title: Effect of retinoic acid on cellular content and human parathyroid hormone activation of cyclic adenosine 3':5'-monophosphate-dependent protein kinase isoenzymes in clonal rat osteogenic sarcoma cells.
abstract: Pretreatment with 10(-8) M retinoic acid for 4 days caused changes in three distinct components of the parathyroid hormone (PTH)-stimulated cyclic adenosine 3':5'-monophosphate response in a clonal rat osteogenic sarcoma cell line, UMR 106-06: the amplitude of the cyclic adenosine 3':5'-monophosphate response to PTH was moderately increased after pretreatment with retinoic acid; while the cellular content of the two isoenzymes of the cyclic adenosine 3':5'-monophosphate-dependent protein kinase was approximately equal in control cells, retinoic acid pretreatment was associated with a marked increase in the ratio of type II to type I holoenzyme activity. This change might be due to a decrease in the type I holoenzyme as suggested by immunofluorescence detection of decreased type I regulatory subunit in fixed cells together with the relative decrease in type I holoenzyme determined biochemically; there was a marked alteration of the pattern of PTH-stimulated protein kinase isoenzyme activation from predominantly type I isoenzyme in control cells to almost exclusively type II isoenzyme in retinoic acid-treated cells. Growth inhibition by submaximal amounts of PTH and retinoic acid when added together was greater than that for either agent alone.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000096:biosynthesis; D004789:Enzyme Activation; D006651:Histocytochemistry; D006801:Humans; D007527:Isoenzymes / Q000032:analysis*; D012516:Osteosarcoma / Q000201:enzymology* / Q000473:pathology; D010281:Parathyroid Hormone / Q000494:pharmacology*; D011494:Protein Kinases / Q000032:analysis*; D051381:Rats; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D007527:Isoenzymes; D010281:Parathyroid Hormone; D014212:Tretinoin; D000242:Cyclic AMP; D011494:Protein Kinases