title: Hyaluronan-related limited concentration by the immature kidney.
abstract: The limited renal concentration performance by the immature kidney traditionally is thought to be attributed to blunted renal response to arginine vasopressin (AVP) and medullary hypotonicity. The diminished AVP-dependent osmotic water permeability of the collecting duct is the result of decreased AVP binding and adenylate cyclase activation, and low expression of aquaporin-2 (AQP2) mRNA and low levels of AQP2 protein. Moreover, the immature kidney fails to establish deep cortico-papillary osmotic gradient because of structural immaturity, limited solute transport and increased medullary blood flow. Based on indirect clinical and experimental evidences this article puts forward a hypothesis that during perinatal period the abundant hyaluronan (HA) content in the renomedullary interstitium has a primary role in antagonizing water reabsorption and limiting concentration performance. Hydration-related alterations in renal HA appears to be mediated by antidiuretic hormone. The concept of HA-mediated renal water transport may imply that interfering selectively with renal HA metabolism may provide a new therapeutic approach to promote diuresis or antidiuresis, respectively, according to the elevation or reduction in renomedullary HA.
authors.affiliation: Department of Health Promotion and Family Care, Faculty of Health Sciences, University of Pécs, Pécs, Hungary. esulyok.ppedhosp@axelero.hu
authors.forename: E
authors.initials: E
authors.lastname: Sulyok
authors.forename: Z
authors.initials: Z
authors.lastname: Nyúl
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001834:Body Water / Q000378:metabolism*; D019317:Evidence-Based Medicine; D006801:Humans; D006820:Hyaluronic Acid / Q000378:metabolism*; D007668:Kidney / Q000254:growth & development* / Q000378:metabolism*; D008954:Models, Biological; D014554:Urination / Q000502:physiology*; D014882:Water-Electrolyte Balance / Q000502:physiology*
chemical_list: D006820:Hyaluronic Acid