These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Maturation of the Na+/H+ antiporter (NHE3) in the proximal tubule of the hypothyroid adrenalectomized rat.
    Author: Gupta N, Dwarakanath V, Baum M.
    Journal: Am J Physiol Renal Physiol; 2004 Sep; 287(3):F521-7. PubMed ID: 15113742.
    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 approximately 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.
    [Abstract] [Full Text] [Related] [New Search]