title: Effects of exogenous glucagon-like peptide-1 on blood pressure, heart rate, gastric emptying, mesenteric blood flow and glycaemic responses to oral glucose in older individuals with normal glucose tolerance or type 2 diabetes.
abstract: OBJECTIVE
  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; HbA1c 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
  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.
authors.affiliation: Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia.
authors.forename: Laurence G
authors.initials: LG
authors.lastname: Trahair
authors.forename: Michael
authors.initials: M
authors.lastname: Horowitz
authors.forename: Julie E
authors.initials: JE
authors.lastname: Stevens
authors.forename: Christine
authors.initials: C
authors.lastname: Feinle-Bisset
authors.forename: Scott
authors.initials: S
authors.lastname: Standfield
authors.forename: Diana
authors.initials: D
authors.lastname: Piscitelli
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Rayner
authors.forename: Adam M
authors.initials: AM
authors.lastname: Deane
authors.forename: Karen L
authors.initials: KL
authors.lastname: Jones
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology*; D005260:Female; D005746:Gastric Emptying / Q000187:drug effects* / Q000502:physiology; D052216:Glucagon-Like Peptide 1 / Q000494:pharmacology*; D005947:Glucose / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007328:Insulin / Q000097:blood; D008297:Male; D017538:Mesenteric Artery, Superior / Q000187:drug effects* / Q000503:physiopathology; D019518:Postprandial Period / Q000187:drug effects; D012039:Regional Blood Flow / Q000187:drug effects* / Q000502:physiology
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin; D052216:Glucagon-Like Peptide 1; D005947:Glucose