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 language | English (US) |
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Pages (from-to) | 414-424 |
Number of pages | 11 |
Journal | Growth Hormone and IGF Research |
Volume | 9 |
Issue number | 6 |
DOIs | |
State | Published - Dec 1999 |
Keywords
- Cellular density
- IEC-6
- IGF-I
- IGF-II
- IGFBP-2
- Intestinal epithelium
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Endocrinology