title: PMA and ionomycin differently affect atrial natriuretic peptide stimulated cyclic GMP production in rat mesangial cells.
abstract: How 4 beta-phorbol 12-myristate 13-acetate (PMA) and ionomycin (Io), a calcium ionophore, affect on the atrial natriuretic peptide (ANP) stimulated cyclic-3',5'-guanosine monophosphate (cGMP) production in cultured rat mesangial cells was examined. Cultured mesangial cells were prepared by isolated glomeruli from Sprague Dawley rats employing the sieving method and were used between the 3rd and 15th passage for experiments. cGMP and protein contents were measured by radioimmunoassay and Lowry method. Incubations with effectors were carried out either in the presence or absence of 0.5 mM 1-methyl-3-isobutyl-xanthine (MIX). The intracellular concentration of calcium ([Ca2+]i) was determined by using the Fura-2 method. Pretreatment with PMA, an activator of protein kinase C (PKC), attenuated ANP stimulated cGMP production in a time- and dose-dependent fashion, while alpha PDD (an inactive analog of PMA) did not inhibit cGMP production. PMA inhibition was reversed by addition of staurosporine, a protein kinase C inhibitor. Io attenuated ANP stimulated cGMP production in the absence but not in the presence of MIX. These findings suggested that PMA acts on ANP receptor or guanylate cyclase via activation of PKC in rat mesangial cells. Io may inhibit ANP stimulated cGMP production via activation of cyclic nucleotide phosphodiesterase.
authors.affiliation: Department of Medicine, Jichi Medical School, Tochigi, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Akai
authors.forename: E
authors.initials: E
authors.lastname: Kusano
authors.forename: M
authors.initials: M
authors.lastname: Amemiya
authors.forename: S
authors.initials: S
authors.lastname: Ono
authors.forename: S
authors.initials: S
authors.lastname: Takeda
authors.forename: S
authors.initials: S
authors.lastname: Homma
authors.forename: Y
authors.initials: Y
authors.lastname: Asano
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D006152:Cyclic GMP / Q000096:biosynthesis*; D004789:Enzyme Activation / Q000187:drug effects; D005920:Glomerular Mesangium / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015759:Ionomycin / Q000494:pharmacology*; D007476:Ionophores / Q000494:pharmacology*; D008297:Male; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
chemical_list: D007476:Ionophores; D010726:Phosphodiesterase Inhibitors; D015759:Ionomycin; D009320:Atrial Natriuretic Factor; D011493:Protein Kinase C; D006152:Cyclic GMP; D013755:Tetradecanoylphorbol Acetate; D015056:1-Methyl-3-isobutylxanthine