title: Effects of calyculin A on amylase release in streptolysin-O permeabilized acinar cells.
abstract: The effects of the phosphatase inhibitors calyculin A and okadaic acid on amylase release from streptolysin-O permeabilized rat pancreatic acini were investigated. Both agents induced similar biphasic effects with moderate potentiation of calcium-stimulated amylase release at medium and strong inhibition at higher concentrations. Calyculin A was thirty times more potent than okadaic acid and at 100 nM totally inhibited calcium-induced amylase release while 3 microM okadaic acid reduced amylase release by 78%. 100nM calyculin A also completely inhibited GTP gamma S-potentiated amylase release and partially inhibited phorbol ester potentiated secretion. The data indicate that inhibition of a serine/threonine phosphatase, probably a type 1 phosphatase, leads to inhibition of calcium-induced amylase release in permeabilized pancreatic acini.
mesh_terms: D000681:Amylases / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins; D002118:Calcium / Q000494:pharmacology; D002273:Carcinogens / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004988:Ethers, Cyclic / Q000494:pharmacology; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008387:Marine Toxins; D019319:Okadaic Acid; D010080:Oxazoles / Q000494:pharmacology*; D010179:Pancreas / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013301:Streptolysins / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D002273:Carcinogens; D004988:Ethers, Cyclic; D008387:Marine Toxins; D010080:Oxazoles; D013301:Streptolysins; C025964:streptolysin O; D019319:Okadaic Acid; D016244:Guanosine 5'-O-(3-Thiotriphosphate); C059041:calyculin A; D000681:Amylases; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium