Glucose-dependent insulinotropic polypeptide (GIP): anti-diabetic and anti-obesity potential?

Glucose-dependent insulinotropic polypeptide (GIP or gastric inhibitory polypeptide) is a gastrointestinal hormone, which modulates physiological insulin secretion. Due to its insulinotropic activity, there has been a considerable increase of interest in utilising the hormone as a potential therapy for type 2 diabetes. One of the difficulties in attempting to harness the insulinotropic activity of GIP into an effective therapeutic agent is its short biological half-life in the circulation. However, recent years have witnessed the development of a substantial number of designer enzyme-resistant 'super GIP' molecules with potent insulinotropic and anti-diabetic properties. In addition, observations in transgenic GIP receptor deficient mice indicate that GIP directly links overnutrition to obesity, therein playing a crucial role in the development of obesity and related metabolic disorders. The present review aims to highlight the rapidly emerging potential therapeutic applications of GIP, and especially, enzyme-resistant GIP analogues.