Regulation of the insulin-like growth factor axis by increasing cell number in intestinal epithelial (IEC-6) cells

Mark R. Corkins, Jung H.Y. Park, Diane V. Davis, Dorothy H. Slentz, Richard G. MacDonald

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Insulin-like growth factor binding protein-2 (IGFBP-2) production as a function of cell number by intestinal epithelial cells (IEC-6) was regulated such that the IGFBP-2 concentration in 24-h conditioned medium reached a maximum, which was maintained despite increasing cell number. Northern blot analysis revealed that this effect could largely be attributed to decreasing IGFBP-2 mRNA. In contrast to IGFBP-2, secretion of IGF-II and accumulation of IGF-II mRNA by IEC-6 cells correlated positively with cell number. The highest level of IGF-II protein detected by immunoblotting of conditioned medium occurred in post-confluent cells. IGF-I stimulated the cells to grow to a high cellular density and inhibited IGFBP-2 secretion in a concentration-dependent fashion. We conclude that expression of IGF-II and IGFBP-2 are regulated in IEC-6 cells by cellular density, and IGF-II may act as a survival factor at high cell density. (C) 1999 Harcourt Publishers Ltd.

Original languageEnglish (US)
Pages (from-to)414-424
Number of pages11
JournalGrowth Hormone and IGF Research
Volume9
Issue number6
DOIs
StatePublished - Dec 1999

Keywords

  • Cellular density
  • IEC-6
  • IGF-I
  • IGF-II
  • IGFBP-2
  • Intestinal epithelium

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

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