Histamine stimulation of digestive enzyme secretion byin vitro rabbit pancreas

Abstract
Histamine (103 M) was found to stimulate pancreatic enzyme secretion fromin vitro isolated rabbit pancreas preparations. Histamine produced a peak and then a sustained stimulated secretory rate. Secretion of amylase, lipase, trypsinogen, chymotrypsinogen, and total radio active protein were all found to be stimulated. Although fluid output was slightly increased by histamine, enzyme concentrations in secretion were elevated. This, along with the observed sustained release rate, rules out washout effects. Histamine produced a significant response at 105 M with ED 50 being about 3×105 M and maximal responses produced by 103 M. Histamine stimulation can be blocked with mepyramine (104 or 105 M) or mepyramine in combination with cimetidine. The observed behavior of the pancreas suggests a similarity with pepsinogen secretion in the stomach.