Sialagogue-stimulated protein phosphorylation related to ornithine decarboxylase induction in cultured rat parotid explants.
Both beta-adrenergic (isoproterenol) and cholinergic (carbachol) sialagogues increase amylase secretion, ornithine decarboxylase activity and DNA synthesis in murine parotid gland in vivo and in vitro. These agonists enhanced the incorporation of labelled inorganic orthophosphate into parotid proteins in rat parotid explants cultured on siliconized lens paper floating on serum-free 199 medium. Analysis of the labelled proteins by SDS-PAGE and autoradiography revealed that isoproterenol enhanced the phosphorylation of four proteins with apparent molecular weights of 17, 20, 31 and 32 kDa and carbachol stimulated the phosphorylation of 31 and 32 K proteins. Isoproterenol-dependent ornithine decarboxylase induction and phosphorylation of the proteins were selectively suppressed by monensin but not by polymyxin B, whereas carbachol-dependent ornithine decarboxylase induction and protein phosphorylation were inhibited by polymyxin B but not by monensin. Neither monensin nor polymyxin B suppressed isoproterenol- or carbachol-stimulated amylase secretion. Time course experiments showed that sialagogue-stimulated protein phosphorylation preceded the increase of ornithine decarboxylase activity and had almost disappeared when it was maximal. Propranolol and atropine, antagonists of isoproterenol and carbachol, respectively, completely inhibited not only amylase secretion and ornithine decarboxylase induction but also protein phosphorylation stimulated by the corresponding agonists. These findings suggest that increased phosphorylation of specific proteins is associated with sialagogue-stimulated ornithine decarboxylase induction but not amylase secretion.
Ueno
A
A
Department of Biochemistry, School of Dentistry, University of Tokushima, Japan.
Kikuchi
K
K
Nishino
M
M
Kawano
M
M
Matsumoto
N
N
Inoue
H
H
D000681:Amylases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology*; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D008970:Molecular Weight; D008985:Monensin / Q000494:pharmacology; D009924:Organ Culture Techniques; D009955:Ornithine Decarboxylase / Q000096:biosynthesis*; D065108:Ornithine Decarboxylase Inhibitors; D010306:Parotid Gland / Q000201:enzymology / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation / Q000187:drug effects; D011112:Polymyxin B / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012471:Salivary Proteins and Peptides / Q000378:metabolism*
D065108:Ornithine Decarboxylase Inhibitors; D010710:Phosphates; D010761:Phosphorus Radioisotopes; D012471:Salivary Proteins and Peptides; D001285:Atropine; D002217:Carbachol; D008985:Monensin; D011433:Propranolol; D011494:Protein Kinases; D011493:Protein Kinase C; D000681:Amylases; D009955:Ornithine Decarboxylase; D011112:Polymyxin B; D007545:Isoproterenol