clinicaltrials.gov Identifier: NCT00356213.

Both procedures markedly improved glucose homeostasis: insulin, GLP-1, and PYY levels increased similarly after either procedure. Our results do not support the idea that the proximal small intestine mediates the improvement in glucose homeostasis.

Background/Aims-Studies in animals suggest a physiological role for glucagonlike peptide-1-(7-36)-amide (GLP-1) in regulating satiety. The role of GLP-1 in regulating food intake in man has, however, not been investigated. Subjects-Sixteen healthy male subjects were examined in a double blind placebo controlled fashion. Methods-The eVect of graded intravenous doses (0, 0.375, 0.75, and 1.5 pmol/ kg/min) of synthetic human GLP-1 on food intake and feelings of hunger and satiety was tested in healthy volunteers. Results-Graded GLP-1 infusions resulted in a dose dependent reduction in food intake (maximal inhibition 35%, p<0.001 v control) and a similar reduction in calorie intake (32%; p<0.001). Fluid ingestion was also reduced by GLP-1 (18% reduction, p<0.01). No overt side eVects were produced by GLP-1, but subjects experienced less hunger and early fullness in the period before a meal during GLP-1 infusion at the highest dose (p<0.05). Conclusions-Intravenous infusions of GLP-1 decrease spontaneous food intake even at physiological plasma concentrations, implying an important role for GLP-1 in the regulation of the early satiety response in humans. (Gut 1999;44:81-86)

Glucagon-like peptide-1-(7-36)-amide (GLP-1) is involved in satiety control and glucose homeostasis. Animal studies suggest a physiological role for GLP-1 in water and salt homeostasis. This study's aim was to define the effects of GLP-1 on water and sodium excretion in both healthy and obese men. Fifteen healthy subjects and 16 obese men (mean body mass index, 36 kg/m2) were examined in a double-blind, placebo-controlled, crossover study to demonstrate the effects of a 3-h infusion of GLP-1 on urinary sodium excretion, urinary output, and the glomerular filtration rate after an i.v. 9.9-g salt load. Infusion of GLP-1 evoked a dose-dependent increase in urinary sodium excretion in healthy subjects (from 74 +/- 8 to 143 +/- 18 mmol/180 min, P = 0.0013). In obese men, there was a significant increase in urinary sodium excretion (from 59 to 96 mmol/180 min, P = 0.015), a decrease in urinary H+ secretion (from 1.1 to 0.3 pmol/180 min, P = 0.013), and a 6% decrease in the glomerular filtration rate (from 151 +/- 8 to 142 +/- 8 ml/min, P = 0.022). Intravenous infusions of GLP-1 enhance sodium excretion, reduce H+ secretion, and reduce glomerular hyperfiltration in obese men. These findings suggest an action at the proximal renal tubule and a potential renoprotective effect.