These findings indicate that, in healthy lean men, the rate of gastric emptying of whey protein is independent of load and determines the initial gastrointestinal hormone response. This study was registered at www.anzctr.org.au as 12611000706976.

Aims/hypothesis A postprandial fall in BP occurs frequently in older individuals and in patients with type 2 diabetes. The magnitude of this decrease in BP is related to the rate of gastric emptying (GE). Intravenous administration of glucagon-like peptide-1 (GLP-1) attenuates the hypotensive response to intraduodenal glucose in healthy older individuals. We sought to determine the effects of exogenous GLP-1 on BP, GE, superior mesenteric artery (SMA) flow and glycaemic response to oral ingestion of glucose in healthy older individuals and patients with type 2 diabetes. Methods Fourteen older volunteers (six men, eight women; age 72.1±1.1 years) and ten patients with type 2 diabetes (six men, four women; age 68.7±3.4 years; HbA 1c 6.6±0.2% [48.5± 2.0 mmol/mol]; nine with blood glucose managed with metformin, two with a sulfonylurea and one with a dipeptidyl-peptidase 4 inhibitor) received an i.v. infusion of GLP-1 (0.9 pmol kg −1 min −1 ) or saline (154 mmol/l NaCl) for 150 min (t=−30 min to t= 120 min) in randomised order. At t=0 min, volunteers consumed a radiolabelled 75 g glucose drink. BP was assessed with an automated device, GE by scintigraphy and SMA flow by ultrasonography. Blood glucose and serum insulin were measured. Results GLP-1 attenuated the fall in diastolic BP after the glucose drink in older individuals (p<0.05) and attenuated the fall in systolic and diastolic BP in patients with type 2 diabetes (p<0.05). GE was faster in patients with type 2 diabetes than in healthy individuals (p<0.05). In both groups, individuals had slower GE (p<0.001), decreased SMA flow (p<0.05) and a lower degree of glycaemia (p<0.001) when receiving GLP-1. Conclusions/interpretation Intravenous GLP-1 attenuates the hypotensive response to orally administered glucose and decreases SMA flow, probably by slowing GE. GLP-1 and 'short-acting' GLP-1 agonists may be useful in the management of postprandial hypotension.