Estrogen modulates the mRNA levels for cancellous bone protein of ovariectomized rats

Mohammed A. Salih, Chung Ching Liu, Bahram H. Arjmandi, Dike N. Kalu

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

This study was undertaken to examine the effects of ovariectomy and 17β-estradiol (E2) on the gene expression of type 1 collagen, osteocalcin and the protooncogen, c-myc, in cancellous bone. Female Sprague-Dawley rats, aged 95 days, were divided into 4 groups. Group 1 was sham operated and Groups 2–4 were ovariectomized. Groups 3 and 4 received daily injections of 160 ng and 1600 ng E2/kg body weight, respectively. Groups 1 and 2 received the solvent vehicle. All animals were sacrificed after 14 days. The femurs were dissected out and cancellous bone scraped from the distal metaphysis. RNA was isolated from the cancellous bone, immobilized on filters or size-fractionated by agarose gel electrophoresis and adsorbed on filters which were then hybridized with specific cDNA probes. Ovariectomy resulted in a significant increase in the mRNAs of type 1 collagen, osteocalcin and c-myc. The increase was suppressed in animals that received 17β-estradiol injections. In addition, ovariectomy caused the expected decrease in cancellous bone in the proximal tibia and increased osteoclast and osteoblast numbers. The ovariectomy-induced changes were prevented by 17β-estradiol administration. These findings suggest that the lack of ovarian hormones shortly after ovariectomy up-regulates and estrogen administration down-regulates the expression of important cancellous bone matrix proteins as well as the protooncogen, c-myc.

Original languageEnglish (US)
Pages (from-to)285-299
Number of pages15
JournalBone and Mineral
Volume23
Issue number3
DOIs
StatePublished - 1993
Externally publishedYes

Keywords

  • 17β-Estradiol
  • Bone loss
  • c-myc mRNA
  • Osteocalcin mRNA
  • Ovariectomy
  • Type 1 collagen mRNA

ASJC Scopus subject areas

  • Surgery
  • Biochemistry
  • Endocrinology

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