Glucagon-like peptide 1 abolishes the postprandial rise in triglyceride concentrations and lowers levels of non-esterified fatty acids in humans.
OBJECTIVE
Diabetic dyslipidaemia contributes to the excess morbidity and mortality in patients with type 2 diabetes. Exogenous glucagon-like peptide 1 (GLP-1) lowers postprandial glycaemia predominantly by slowing gastric emptying. Therefore, the effects of GLP-1 on postprandial lipid levels and gastric emptying were assessed.


METHODS
14 healthy male volunteers were studied with an i.v. infusion of GLP-1 (1.2 pmol kg(-1) min(-1)) or placebo over 390 min in the fasting state. A solid test meal was served and gastric emptying was determined using a (13)C-labelled sodium octanoate breath test. Venous blood was drawn frequently for measurement of glucose, insulin, C-peptide, glucagon, GLP-1, triglycerides and NEFA.


RESULTS
GLP-1 administration lowered fasting and postprandial glycaemia (p<0.0001). Gastric emptying was delayed by GLP-1 compared with placebo (p<0.0001). During GLP-1 administration, insulin secretory responses were higher in the fasting state but lower after meal ingestion. After meal ingestion, triglyceride plasma levels increased by 0.33+/-0.14 mmol/l in the placebo experiments (p<0.0001). In contrast, the postprandial increase in triglyceride levels was completely abolished by GLP-1 (change in triglycerides, -0.023+/-0.045 mmol/l; p<0.05). During GLP-1 infusion, plasma concentrations of NEFA were suppressed by 39% in the fasting state (p<0.01) and by 31+/-5% after meal ingestion (p<0.01).


CONCLUSIONS
GLP-1 improves postprandial lipidaemia, presumably as a result of delayed gastric emptying and insulin-mediated inhibition of lipolysis. Thus, by lowering both glucose and lipid concentrations, GLP-1 administration may reduce the cardiovascular risk in patients with type 2 diabetes.
Meier
J J
JJ
Department of Medicine I, St Josef Hospital, Ruhr University, Bochum, Germany. jmeier@mednet.ucla.edu
Gethmann
A
A
Götze
O
O
Gallwitz
B
B
Holst
J J
JJ
Schmidt
W E
WE
Nauck
M A
MA
D000328:Adult; D004032:Diet; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005934:Glucagon / Q000097:blood; D052216:Glucagon-Like Peptide 1 / Q000494:pharmacology*; D006801:Humans; D008297:Male; D019518:Postprandial Period / Q000187:drug effects* / Q000502:physiology; D013270:Stomach / Q000187:drug effects; D014280:Triglycerides / Q000097:blood*
D005230:Fatty Acids, Nonesterified; D014280:Triglycerides; D052216:Glucagon-Like Peptide 1; D005934:Glucagon