Effect of luminal calcium on proximal tubule bicarbonate reabsorption in the rat

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dc.contributor.authorGil, Frida Zaladek [UNIFESP]
dc.contributor.authorSilva, Vera Lidia Costa [UNIFESP]
dc.contributor.authorMalnic, Gerhard
dc.contributor.institutionUniversidade de São Paulo (USP)
dc.contributor.institutionUniversidade Federal de São Paulo (UNIFESP)
dc.date.accessioned2018-06-18T11:35:33Z
dc.date.available2018-06-18T11:35:33Z
dc.date.issued1995-11-01
dc.description.abstractIn previous investigations, it was found that rats depleted in parathyroid hormone (TPTX rats) had reduced rates of proximal bicarbonate reabsorption independent on blood calcium levels. In the present work, the role of calcium (Ca2+) in rat proximal tubule bicarbonate reabsorption was studied by in vivo stationary microperfusion. Tubules were perfused at different lumen Ca2- concentrations in the presence and absence of the calcium ionophore A23187. Bicarbonate reabsorption was not affected by Ca2+ in the range of 0 to 1 mM, but was significantly reduced when 0.5 mM EGTA was added to the 0 Ca2+ perfusates, indicating that only at very low luminal Ca2+ levels, bicarbonate reabsorption (= H+ secretion) was impaired. These observations indicate that Ca2+ in the tubule lumen is important for the maintenance of normal proximal bicarbonate transport, but the low Ca2+ level necessary to impair this transport mechanism is achieved only in the presence of EGTA, a condition that simulates the absence of parathyroid hormone.en
dc.description.affiliationUNIV SAO PAULO,DEPT PHYSIOL & BIOPHYS,INST CIENCIAS BIOMED,BR-05508 SAO PAULO,BRAZIL
dc.description.sourceWeb of Science
dc.format.extent271-277
dc.identifierhttp://dx.doi.org/10.1159/000173927
dc.identifier.citationRenal Physiology And Biochemistry. Basel: Karger, v. 18, n. 6, p. 271-277, 1995.
dc.identifier.doi10.1159/000173927
dc.identifier.issn1011-6524
dc.identifier.urihttp://repositorio.unifesp.br/handle/11600/45195
dc.identifier.wosWOS:A1995TZ66800001
dc.language.isoeng
dc.publisherKarger
dc.relation.ispartofRenal Physiology And Biochemistry
dc.rightsinfo:eu-repo/semantics/restrictedAccess
dc.rights.licensehttp://www.karger.com/Services/RightsPermissions
dc.subjectH+ secretionen
dc.subjectbicarbonate reabsorptionen
dc.subjectproximal tubuleen
dc.subjectcalciumen
dc.subjectcalcium ionophoreen
dc.titleEffect of luminal calcium on proximal tubule bicarbonate reabsorption in the raten
dc.typeinfo:eu-repo/semantics/article
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