The present experiments were performed to elucidate the acute effects of intravenous infusion of glucagon-like peptide (GLP)-1 on central and renal hemodynamics in healthy men. Seven healthy middle-aged men were examined on two different occasions in random order. During a 3-h infusion of either GLP-1 (1.5 pmol·kg−1·min−1) or saline, cardiac output was estimated noninvasively, and intraarterial blood pressure and heart rate were measured continuously. Renal plasma flow, glomerular filtration rate, and uptake/release of hormones and ions were measured by Fick's Principle after catheterization of a renal vein. Subjects remained supine during the experiments. During GLP-1 infusion, both systolic blood pressure and arterial pulse pressure increased by 5 ± 1 mmHg ( P = 0.015 and P = 0.002, respectively). Heart rate increased by 5 ± 1 beats/min ( P = 0.005), and cardiac output increased by 18% ( P = 0.016). Renal plasma flow and glomerular filtration rate as well as the clearance of Na+ and Li+ were not affected by GLP-1. However, plasma renin activity decreased ( P = 0.037), whereas plasma levels of atrial natriuretic peptide were unaffected. Renal extraction of intact GLP-1 was 43% ( P < 0.001), whereas 60% of the primary metabolite GLP-1 9-36amide was extracted ( P = 0.017). In humans, an acute intravenous administration of GLP-1 leads to increased cardiac output due to a simultaneous increase in stroke volume and heart rate, whereas no effect on renal hemodynamics could be demonstrated despite significant extraction of both the intact hormone and its primary metabolite.
Eucommia ulmoides (Tochu) and its extract geniposidic acid reduced blood pressure and improved renal hemodynamics
