title: Effects of stimulation of muscarinic and of beta-catecholamine receptors on the intracellular distribution of protein kinase C in guinea pig exocrine glands.
abstract: Stimulation of exocrine cells via muscarinic receptors is associated with an activation of protein kinase C [Padel & Söling (1985) Eur. J. Biochem. 151, 1-10]. We show here that stimulation of isolated parotid gland lobules with 8 X 10(-6) M-carbamoylcholine leads to a translocation of protein kinase C from the cytosolic to the particulate compartment within 30 s (25% and 45% of total activity recovered in the particulate fraction of controls and stimulated samples respectively). The specific enzyme activity in the particulate fraction increased to 169% of the corresponding control value. After 10 min the changes started to reverse and, after 30 min, cytosolic protein kinase C was higher in stimulated than in unstimulated lobules. Isoproterenol (2 X 10(-5) M) stimulated the release of amylase more than did carbamoylcholine, but did not significantly affect intracellular distribution of protein kinase C during the observation time of 30 min. In isolated pancreatic lobules a significant carbamoylcholine-mediated translocation of protein kinase C into the particulate fraction could be observed after 5 and 20 min, but not after 1 min. After 5 min the specific enzyme activity in the particulate fraction had increased to 153% of the corresponding controls. The corresponding decrease (-38%) in the specific enzymic activity of cytosolic protein kinase C stayed constant up to 30 min. In isolated parotid gland lobules alpha-amylase secretion proceeded at a linear rate already during the first 1 min of stimulation, whereas in pancreatic lobules a measurable rate of alpha-amylase secretion did not occur before 5 min. These differences in time course paralleled the differences in the onset of translocation of protein kinase C. The results support a direct involvement of protein kinase C in carbamoylcholine-mediated but not in isoproterenol-mediated stimulation of exocytosis in exocrine cells.
mesh_terms: D000818:Animals; D002217:Carbachol / Q000494:pharmacology*; D005088:Exocrine Glands / Q000201:enzymology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007424:Intracellular Fluid / Q000187:drug effects / Q000201:enzymology; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D010179:Pancreas / Q000187:drug effects / Q000201:enzymology; D010306:Parotid Gland / Q000187:drug effects / Q000201:enzymology; D011493:Protein Kinase C / Q000378:metabolism*; D011941:Receptors, Adrenergic / Q000187:drug effects / Q000378:metabolism*; D017983:Receptors, Catecholamine; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism*; D013268:Stimulation, Chemical
chemical_list: D011941:Receptors, Adrenergic; D017983:Receptors, Catecholamine; D011976:Receptors, Muscarinic; D002217:Carbachol; D011493:Protein Kinase C; D007545:Isoproterenol