title: 1,25 Dihydroxyvitamin D causes attenuation of cyclic AMP responses in monocyte-like cells.
abstract: The U937 cell is a human monocyte-like line which possesses 1,25(OH)2D receptors. To study 1,25(OH)2D actions in these cells we have measured the cAMP produced by U937 cells during 10 minute stimulus by the beta-adrenergic agonist isoproterenol or by forskolin. cAMP produced by isoproterenol is 6 times that of forskolin. When cells are exposed to 1,25(OH)2D for at least 8 hours the cAMP produced is decreased up to 55%. This attenuative effect of 1,25(OH)2D is dose dependent with an EC50 of 10(-10)M. Other vitamin D metabolites are less than 1/100th as potent.
mesh_terms: D002117:Calcitriol / Q000494:pharmacology*; D002316:Cardiotonic Agents / Q000494:pharmacology; D002460:Cell Line; D005576:Colforsin; D000242:Cyclic AMP / Q000378:metabolism*; D004224:Diterpenes / Q000494:pharmacology; D006801:Humans; D006887:Hydroxycholecalciferols / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D007700:Kinetics; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism*
chemical_list: D002316:Cardiotonic Agents; D004224:Diterpenes; D006887:Hydroxycholecalciferols; D005576:Colforsin; D000242:Cyclic AMP; D002117:Calcitriol; D007545:Isoproterenol