Evidence against a direct role for protein kinase C in rat submandibular salivary mucin secretion.
Calcium and protein kinase C may be directly involved in exocytosis. However, in the rat submandibular gland, cAMP-mediated events appear to be required for mucin secretion. Calcium may be involved, but a direct signal-transduction role for calcium and protein kinase C in regulating such secretion has yet to be established. With dispersed rat submandibular acinar-intercalated duct complexes, endogenous protein phosphorylation and mucin secretion studies were performed to determine if 12-O-tetradecanoylphorbol 13-acetate (PMA), a specific activator of protein kinase C, could act as an effective secretagogue for mucin secretion and if specific protein phosphorylation could be assigned to protein kinase C activation. PMA did not elicit such phosphorylation and it only slightly increased mucin secretion at high concentrations; these slight increases appeared to be non-specific. Therefore, protein kinase C activation may not be directly involved in regulating rat submandibular mucin secretion.
Quissell
D O
DO
Oral Sciences Research Center, University of Colorado Health Sciences Center, Aurora 80012.
Barzen
K A
KA
Deisher
L M
LM
D000818:Animals; D004789:Enzyme Activation; D008297:Male; D009077:Mucins / Q000378:metabolism*; D011493:Protein Kinase C / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012463:Saliva / Q000378:metabolism*; D013363:Submandibular Gland / Q000187:drug effects / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D009077:Mucins; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate