Acute increases of renal medullary osmolality stimulate endothelin release from the kidney

Erika I. Boesen, David M. Pollock

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Experiments conducted in vitro suggest that high osmolality stimulates endothelin production and release by renal tubular epithelial cells. Whether hyperosmotic solutions exert similar effects in vivo is unknown. Therefore, we tested the hypothesis that increasing renal medullary osmolality enhances urinary excretion of endothelin in anesthetized rats. Isosmotic NaCl (284 mosmol/kgH2O) was infused either intravenously (1.5 ml/h) or into the renal medullary interstitium (0.5 ml/h) during a 1-h equilibration period and 30-min baseline urine collection period, followed by either isosmotic or hyperosmotic NaCl (921 or 1,664 mosmol/kgH2O iv; 1,714 mosmol/kgH2O into renal medulla) for two further 30-min periods. Compared with isosmotic NaCl, infusion of hyperosmotic NaCl into the renal medulla significantly increased the endothelin excretion rate (P < 0.05; from 0.30 ± 0.02 to 0.49 ± 0.03 fmol/min). Intravenous infusion of hyperosmotic NaCl also significantly increased endothelin excretion rate in a concentration-dependent manner (from 0.79 ± 0.07 to 1.77 ± 0.16 fmol/min and 0.59 ± 0.04 to 1.11 ± 0.08 fmol/min for 1,664 and 921 mosmol/kgH2O, respectively). To differentiate between effects of osmolality and NaCl, similar experiments were performed using mannitol solutions. Compared with isosmotic mannitol, medullary interstitial infusion of hyperosmotic mannitol (1,820 mosmol/kg2O) significantly increased endothelin excretion rate (P < 0.05; from 0.54 ± 0.03 to 0.94 ± 0.12 fmol/min). Thus exposing the renal medulla to hyperosmotic concentrations of either NaCl or mannitol stimulates endothelin release in vivo, consistent with medullary osmolality being an important regulator of renal endothelin synthesis.

Original languageEnglish (US)
Pages (from-to)F185-F191
JournalAmerican Journal of Physiology - Renal Physiology
Volume292
Issue number1
DOIs
StatePublished - Jan 1 2007

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Endothelins
Osmolar Concentration
Kidney
Mannitol
Urine Specimen Collection
Intravenous Infusions
Epithelial Cells

Keywords

  • Mannitol
  • NaCl
  • Renal medulla

ASJC Scopus subject areas

  • Physiology
  • Urology

Cite this

Acute increases of renal medullary osmolality stimulate endothelin release from the kidney. / Boesen, Erika I.; Pollock, David M.

In: American Journal of Physiology - Renal Physiology, Vol. 292, No. 1, 01.01.2007, p. F185-F191.

Research output: Contribution to journalArticle

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