title: Transepithelial sulfate transport by avian renal proximal tubule epithelium in primary culture.
abstract: The mechanisms and control of transepithelial inorganic sulfate (Si) transport by primary cultures of chick renal proximal tubule monolayers in Ussing chambers were determined. The competitive anion, S2 O 3 2- (5 mM), reduced both unidirectional reabsorptive and secretory fluxes and net Si reabsorption with no effect on electrophysiological properties. The carbonic anhydrase (CA) inhibitor ethoxzolamide decreased net Si reabsorption approximately 45%. CAII protein and activity were detected in isolated chick proximal tubules by immunoblots and biochemical assay, respectively. Cortisol reduced net Si reabsorption up to approximately 50% in a concentration-dependent manner. Thyroid hormone increased net Si reabsorption threefold in 24 h, and parathyroid hormone (PTH) acutely stimulated net Si reabsorption approximately 45%. These data indicate that CA participates in avian proximal tubule active transepithelial Si reabsorption, which cortisol directly inhibits and T3 and PTH directly stimulate.
authors.affiliation: Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269, USA.
authors.forename: Paul L
authors.initials: PL
authors.lastname: Dudas
authors.forename: J Larry
authors.initials: JL
authors.lastname: Renfro
mesh_terms: D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002645:Chickens; D004591:Electrophoresis, Polyacrylamide Gel; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism*; D006854:Hydrocortisone / Q000494:pharmacology; D015151:Immunoblotting; D066298:In Vitro Techniques; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000494:pharmacology; D013431:Sulfates / Q000378:metabolism*; D013997:Time Factors; D014284:Triiodothyronine / Q000494:pharmacology
chemical_list: D010281:Parathyroid Hormone; D013431:Sulfates; D014284:Triiodothyronine; D006854:Hydrocortisone