Maturation of the Na+/H+ antiporter (NHE3) in the proximal tubule of the hypothyroid adrenalectomized rat

Neena Gupta, Vangipuram Dwarakanath, Michel Baum

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

In previous studies examining the role of glucocorticoids and thyroid hormone on the maturation of the Na+/H+ antiporter (NHE3), we found attenuation in the maturational increase in proximal tubule apical Na+/H+ antiporter activity but no change in NHE3 mRNA abundance in either glucocorticoid-deficient or hypothyroid rats. In addition, prevention of the maturational increase in either hormone failed to totally prevent the maturational increase in Na+/H+ antiporter activity. We hypothesized that one hormone played a compensatory role when the other was deficient. The present study examined whether combined deficiency of thyroid and glucocorticoid hormones would completely prevent the maturation of the Na+/H+ antiporter. Adrenalectomy was performed in 9-day-old hypothyroid Sprague-Dawley rats, a time before the normal postnatal maturational increase in these hormones occurs. Nine- and 30-day-old adrenalectomized (ADX), hypothyroid rats had comparable NHE3 mRNA abundance, which was 5- to 10-fold less than 30-day-old ADX, hypothyroid rats that received corticosterone-thyroxine replacement and 30-day-old sham control rats (P < 0.05). Brush-border membrane NHE3 protein abundance was comparable in 9- and 30-day-old ADX, hypothyroid groups and ∼20-fold lower than both the 30-day replacement and 30-day sham groups (P < 0.05). Similarly, the replacement and sham groups had higher sodium-dependent proton secretion than 9- and 30-day-old ADX, hypothyroid groups (P < 0.05). We conclude that combined deficiency of both hormones totally prevents the maturational increase in NHE3 mRNA and protein abundance and Na+/H+ antiporter activity.

Original languageEnglish (US)
Pages (from-to)F521-F527
JournalAmerican Journal of Physiology - Renal Physiology
Volume287
Issue number3 56-3
DOIs
StatePublished - Sep 2004

Keywords

  • Adrenalectomy
  • Cell pH
  • Micro perfusion
  • NHE3
  • Renal development

ASJC Scopus subject areas

  • Physiology
  • Urology

Fingerprint Dive into the research topics of 'Maturation of the Na<sup>+</sup>/H<sup>+</sup> antiporter (NHE3) in the proximal tubule of the hypothyroid adrenalectomized rat'. Together they form a unique fingerprint.

Cite this