Estrogen deficiency-induced Ca balance impairment is associated with decrease in expression of epithelial Ca transport proteins in aged female rats

Xiao Li Dong, Yan Zhang, Man Sau Wong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

11 Citations (Scopus)

Abstract

Aims The study is designed to determine whether estrogen and vitamin D endocrine systems interact to regulate calcium (Ca) balance as well as changes in mRNA expression of epithelial Ca transport proteins involved in intestinal and renal Ca transport in aging animals in response to ovariectomy and low dietary Ca intake. Main methods Eleven-month-old female sham or ovariectomized (OVX) rats were divided into four groups and fed with either a low-Ca (LCD; 0.1% Ca, 0.65% P) or a high-Ca (HCD; 1.2% Ca, 0.65% P) diet for 12 weeks. Ca balance and mRNA expression of Ca transport proteins in the intestine and kidney from rats were systematically studied. Key findings OVX rats fed with LCD resulted in a negative Ca balance. LCD suppressed serum Ca in OVX but not sham rats, resulting in an induction of serum PTH and 1,25(OH)2D3levels. The surge in serum 1,25(OH)2D3levels in LCD-fed OVX rats was associated with an increase in mRNA expression of intestinal transient receptor potential cation channel (TRPV6) and calbindin D9k (CaBP9k) as well as renal vitamin D receptor (VDR), but such an induction was unable to restore Ca balance in vivo. In contrast, the negative Ca balance was associated with suppression of intestinal plasma membrane Ca pump (PMCA1b) and renal transient receptor potential cation channel (TRPV5), calbindin D28k (CaBP28k) and PMCA1b mRNA expression in aged OVX rats. Significance Negative Ca balance in aged female OVX rats is associated with estrogen-dependent and vitamin D-independent downregulation of epithelial Ca transport protein mRNA expression.
Original languageEnglish
Pages (from-to)26-32
Number of pages7
JournalLife Sciences
Volume96
Issue number1-2
DOIs
Publication statusPublished - 6 Feb 2014

Keywords

  • Ca balance
  • Epithelial Ca transport proteins
  • Estrogen deficiency
  • High Ca diet
  • Low Ca diet

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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