The GLP-1 system as a therapeutic target.

Glucagon-like peptide-1 (GLP-1) was first isolated and sequenced twenty years ago. It has been shown to have many effects in man. GLP-1 stimulates insulin secretion, delays gastric emptying, decreases glucagon levels and reduces appetite, all resulting in a fall in plasma glucose concentrations. More recently, evidence suggests it can stimulate beta cell neogenesis and improve cardiovascular function, and may even be neuroprotective. It is no surprise that this peptide is of increasing interest as a target for the treatment of diabetes. None of the drugs currently available for diabetes are able to achieve targets in all patients and none of them are without side effects. The multiple modes of action of GLP-1 together with its low propensity for hypoglycaemia appear to give it advantages over currently available treatment modalities. In this review I shall examine the data suggesting that medications modelled on the GLP-1 system may provide a new therapeutic option for diabetes in the future.