title: Selective regulation of the amount of catalytic subunit of cyclic AMP-dependent protein kinases during isoprenaline-induced growth of the rat parotid gland.
abstract: Stimulation of growth of the rat parotid gland by repeated injection of the beta-agonist isoprenaline led to a significant decrease in the activity of cyclic AMP-dependent protein kinases. Immunochemical quantification of the catalytic (C) and regulatory (RI and RII) subunits of the cyclic AMP-dependent protein kinases type I and type II revealed a loss of 65% of the immunochemically measurable amount of catalytic subunit C. The amount of the regulatory subunits, however, remained constant. The observed decrease in C-subunit was not due to a translocation of the molecule to cellular membranes or to an inhibiting effect of the heat-stable inhibitor of cyclic AMP-dependent protein kinases. A selective decrease in only the C-subunit was also observed after a brief exposure to isoprenaline leading to the stimulation of DNA synthesis. Under these conditions, the decrease was observed at the onset of DNA synthesis (17 h after injection), but not at the the time of an earlier small cyclic AMP peak (13 h after injection) or at the time of maximal DNA synthesis (24 h after injection). The results indicate that the amount of the catalytic subunit of cyclic AMP-dependent protein kinases can be regulated independently from that of the regulatory subunits. The time-limited occurrence of the specific change in the amount of the C-subunit suggests that such a regulation is of physiological significance and that it may participate in cyclic AMP-mediated events involved in the control of cellular proliferation.
authors.affiliation: Abteilung für Klinische Biochemie, Universitätskliniken Göttingen, Federal Republic of Germany.
authors.forename: G
authors.initials: G
authors.lastname: Schwoch
mesh_terms: D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D007122:Immunoelectrophoresis; D007527:Isoenzymes / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010306:Parotid Gland / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D011494:Protein Kinases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D007527:Isoenzymes; D011506:Proteins; D004247:DNA; D000242:Cyclic AMP; D011494:Protein Kinases; D007545:Isoproterenol