Insulin and glucocorticoids regulate IGFBP-1 expression via a common promoter region

Biochem Biophys Res Commun. 1994 Apr 15;200(1):226-32. doi: 10.1006/bbrc.1994.1438.

Abstract

Hepatic expression of insulin-like growth factor binding protein-1 is regulated by insulin and glucocorticoids. To study underlying mechanisms, rat hepatocytes in primary culture were transfected with deletion mutants and heterologous promoter constructs, identifying a 41 bp region of the rat insulin-like growth factor binding protein-1 promoter which is sufficient to mediate regulation by both insulin and glucocorticoids. Half maximal suppression of promoter activity by insulin occurred at a physiologic concentration, 5 x 10(-10) M, and regulation by insulin was dominant in that insulin suppressed promoter activity at all dexamethasone concentrations. Transfection of rat hepatocytes in primary culture should be a useful approach for exploring the regulation of gene expression by insulin.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Carrier Proteins / biosynthesis*
  • Carrier Proteins / genetics*
  • Cells, Cultured
  • Chloramphenicol O-Acetyltransferase / biosynthesis
  • Consensus Sequence
  • Dexamethasone / pharmacology*
  • Insulin / pharmacology*
  • Insulin-Like Growth Factor Binding Protein 1
  • Liver / drug effects
  • Liver / metabolism*
  • Male
  • Molecular Sequence Data
  • Promoter Regions, Genetic* / drug effects
  • Rats
  • Rats, Sprague-Dawley
  • Restriction Mapping
  • Sequence Deletion
  • Sequence Homology, Nucleic Acid
  • Somatomedins / metabolism
  • Transfection

Substances

  • Carrier Proteins
  • Insulin
  • Insulin-Like Growth Factor Binding Protein 1
  • Somatomedins
  • Dexamethasone
  • Chloramphenicol O-Acetyltransferase