Growth hormone and the expression of mRNAs for matrix proteins and oncogenes in bone

Mohammed A. Salih, Paul B. Orhii, Cang Chen, Dike N. Kalu

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

To examine the effects of growth hormone (GH) on the expression of the mRNAs of bone matrix proteins, three experiments were carried out with 3- month-old female Sprague-Dawley rats. In the first experiment rats were given a single subcutaneous injection of recombinant human GH (8 mg rhGH/kg b. wt.), sacrificed 15 min, 1 h, 2 h, 4 h, 8 h, 16 h and 24 h later, and RNA isolated from cancellous bone from the distal femoral metaphysis. Growth hormone increased the level of type I collagen mRNA by 187, 417, and 509% over the control level at 15 min, 1 h and 2 h, respectively; the mRNA levels declined to 119 and 99% at 4 and 8 h, respectively, and then rose again to 351 and 423% over the control level at 16 and 24 h, respectively. Osteocalcin mRNA transcript increased by 89, 90, 325, 342, 361, and 407% over the control level at 15 min, 1 h, 2 h, 4 h, 8 h and 16 h, respectively, and fell to 66% at 24 h. The level of IGF-I mRNA increased by 45, 83, 120, 140, and 175% over the control level at 2, 4, 8, 16, and 24 h, respectively. In the second experiment, following the administration of rhGH (8 mg/kg b. w.t.) bone osteocalcin mRNA increased by 127, 177, 361, and 413% over the control level at 30 min, 1 h, 2 h and 4 h, respectively; IGF-I mRNAs increased by 38, 33, 87, and 437 at 30 min, 1 h, 2 h and 4 h, respectively, but the levels did not become significant until 2 h; c-fos mRNA increased significantly at 30 min, and c-jun and c-myc mRNAs did not increase until 4 h. In the third experiment, animals were given a single injection of rhGH (8 mg/kg b. wt.) and the animals were bled at timed intervals and acid ethanol-extractable serum IGF-I determined. Serum IGF-I increased significantly only at 12 h following rhGH administration. Our data indicate that GH stimulates a rapid increase in the expression of mRNAs for the bone matrix proteins, type I collagen and osteocalcin, by a mechanism that appears to be independent of IGF-I, the early response oncogenes or an increase in osteoblast number.

Original languageEnglish (US)
Pages (from-to)149-159
Number of pages11
JournalMolecular and Cellular Endocrinology
Volume147
Issue number1-2
DOIs
StatePublished - Jan 25 1999
Externally publishedYes

Keywords

  • c-fos
  • c-jun
  • c-myc
  • Osteocalcin, IGF-I
  • Type I collagen

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Endocrinology

Fingerprint

Dive into the research topics of 'Growth hormone and the expression of mRNAs for matrix proteins and oncogenes in bone'. Together they form a unique fingerprint.

Cite this