Atrial natriuretic factor reduces cyclic adenosine monophosphate content of human fibroblasts by enhancing phosphodiesterase activity.
Radioligand binding studies disclosed one class of high affinity atrial natriuretic factor (ANF) receptors on human fibroblast membranes (Kd = 66 pM; maximum number of binding sites [Bmax] = 7,000 sites/cell). ANF increased cellular cyclic guanosine monophosphate (cGMP) content and suppressed isoproterenol- and PGE1-elevated, but not basal, cAMP content. Pertussis toxin pretreatment, which maximally ADP-ribosylated Gi, the guanine nucleotide-binding protein that couples inhibitory receptors to adenylate cyclase and blocks receptor-mediated inhibition of adenylate cyclase, did not interfere with ANF suppression of isoproterenol- or PGE1-elevated cellular cAMP content. Preliminary incubation of fibroblasts with 8-bromo cGMP or phosphodiesterase inhibitors, including 3-isobutyl-1-methylxanthine, Ro 20-1724, and cilostamide, however, prevented the ANF suppression of cAMP. MB 22948, an inhibitor that is partially selective for cGMP phosphodiesterase, did not block the effect of ANF. We conclude that in these cells, unlike other systems, ANF reduces cAMP content by activating a phosphodiesterase rather than by inhibiting adenylate cyclase.
Lee
M A
MA
Laboratory of Cellular Metabolism, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892.
West
R E
RE
Moss
J
J
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D037361:Adenylate Cyclase Toxin; D000527:Alprostadil / Q000494:pharmacology; D009320:Atrial Natriuretic Factor / Q000378:metabolism / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000201:enzymology / Q000378:metabolism*; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D037342:Pertussis Toxin; D011688:Purinones / Q000494:pharmacology; D011953:Receptors, Cyclic AMP / Q000032:analysis / Q000187:drug effects; D012867:Skin / Q000166:cytology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D037361:Adenylate Cyclase Toxin; C472955:NPPA protein, human; D011688:Purinones; D011953:Receptors, Cyclic AMP; D010566:Virulence Factors, Bordetella; D009320:Atrial Natriuretic Factor; D000242:Cyclic AMP; D037342:Pertussis Toxin; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D000527:Alprostadil; C011145:zaprinast; D007545:Isoproterenol; D015056:1-Methyl-3-isobutylxanthine