The effect of potassium, calcium and magnesium concentration on insulin and glucagon secretion of the perfused dog pancreas.

The effect of different potassium, calcium and magnesium concentrations in the perfusate on the hormone secretion of the isolated dog pancreas was investigated. A potassium concentration above 15 mMol/l shortly stimulates the insulin and glucagon secretion. Potassium ions (greater than or equal to 15 mMol/l) completely inhibit the early phase of glucose-induced insulin release. At a low Ca2+-level (0.25 mMol/l) the glucose-stimulated insulin secretion is reduced to basal values. On the other hand, the glucagon release is stimulated under these conditions. An increase of magnesium ions from 1.0 mMol/l to 2.5-7.5 mMol/l strikingly inhibits insulin and glucagon release by approximately 50%, which is compensated for insulin by increasing the Ca2+-content of the medium. Perfusates for normothermic pancreas perfusion should contain electrolyte concentrations within the physiological range.