Phorbol and calcium decreased atriopeptin response in a human renal cell line.
We investigated regulation of atrial natriuretic factor (ANF)-stimulated cellular cGMP accumulation (ANF-s-cGMP) in an ANF-responsive human renal cell line, SK-NEP-1. Dose-response data indicated that the EC50 for ANF(99-126) was 1.1 x 10(-9) M. Brain natriuretic peptide (10(-6) M) increased cGMP to a level indistinguishable from that of ANF (10(-6) M). [Met-(O)]ANF was only half as potent as ANF, and atriopeptin I (10(-6) M) did not increase cGMP over basal levels. Preincubation of SK-NEP-1 cells with ANF, but not atriopeptin I (API), for two hours or longer, caused a concentration-dependent down-regulation of ANF-s-cGMP. Phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, and A23187 and its 4-bromo derivative, calcium ionophores, inhibited ANF-s-cGMP in a dose-dependent manner. A23187 inhibition was calcium dependent and promoted net cGMP degradation. Thirty-six hour preincubation with PMA, a procedure used to down-regulate PKC, abolished acute PMA inhibition of ANF-s-cGMP without having an effect on ANF-s-cGMP or on 4-bromo-A23187 inhibition thereof. These data indicate that PKC activation specifically inhibited ANF-s-cGMP but that PKC was not required for ANF-s-cGMP in SK-NEP-1 cells. Thus structurally related ANF peptides, protein kinase C (PKC) activators, calcium ionophores are potential modulators of ANF-s-cGMP in cells from this human renal cell line.
Iwata
T
T
Alton Ochsner Medical Foundation, New Orleans, LA 70121.
Vaughn
J
J
Frohlich
E D
ED
Cole
F E
FE
D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D006152:Cyclic GMP / Q000096:biosynthesis*; D006801:Humans; D011493:Protein Kinase C / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
D000001:Calcimycin; D009320:Atrial Natriuretic Factor; D011493:Protein Kinase C; D006152:Cyclic GMP; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium