title: Effect of ionomycin on cell pH in isolated renal proximal tubules.
abstract: In isolated rabbit proximal tubules the addition of 2.0 microM but not 0.2 microM ionomycin induced a sustained increase in cell pH ([pH]i). This [pH]i response to 2.0 microM ionomycin was shown to be independent of several transporters such as Na+/H+ exchanger, Na(+)-HCO3- cotransporter, Cl-/HCO3- exchanger, or H(+)-ATPase. On the other hand, the removal of extracellular Ca2+ abolished the [pH]i increase or even induced a transient [pH]i decrease in the presence of ionomycin. These results are consistent with the induction of Ca2+/H+ exchange by ionomycin. Therefore Ca2+ ionophores should be used with caution as probes to estimate renal tubule functions.
authors.affiliation: First Department of Internal Medicine, Tokyo University School of Medicine, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yamada
authors.forename: G
authors.initials: G
authors.lastname: Seki
authors.forename: S
authors.initials: S
authors.lastname: Taniguchi
authors.forename: S
authors.initials: S
authors.lastname: Uwatoko
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Kurokawa
mesh_terms: D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D005260:Female; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D015759:Ionomycin / Q000494:pharmacology*; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D006180:Proton-Translocating ATPases / Q000378:metabolism; D011817:Rabbits; D013997:Time Factors
chemical_list: D001639:Bicarbonates; D002352:Carrier Proteins; D015759:Ionomycin; D006180:Proton-Translocating ATPases; D002118:Calcium