title: Separate control of regulatory volume increase and Na+-H+ exchange by cultured renal cells.
abstract: Suspensions of OK cells (a continuous epithelioid cell line from opossum kidney) are examined by electronic cell sizing, measurements of intracellular pH, and measurements of cellular Na+ and K+. The response of the cells to hypertonic solutions is evaluated in most detail. When shrunken by exposure to hyperosmotic medium (430 mosmol/kg), the cells do not demonstrate a regulatory volume increase (RVI) independent of the solute that is used to increase osmolality [NaCl, N-methyl-D-glucamine-HCl (NMGCl), or sucrose]. In contrast, when cells are preexposed to 190 mosmol/kg medium and then shrunken by exposure to 310 mosmol/kg medium, a volume increase is observed after the addition of 120 mosmol/kg NaCl or NMGCl, but not sucrose. This RVI is sensitive to 1 mM furosemide and removal of Na+ or K+ from the medium, but it is not inhibited by 1 mM amiloride. In the presence of a propionate-induced cellular acidification, a Na+-H+ exchanger in the cells is shown to have a large capacity for net solute uptake and to be inhibited by 1 mM amiloride. Net solute uptake by the Na+-H+ exchanger is sensitive to addition of parathyroid hormone or 8-bromoadenosine 3',5'-cyclic monophosphate but is not stimulated in response to cell shrinkage.
authors.affiliation: Institute of Physiology, University of Zurich, Switzerland.
authors.forename: M H
authors.initials: MH
authors.lastname: Montrose
authors.forename: C
authors.initials: C
authors.lastname: Knoblauch
authors.forename: H
authors.initials: H
authors.lastname: Murer
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D005665:Furosemide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000378:metabolism*; D008536:Meglumine / Q000494:pharmacology; D009893:Opossums; D009994:Osmolar Concentration; D010281:Parathyroid Hormone / Q000494:pharmacology; D011422:Propionates / Q000494:pharmacology; D017923:Sodium-Hydrogen Exchangers
chemical_list: D002352:Carrier Proteins; D010281:Parathyroid Hormone; D011422:Propionates; D017923:Sodium-Hydrogen Exchangers; D015124:8-Bromo Cyclic Adenosine Monophosphate; D008536:Meglumine; D000584:Amiloride; D005665:Furosemide; C029658:propionic acid