Dose‐dependent, and long‐lasting, effects of repeated intravenous injections of calcium on the canine secretin‐stimulated pancreatic juice secretion

Abstract

The effects of repeated i.v. Ca administration on pancreatic juice secretion were investigated in 4 Thomas fistula dogs. During stimulation by 1.0 U kg-1 h-1 GIH [gastrointestinal hormone] secretin, 3 Ca doses were administered: 2, 4 and 8 .mu.mol kg-1 min-1 during 1 h, saline being used in control tests; 1 dose only was tested per day. Ca administration induced both acute and long-lasting effects. Acute effects were characterized by an increased response to secretin stimulation. Fluid, HCO3-, protein and Ca outputs increased significantly in a dose-dependent manner, the increase of protein output being the most dramatic. Long-lasting effects were characterized by a progressive increase of protein secretion during the 1st hour of secretin stimulation. This increase kept going during the 3 mo. of repeated Ca injections. Although protein plugs were observed in the juice, sometimes stopping the flow of juice, no pancreatic lesion was found. A 2nd protocol showed that, after discontinuing Ca injections, the long-lasting effects decreased progressively, but protein hypersecretion was still significant 3.5 mo. later. The importance of these findings regarding chronic pancreatitis due to hyperparathyroidism is discussed.