LEP and cholelithiasis: To evaluate the differences in leptin and insulin concentrations in the cholelithiasis patients with or without DM, the members of the cholelithiasis group were separated into dogs with DM and without it, and we showed that the concurrence of DM with cholelithiasis did not significantly affect serum leptin and insulin levels (p = 0.717 and p = 0.089, respectively; Fig 3).