Background: Both diabetes and obesity are associated with an increased risk of cholesterol gallstones. However, the relative importance of these two risk factors is difficult to determine as obesity and diabetes are strongly associated. Previous studies from this laboratory with leptin-deficient (Lep^ob) and leptin-resistant (Lep^db) obese mice have demonstrated decreased gallbladder motility that correlates with increasing body weight as well as serum glucose and insulin levels. However, the relative role of diabetes, obesity, or an abnormal leptin pathway in biliary motility remains unclear. Therefore, we tested the hypothesis that leptin-normal, non-obese diabetic (NOD) mice would have reduced gallbladder motility. Methods: Eight-week old lean control (C57BL/6J, n=10) and NOD (n=10) mice were fed a non-lithogenic chow diet for four weeks. All animals were fasted overnight and underwent cholecystectomies. Bile was aspirated from the intact gallbladder, and the volume (μl) was recorded. Contractile response (N/cm²) to acetylcholine (Ach 10^-5M), neuropeptide Y (NPY 10^-8,-7,-6M), and cholecystokinin (CCK 10^-10,-9,-8,-7M) was measured. Results were analyzed using the Mann-Whitney Rank Sum Test and are displayed in the table. Conclusions: These data suggest that leptin-normal, non-obese diabetic mice have 1) similar gallbladder volume but 2) diminished response to acetylcholine, neuropeptide Y, and cholecystokinin compared to the lean control mice. Therefore, we conclude that diabetes, in the absence of obesity or altered leptin function, is associated with abnormal biliary motility. Thus, diabetes may provide a link between obesity, altered biliary motility, and gallstone formation.