Amongst other things, eating a meal rich in fat triggers the release of GIP from the duodenum in the intestine.
Yutaka Seino and colleagues, from Kyoto University, Japan, bred mice that lack the receptor for GIP.
When these mice were fed a high-fat diet, they failed to gain weight. They also did not suffer from insulin resistance, another condition that links obesity with diabetes.
| Fat is not accumulated in the absence of GIP receptor.
Seino's team also showed that, mice lacking the GIP receptor and the gene for another hormone, called leptin, were even skinnier than mice lacking the GIP receptor alone.
It appears that, in the absence of the GIP receptor, fat is not accumulated in fat cells, but is used as the primary energy source.
Thus, GIP directly links over-eating to obesity and is a potential target for anti-obesity drugs.