Receptors for natriuretic peptides in a human cortical collecting duct cell line.
The aim of the present study was to analyze the expression of natriuretic peptide receptors in human collecting duct, by using a newly established SV40 cell line (HCD). ANP and C-type natriuretic peptide (CNP) induced a concentration-dependent increase in cGMP suggesting the presence of type-A (NPR-A) and type-B (NPR-B) receptors, respectively. Threshold concentrations were 1 pM and 1 nM, respectively, and stimulated over basal cGMP ratios were 500 and 160 at 0.1 microM ANP and CNP. The urodilatin concentration-response curve was similar to that of ANP. [125I]-ANP bound specifically to HCD cells in a time-dependent fashion, reaching a plateau-phase between one and two hours at 4 degrees C. Equilibrium saturation binding curves suggested a single group of receptor sites (Kd = 421 +/- 55 pM, Bmax = 49.2 +/- 8.8 fmol/mg protein, Hill coefficient = 1.44 +/- 0.1, N = 6). Binding of [125I]-ANP was not displaced by CNP or by C-ANP (4-23), a specific ligand of clearance receptors (NPR-C), and thus occurred mainly via NPR-A. Neither Northern blot analysis nor RT-PCR could detect NPR-C mRNA, although the latter was clearly identified in control human glomerular visceral epithelial cells. In contrast, PCR products with the expected lengths were obtained for NPR-A and NPR-B. In conclusion, HCD cells express both NPR-A and NPR-B, as demonstrated by mRNA and cGMP production studies, but fail to produce NPR-C. This suggests that the human cortical collecting duct is a target for ANP, CNP and urodilatin.
Millul
V
V
INSERM U64, Hôpital Tenon, Paris, France.
Ardaillou
N
N
Placier
S
S
Baudouin
B
B
Ronco
P M
PM
D009320:Atrial Natriuretic Factor / Q000494:pharmacology; D001665:Binding Sites / Q000502:physiology; D001667:Binding, Competitive / Q000502:physiology; D015152:Blotting, Northern; D002461:Cell Line, Transformed / Q000737:chemistry / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D006801:Humans; D007457:Iodine Radioisotopes; D007672:Kidney Cortex / Q000166:cytology / Q000648:ultrastructure; D007685:Kidney Tubules, Collecting / Q000737:chemistry / Q000166:cytology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D017461:Receptors, Atrial Natriuretic Factor / Q000032:analysis* / Q000737:chemistry / Q000235:genetics*; D014158:Transcription, Genetic / Q000502:physiology
D007457:Iodine Radioisotopes; D012333:RNA, Messenger; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor; D006152:Cyclic GMP