Abstract
Secretory and vascular responses to various biogenic and foreign substances of the isolated blood-perfused canine pancreas were investigated. The majority of cholinergic drugs such as acetylcholine, methacholine, carbachol, bethanechol pilocarpine, neostigmine, lobeline, nicotine, TMA and McN-A-343, and gastrointestinal hormones such as secretin, pancreozymin, gastrin, glucagon caused an increase of output of pancreatic juice with vasodilatation. Bradykinin and kallikrein inhibited the secretion with vasodilatation, and DMPP, physostigmine and dopamine increased the secretion with vasoconstriction. Dibutyryl cyclic AMP, histamine, nitroglycerin and methylxanthines such as caffeine, theophylline and theobromine also caused a secretion with vasodilatation. Vasopressin inhibited the secretory rate of pancreatic juice with vasoconstriction. Most adrenergic drugs such as noradrenaline, adrenaline, phenylephrine, methoxamine, ephedrine, tyramine and isoprenaline except dopamine, had no effect on secretion. Vascular responses of the pancreas to various drugs were found to be similar to those of the mesenteric vessels. Since the secretion of pancreatic juice did not change in parallel with the rate of local blood flow, the mechanism of pancreatic secretion appears to be independent of the blood supply to the pancreas.
