A recent study on mice has revealed that gastric inhibitory polypeptide (GIP) receptor blockade is effective in promoting weight loss, improving insulin resistance and reversing diabetes.
GIP is a peptide hormone that is secreted in response to food. It inhibits the secretion of acids stimulates the releases insulin as part of the digestive process in response to food and plays a key role in metabolising fat.
The researchers examined the long-standing GIP receptor antagonism using daily injections of GIP receptor antagonist - (Pro3)GIP and whether it was able to overturn entrenched diet-induced obesity and linked metabolic abnormalities.
They used 8-week old male, age matched mice model that has close proximity with obesity found in humans who consume a high-fat, energy-rich diet, for diet-induced obesity
The mice were age-divided into groups and kept in an air-conditioned room individually where they had free access to drinking water and a high fat diet with 45 percent fat, 20 percent protein and 35 percent carbohydrate; percent of total energy of 26.15kj/g.
Age-matched mice from the same colony had free access to a standard rodent maintenance diet with 10 percent fat; 30 percent protein; 60 percent carbohydrate; percent of total energy of 12.99kj/g.
However, before the study, mice were been fed on a high fat diet for 160 days along with a separate set of mice been fed for 112 days. On both occasions, obesity and diabetes were clearly evident.
The mice fed on a high fat diet for 160 days received daily injections of either saline or (Pro3) GIP over a 50-day period.
The findings revealed that mice with standard rodent diet exhibited increased body weight, energy intake, and circulating glucose concentrations. The cholesterol and triglycerides levels also increased at day 50.
This led to weakened insulin sensitivity and glucose intolerance by 10 days. Fat (adipose) tissue deposits were increased as were circulating cholesterol and triglyceride concentration levels.
But (Pro3) GIP was able to counter many of the harmful effects of high fat diet on body weight and indices of glucose and lipid metabolism.
The study showed that blocking GIP activity using (Pro3)GIP in mice with established, high fat diet-induced obesity and diabetes resulted in significant weight loss, improvement of insulin resistance and amelioration of diabetes.
This discovery may harbour new approach for the treatment of obesity and metabolic disturbances, the authors said.
The findings appear in the American Journal of Physiology - Endocrinology and Metabolism.