Evidence for the involvement of cAMP-dependent protein kinase in the exocytosis of amylase from parotid acinar cells.
To determine the role of cAMP-dependent protein kinase in the exocytosis of amylase from rat parotid acini, I studied the effects of various cAMP analogues on amylase release and protein phosphorylation in saponin-permeabilized parotid cells. The dose-dependent responses of amylase release and protein phosphorylation evoked by cAMP, dibutyryl-cAMP, and 8-chlorophenylthio-cAMP were closely correlated. Furthermore, when the permeabilized cells were incubated with a combination of site-selective cAMP analogues, such as N6-benzoyl-cAMP plus 8-thiomethyl-cAMP (RII-directed) or N6-benzoyl-cAMP plus 8-aminohexylamino-cAMP (RI-directed), synergistic stimulation of amylase release was clearly observed. As reported previously [T. Takuma (1988) Biochem. J. 256, 867-871], however, the protein phosphorylation evoked by 8-chlorophenylthio-cAMP was markedly inhibited by H-8 without a significant decrease in amylase release. These results suggest that cAMP-dependent protein kinase is involved in the regulation of amylase exocytosis, although the role of its catalytic subunit is still uncertain.
Department of Oral Biochemistry, School of Dentistry, Higashi Nippon Gakuen University, Hokkaido.
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D000681:Amylases / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D003994:Bucladesine / Q000494:pharmacology; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000494:pharmacology; D005089:Exocytosis / Q000502:physiology*; D066298:In Vitro Techniques; D007546:Isoquinolines / Q000494:pharmacology; D010306:Parotid Gland / Q000166:cytology* / Q000201:enzymology; D010766:Phosphorylation; D011494:Protein Kinases / Q000502:physiology*; D051381:Rats; D012503:Saponins / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology
D007546:Isoquinolines; D012503:Saponins; D013873:Thionucleotides; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D003994:Bucladesine; C053177:N-(2-(methylamino)ethyl)-5-isoquinolinesulfonamide; D000242:Cyclic AMP; D011494:Protein Kinases; D000681:Amylases