Insulin-like growth factor I regulates type I procollagen messenger ribonucleic acid steady state levels in bone of rats

Endocrinology. 1989 Sep;125(3):1575-80. doi: 10.1210/endo-125-3-1575.

Abstract

RNA extracted from parietal bones of rats was analyzed for the abundance of type I procollagen mRNA by a dot hybridization assay using specific cDNA probes. Hypophysectomized rats, deficient in IGF I, have 4.1-fold lower steady state levels of mRNA encoding the alpha 1 chain of type I collagen when compared to normal rats of the same weight (120 g). Administration of recombinant human insulin-like growth factor I (IGF I) for 6 days restores bone collagen mRNA levels to normal, and a single sc injection of 100 micrograms IGF I results in a 1.9-fold increase of both alpha 1(I) and alpha 2 (I)chain mRNAs after 8 h. Studies with calvaria cells in primary culture and with a bone-derived cell line, PyMS, yielded similar results: IGF I treatment of these osteoblast-like cells for 24 h increased steady state levels of type I procollagen mRNAs. Thus, IGF I appears to contribute to osteoblast mRNA expression for both chains of type I collagen.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Northern
  • Bone and Bones / drug effects
  • Bone and Bones / metabolism*
  • Cells, Cultured
  • Cloning, Molecular
  • DNA / genetics
  • Hypophysectomy
  • Insulin-Like Growth Factor I / pharmacology*
  • Male
  • Nucleic Acid Hybridization
  • Osteoblasts / drug effects
  • Osteoblasts / metabolism*
  • Plasmids
  • Procollagen / genetics*
  • RNA, Messenger / drug effects
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism*
  • Rats
  • Rats, Inbred Strains
  • Somatomedins / pharmacology*

Substances

  • Procollagen
  • RNA, Messenger
  • Somatomedins
  • Insulin-Like Growth Factor I
  • DNA