title: Regulation of renal urea transport by vasopressin.
abstract: Terrestrial life would be miserable without the ability to concentrate urine. Production of concentrated urine requires complex interactions among the nephron segments and vasculature in the kidney medulla. In addition to water channels (aquaporins) and sodium transporters, urea transporters are critically important to the theories proposed to explain the physiologic processes occurring when urine is concentrated. Vasopressin (anti-diuretic hormone) is the key hormone regulating the production of concentrated urine. Vasopressin rapidly increases water and urea transport in the terminal inner medullary collecting duct (IMCD). Vasopressin rapidly increases urea permeability in the IMCD through increases in phosphorylation and apical plasma-membrane accumulation of the urea transporter A1 (UT-A1). Vasopressin acts through two cAMP-dependent signaling pathways in the IMCD: protein kinase A and exchange protein activated by cAMP Epac. Protein kinase A phosphorylates UT-A1 at serines 486 and 499. In summary, vasopressin regulates urea transport acutely by increasing UT-A1 phosphorylation and the apical plasma-membrane accumulation of UT-A1 through two cAMP-dependent pathways.
authors.affiliation: Emory University School of Medicine, Renal Division, 1639 Pierce Drive, NE, WMB Room 338, Atlanta, GA 30322, USA. jeff.sands@emory.edu
authors.forename: Jeff M
authors.initials: JM
authors.lastname: Sands
authors.forename: Mitsi A
authors.initials: MA
authors.lastname: Blount
authors.forename: Janet D
authors.initials: JD
authors.lastname: Klein
mesh_terms: D000818:Animals; D001692:Biological Transport; D002463:Cell Membrane Permeability; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D006801:Humans; D007671:Kidney Concentrating Ability; D007679:Kidney Medulla / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism; D010766:Phosphorylation; D015398:Signal Transduction; D014508:Urea / Q000378:metabolism*; D014667:Vasopressins / Q000378:metabolism*; D014867:Water / Q000378:metabolism
chemical_list: D020662:Guanine Nucleotide Exchange Factors; D026901:Membrane Transport Proteins; D014867:Water; D014667:Vasopressins; D014508:Urea; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases