title: Atrial natriuretic factor receptors in cultured renomedullary interstitial cells.
abstract: To gain further insight on the cell types that may mediate the effects of atrial natriuretic factor (ANF) in the renal medulla, we determined the distribution and function of biological (B) and clearance (C) receptors of ANF in renomedullary interstitial cells (RMIC). Studies were performed in the 3rd-17th passages of RMIC obtained from a primary culture of the rat renal medulla. Electron microscopy of the cultured cells showed the typical morphological features of RMIC "in vivo," including prominent lipid droplets. RMIC have a very high density of high-affinity specific binding sites of ANF-(1-28) [23,000 sites/cell; dissociation constant (Kd) = 50 pM]. There was only minimal binding of C-ANF-(4-23) (less than 2,500 sites/cell), a specific ligand of C-ANF receptors. ANF-(1-28) markedly increased guanosine 3',5'-cyclic monophosphate (cGMP) from 1.3 +/- 0.3 to 106 +/- 22 pmol cGMP/10(6) cells [50% effective dosage (ED50) = 1.2 nM]. The effect of ANF-(1-28) on cGMP was nearly additive to that of sodium nitroprusside and was not potentiated or antagonized by C-ANF-(4-23). The density of guanylate cyclase-coupled B-ANF receptors and the ANF-induced increase in cGMP in RMIC are higher than those reported to date in other target cells. This suggests that RMIC may mediate some of the known effects of ANF in the renal medulla.
authors.affiliation: Department of Physiology, Cornell University Medical College, New York, New York 10021.
authors.forename: B M
authors.initials: BM
authors.lastname: Fontoura
authors.forename: D R
authors.initials: DR
authors.lastname: Nussenzveig
authors.forename: K M
authors.initials: KM
authors.lastname: Pelton
authors.forename: T
authors.initials: T
authors.lastname: Maack
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D001667:Binding, Competitive; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D007679:Kidney Medulla / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D007700:Kinetics; D008297:Male; D008854:Microscopy, Electron; D051381:Rats; D011919:Rats, Inbred Strains; D017461:Receptors, Atrial Natriuretic Factor; D011956:Receptors, Cell Surface / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D011956:Receptors, Cell Surface; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor