg(-1)·min(-1)) or saline, intra-arterial blood pressure and heart rate were measured continuously, concomitantly with cardiac output estimated by pulse contour analysis. Renal plasma flow, glomerular filtration rate, and uptake/release of hormones and ions were measured using Fick's Principle after catheterization of a renal vein. Urine collection was conducted throughout the experiments at voluntary voiding, and patients remained supine during the experiments. During the GLP-1 infusion, systolic and diastolic blood pressure and cardiac output remained unchanged, whereas heart rate increased significantly. Arterio-venous gradients for GLP-1 exceeded glomerular filtrations significantly, but renal plasma flow and glomerular filtration rate as well as renal sodium and lithium excretion were not affected. In conclusion, acute administration of GLP-1 in patients with type 2 diabetes leads to a positive chronotropic effect, but in contrast to healthy individuals, cardiac output does not increase in patients with type 2 diabetes. Renal hemodynamics and sodium excretion are not affected.
Keywords: blood pressure; cardiac output; glomerular filtration rate; glucagon-like peptide-1; heart rate; renal plasma flow; renal sodium excretion.
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