Effect of Caerulein on Total and Ionized Calcium Secretion in the Duodenal Juice of Man

Abstract

Previous studies have demonstrated an increase of total calcium secretion in the duodenal juice of healthy subjects after cholecystokinin (CCK) administration superimposed on a continuous secretion infusion. In order to get more detailed information on the physiology of calcium secretion and its dependance on hormonal stimulation, ionized and total calcium were determined in the duodenal juice of 9 volunteers under constant stimulation with secretin and graded caerulein doses; bound calcium was calculated as the difference of total and ionized calcium. The results of total calcium were in good agreement with previously published data. We found that total calcium secretion is mainly determined by bound calcium and bound calcium is mainly secreted together with bile products. Since ionized calcium concentration was independent of caerulein administration it is suggested that its concentration in gallbladder bile must be in good accordance with that of hepatic bile and pancreatic juice together.