Pancreatic acinar cells: use of Ca++ ionophore to separate enzyme release from the earlier steps in stimulus-secretion coupling

The Ca⁺⁺ ionophore A23187 had no effect on the release of amylase by mouse pancreas fragments in the absence of Ca⁺⁺ but when Ca⁺⁺ was re-added to the medium amylase release was observed in a pattern which mimicked that produced by normal stimulants. Uptake of ⁴⁵Ca⁺⁺ by pancreatic fragments was increased by A23187. Tetracaine and dinitrophenol at concentrations which block cholinergic stimulated enzyme release blocked ionophore induced release whereas atropine did not. None of the inhibitors studied affected the ionophore induced Ca⁺⁺ uptake.