Effect of insulin on small intestinal transit in normal mice is independent of blood glucose level

BACKGROUND: Insulin is the drug of choice in the management of diabetes mellitus (DM). About 76 % of diabetic patients suffer from gastrointestinal (GI) disorders. Therapy of DM with insulin primarily involves lowering of elevated blood glucose levels. Hence, on any organ in addition to insulin's effect, hypoglycaemic effect also prevails. A systematic study exploring the effect of insulin on small intestinal transit in normal laboratory animals is lacking. Hence, in the present study, the possible effect of insulin with or without associated hypoglycaemia on small intestinal transit in normal mice was examined. RESULTS: Insulin in all the doses tested (2 μ, 2 m and 2 U/kg) elicited a significant acceleration of SIT. The lower doses of insulin (2 μ and 2 m U/kg) produced significant acceleration of SIT and were associated with normal blood glucose levels. However, the highest dose of insulin (2 U/kg) produced an acceleration of SIT that was associated with significant fall in blood glucose levels. Further, the 2 m and 2 U doses of insulin significantly elevated serum insulin and C-peptide levels. CONCLUSION: Insulin at the lowest dose produced an acceleratory effect on SIT that was independent of blood glucose and serum insulin levels in normal mice.