title: Atrial natriuretic factor inhibits vasopressin-stimulated osmotic water permeability in rat inner medullary collecting duct.
abstract: The inner medullary collecting duct (IMCD) has been proposed to be a site of atrial natriuretic factor (ANF) action. We carried out experiments in isolated perfused terminal IMCDs to determine whether ANF (rat ANF 1-28) affects either osmotic water permeability (Pf) or urea permeability. In the presence of a submaximally stimulating concentration of vasopressin (10(-11) M), ANF (100 nM) significantly reduced Pf by an average of 46%. Lower concentrations of ANF also significantly inhibited vasopressin-stimulated Pf by the following percentages: 0.01 nM ANF, 18%; 0.1 nM, 46%; 1 nM, 48%. Addition of exogenous cyclic GMP (0.1 mM) mimicked the effect of ANF, decreasing Pf by an average of 48%. ANF also inhibited cyclic AMP-stimulated Pf by an average of 31%. ANF did not affect urea permeability, nor did it alter vasopressin-stimulated cyclic AMP accumulation. We conclude that ANF at physiological concentrations causes a large inhibition of vasopressin-stimulated Pf in the rat terminal IMCD, and that cyclic GMP is the second messenger mediating the effect. ANF appears to act at a site distal to cyclic AMP generation in the chain of events linking vasopressin receptor binding to an increase in osmotic water permeability.
authors.affiliation: Laboratory of Kidney and Electrolyte Metabolism, National Heart, Lung and Blood Institute, Bethesda, MD 20892.
authors.forename: H
authors.initials: H
authors.lastname: Nonoguchi
authors.forename: J M
authors.initials: JM
authors.lastname: Sands
authors.forename: M A
authors.initials: MA
authors.lastname: Knepper
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000187:drug effects*; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007679:Kidney Medulla / Q000378:metabolism; D007684:Kidney Tubules / Q000378:metabolism*; D007685:Kidney Tubules, Collecting / Q000378:metabolism*; D008297:Male; D009997:Osmotic Pressure; D051381:Rats; D011919:Rats, Inbred Strains; D014508:Urea / Q000378:metabolism; D014667:Vasopressins; D014882:Water-Electrolyte Balance / Q000187:drug effects*
chemical_list: C472610:atrial natriuretic peptide, rat; D014667:Vasopressins; C016276:8-bromocyclic GMP; D009320:Atrial Natriuretic Factor; D014508:Urea; D006152:Cyclic GMP