1. Glucagon-like peptide-1 (7-36) amide (GLP-1) is a gut hormone released postprandially that stimulates insulin secretion, suppresses glucagon secretion and delays gastric emptying. The insulinotropic action of GLP-1 is more potent under hyperglycaemic conditions. Several published studies have indicated the therapeutic potential of subcutaneous GLP-1 in non-insulin-dependent (Type 2) diabetes mellitus.
2. We investigated whether subcutaneous GLP-1, at a dose shown to improve glycaemic control in early Type 2 diabetes, is insulinotropic at normal fasting glucose concentrations. A double-blind, randomized, crossover study of 10 healthy subjects injected with GLP-1 or saline subcutaneously after a 16 h fast was performed. The effect on cardiovascular parameters was also examined.
3. GLP-1 caused a near 5-fold rise in plasma insulin concentration. After treatment with GLP-1, circulating plasma glucose concentrations fell below the normal range in all subjects. One subject had symptoms of hypoglycaemia after GLP-1. A rise in pulse rate was found which correlated with the fall in plasma glucose concentration. An increase in blood pressure occurred with GLP-1 injection which was seen at the same time as the rise in plasma GLP-1 concentrations.
4. This study indicates that subcutaneous GLP-1 can override the normal homoeostatic mechanism maintaining fasting plasma glucose in man, and is also associated with an increase in blood pressure.
Improved Glycemic Control With No Weight Increase in Patients With Type 2 Diabetes After Once-Daily Treatment With the Long-Acting Glucagon-Like Peptide 1 Analog Liraglutide (NN2211): A 12-week, double-blind, randomized, controlled trial
