Differential Inhibitory Effects of Serine/Threonine Phosphatase Inhibitors and a Calmodulin Antagonist on Phosphoinositol/Calcium- and Cyclic Adenosine Monophosphate-Mediated Pancreatic Amylase Secretion

Abstract

The inhibitory profiles of okadaic acid, calyculin A, cyclosporin A, and W-7 indicate that phosphatases 1 and 2A play a relevant role in cAMP-mediated enzyme release, whereas phosphatases 1 and 2B are predominantly involved in IP3/Ca(2+)-dependent stimulus-secretion coupling. The calmodulin antagonist W-7 interferes at multiple steps of intracellular signal-transduction pathways.