Maximum alkaline (bicarbonate) output of the dog pancreas

Abstract

By cannulation of the major pancreatic duct in six dogs with chronic Thomas type duodenal fistulas, dose-response curves have been obtained for the volume and bicarbonate output of pancreatic secretion stimulated by secretin (Vitrum). With single rapid intravenous injections (0.5–15 U/kg) or continuous intravenous infusions (1–16 U/min), increased doses of secretin produced increased volumes of pancreatic juice and bicarbonate outputs up to a maximum. This maximum alkaline output of the pancreas was reached at doses ranging from 7.5– 12.5 U/kg for single injections, and 4–16 U/min for infusions. In each dog supramaximum doses led to a fall in juice volume and bicarbonate output, unaccompanied by side effects. With supramaximum doses or intravenous infusions lasting longer than 30–90 min, bicarbonate concentration fell independently of juice volume. The chloride concentration consistently varied inversely with bicarbonate concentration. The sodium, potassium, and amylase concentrations were unaffected by rate of flow. Repeated measurements of basal secretion showed considerable variation. Coefficients of variation were low for repeated measurements of secretin-stimulated secretion, the most repeatable measurement being the maximum output of pancreatic juice in the first 15 min after a single injection which, in each of the six dogs, was almost identical to the plateau 15 min during infusion.