GIP antagonists were made in lean animals. Recently, Gault et al. reported that prolonged treatment of mice fed a high fat diet with a GIP antagonist improved glucose tolerance in these animals suggesting that reducing GIP signaling could be beneficial under these circumstances. In this reports Glucose tolerance was assessed after intraperitoneal glucose challenge which is not dependent upon GIP signaling and hence the improvement on glucose levels can be rather attributed to improved insulin signaling in this animals. Moreover McClean and colleagues investigated GIP antagonism in mice that had been fed a high fat diet Vaccination against Obesity for 160 days prior to the treatment with a GIP antagonist. Interestingly in these mice they found that a 50 day treatment with GIP led to weight loss, and significant improvement of glucose tolerance after both, i.p. challenge and feeding, suggesting that in severely obese mice antagonism of GIP is even beneficial for glucose homeostasis. Hence, removal of GIP signaling appears to affect glucose homeostasis differently depending on the nutritional state of the animals. Whereas GIPR2/2 animals show glucose intolerance on normal chow, the more recent work of McClean and colleagues show improvement of these parameters with their antagonists in severely obese mice after prolonged high fat feeding. Here these parameters were investigated in mice fed a high fat diet and most of our measurement were performed in between those two extreme situations. Hence, in view of these observations, the lack of notable effect on oral glucose tolerance in our experiments may not be that unexpected. Alternatively the differences observed here may be due to an incomplete neutralization of GIP by induced antibodies, still allowing for partial signaling to occur. Investigations of lipid metabolism revealed no changes in vLDL-, LDL- and HDL-cholesterol concentrations 
in the serum of Qb-GIP-vaccinated mice. Likewise, triglyceride and free fatty acid levels, as well as postprandial lipid clearance were not changed in vaccinated animals. Taken together, this study shows that active immunization against GIP leads to a strong reduction in body weight gain in mice 11335724 on a high fat diet and without deteriorating blood glucose or lipid homeostasis. Moreover in a preliminary experiment performed in obese male mice, suggests that active vaccination against GIP not only prevents excessive weight gain in animals fed a high fat diet but can also enhance weight loss in obese mice. The role of GIP in glucose and lipid metabolism is well documented in several animal species. Likewise, the incretin activity of GIP and GLP1 is well established in 24074843 humans. Based on these observations DPP-IV inhibitors have been developed and drugs like Sitagliptin and Vildagliptin are now on the Torin-1 market as a novel class of type II diabetes drugs. These antagonist, prevent the specific cleavage of the incretin hormones thereby increasing their half-lives and leading to increased insulin secretion. Interestingly, GIP has been reported to have a reduced incretin effect in type II diabetic patients whereas the insulinotropic effect of GLP is preserved in this patient population. These findings suggest on one hand that the major effect of DPP-IV antagonist is mediated by the stabilization of GLP1 and on the other hand that elimination of GIP should not have a major impact on glucose homeostasis in type II diabetic patients. However, whereas the incretin effect of G
