Amylase secretion from saponin-permeabilized parotid cells evoked by cyclic AMP.
Adenosine 3',5'-monophosphate (cAMP) evoked amylase release from saponin-permeabilized parotid cells of the rat. Saponin concentration was optimal at 10 micrograms/ml. Amylase release was stimulated by cAMP almost as well in Ca2+-free medium containing 1 mM EGTA as in the medium containing a physiological concentration of calcium. Although the basal and stimulated releases of amylase were markedly reduced by the further addition of 5 mM EGTA, the effect of cAMP was still detectable. The half-maximal dose of cAMP was 0.3 mM, whereas those of dibutyryl cAMP and 8-bromo-cAMP were 10-fold lower than that of cAMP. In the presence of 10 microM 3-isobutyl-1-methylxanthine, the half-maximal dose of cAMP was also decreased by 5-fold. These results suggest: 1) intracellular calcium is not essential for the exocytosis of amylase stimulated by cAMP; 2) the responsiveness of the cells to exogenous cAMP is reduced by phosphodiesterase.
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000681:Amylases / Q000378:metabolism*; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002463:Cell Membrane Permeability; D000242:Cyclic AMP / Q000494:pharmacology*; D004533:Egtazic Acid / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D010306:Parotid Gland / Q000187:drug effects / Q000201:enzymology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D012503:Saponins / Q000494:pharmacology*
D012503:Saponins; D015124:8-Bromo Cyclic Adenosine Monophosphate; D004533:Egtazic Acid; D003994:Bucladesine; D000242:Cyclic AMP; D000681:Amylases; D011188:Potassium; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine