GLIBENCLAMIDE PARTLY REVERSES MONENSIN INHIBITION OF INSULIN-SECRETION, IN-VIVO

Glibenclamide, a second generation sulfonylurea, is an oral hypoglycem ic drug. It seems to act mainly on the ATP-driven K+ -channels of the beta-cells of pancreas determining insulin secretion. Because monensin , a Na+/H+ antiport , is able when administered to rats in vivo to inh ibit insulin secretion, the action of glibenclamide is studied on glyc emia and insulinemia to verify if it can antagonize the action of mone nsin. The results show that glibenclamide is able to partly reverse io nophore induced hyperglycemia and the inhibition of insulin secretion. These results might be interpreted as if glibenclamide only reverses the ATP-driven K+- channel dependent insulin secretion. Moreover the a ntagonist action of glibenclamide is slightly delayed when both drugs are administered together. The role of Na+/H+ antiport in basal insuli n secretion is discussed.