BACKGROUND
Dipeptidyl peptidase IV (DPP IV/CD26), a multi-functional glycoprotein, cleaves and inactivates major insulinotropic hormones, such as glucagon-like protein (GLP)-1 and glucose dependent insulinotrophic polypeptide (GIP). METHODS: The plasma DPP IV activities in ob/ob mice were measured at 4, 8 and 13 weeks of age and the correlation between the plasma glucose concentration and DPP IV activity analyzed at 7~9 weeks of age. The glucose lowering effects of P32/98, a DPP IV inhibitor, was assessed with the oral glucose tolerance test. RESULTS: The plasma DPP IV activities in ob/ob mice were higher than those in lean mice. The plasma DPP IV activity was correlated with the plasma glucose concentration both in male and female ob/ob mice. The glucose lowering effect of DPP IV inhibitor was more prominent in ob/ob than in lean mice. CONCLUSION: The plasma DPP IV activities in ob/ob mice were higher than in lean control mice, which may contribute to the higher glucose lowering effect of the DPP IV inhibitor in ob/ob mice