Glucocorticoids stimulate rabbit proximal convoluted tubule acidification

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Abstract

Glucocorticoids have an important role in renal acidification; however, a direct effect of glucocorticoids on proximal convoluted tubule (PCT) acidification has not been directly demonstrated. In the present in vitro microperfusion study PCT from animals receiving dexamethasone (600 μg/kg twice daily for 2 d and 2 h before killing) had a significantly higher rate of bicarbonate absorption than did controls (92.0±13.3 vs 59.9±3.2 pmol/mm · min, P < 0.01). To examine if glucocorticoids had a direct epithelial action, dexamethasone was added to the bath of PCT perfused in vitro. After 3 h of incubation in paired experiments 10-6 M and 10-5 M dexamethasone resulted in an ~ 30% stimulation in the rate of bicarbonate absorption. 10- 7 M dexamethasone and 10-6 M aldosterone had no effect on bicarbonate absorption. The stimulation of acidification by 10-5 M dexamethasone was blocked by actinomycin D and cycloheximide. These data are consistent with a direct effect of glucocorticoids on PCT acidification, and this effect is dependent upon protein synthesis.

Original languageEnglish (US)
Pages (from-to)110-114
Number of pages5
JournalJournal of Clinical Investigation
Volume91
Issue number1
DOIs
StatePublished - Jan 1 1993

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Keywords

  • acidification
  • glucocorticoids
  • microperfusion
  • proximal tubule
  • volume absorption

ASJC Scopus subject areas

  • Medicine(all)

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