title: Cyclic nucleotide phosphodiesterase isozymes in rat mesangial cells.
abstract: We characterized cyclic nucleotide phosphodiesterases isolated from rat mesangial cells and assessed their roles in regulating cellular cyclic nucleotide levels. Three peaks of phosphodiesterase activity were eluted by a linear sodium acetate gradient from a Q Sepharose column loaded with the mesangial cell extract. The first peak activity was stimulated by Ca(2+)-calmodulin and inhibited by calmodulin-stimulated phosphodiesterase inhibitors but not by a selective cGMP specific phosphodiesterase V inhibitor. The second, minor activity peak was stimulated by cyclic GMP and inhibited by EHNA [erythro-9-(2-hydroxy-3-nonyl)-adenine], a selective inhibitor of cyclic GMP-stimulated phosphodiesterase II. The last peak activity was not inhibited by cyclic GMP but selectively inhibited by rolipram [4-(3-cyclopentyloxy-4-methoxyphenyl)-2-pyrrolidene] or Ro 20-1724 [4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone], inhibitors of cyclic AMP specific, cyclic GMP insensitive phosphodiesterase IV. Based on their order of chromatographic elution, kinetic properties and sensitivity to allosteric agents and inhibitors, the peak 1, 2 and 3 correspond to phosphodiesterase I, II and IV. The basal cyclic GMP level was raised more effectively by selective inhibitor of phosphodiesterase I than phosphodiesterase II. In contrast, the atrial natriuretic factor-induced cyclic GMP elevation was potentiated more effectively by selective inhibitors of phosphodiesterase II than phosphodiesterase I. The forskolin-induced cyclic AMP increase was greatly potentiated by selective phosphodiesterase IV inhibitors but not by other phosphodiesterase inhibitors. These data suggest that phosphodiesterase I and II are responsible for cyclic GMP hydrolysis whereas phosphodiesterase IV is mainly responsible for cyclic AMP hydrolysis.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Schering-Plough Research Institute, Kenilworth, NJ 07033, USA.
authors.forename: H S
authors.initials: HS
authors.lastname: Ahn
authors.forename: M
authors.initials: M
authors.lastname: Foster
authors.forename: L
authors.initials: L
authors.lastname: Arik
authors.forename: G
authors.initials: G
authors.lastname: Boykow
authors.forename: C
authors.initials: C
authors.lastname: Foster
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002852:Chromatography, Ion Exchange / Q000379:methods; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D005920:Glomerular Mesangium / Q000201:enzymology*; D007527:Isoenzymes / Q000032:analysis* / Q000037:antagonists & inhibitors; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000032:analysis*; D051381:Rats
chemical_list: D007527:Isoenzymes; D010726:Phosphodiesterase Inhibitors; D000242:Cyclic AMP; D010727:Phosphoric Diester Hydrolases; D006152:Cyclic GMP