Production of insulin-like growth factor I (IGF-I) and IGF-binding proteins by rat intestinal stromal cells in vitro.
To determine if intestinal stromal cells secrete diffusible factors such as insulin-like growth factors (IGFs) capable of regulating epithelial cell growth in vitro, stromal cells were isolated by enzymatic digestion of rat intestine. Incorporation of [3H]thymidine into DNA and [14C]leucine into protein of IEC-6 cells, a model intestinal epithelial cell line, was significantly increased (two- to threefold) when the IEC-6 cells were co-cultured with stromal cells, relative to IEC-6 cells grown alone. Medium conditioned by stromal cells stimulated DNA synthesis of IEC-6 cells in a dose-dependent manner. Analysis of the conditioned medium revealed that intestinal stromal cells secreted IGF-I, but little IGF-II, in addition to an M(r) 32,000 IGF-binding protein (IGFBP-2) and an IGFBP having M(r) approximately 24,000. We conclude that rat intestinal stromal cells secrete one or more diffusible factors, which may include IGF-I and IGFBPs, capable of stimulating proliferation of IEC-6 cells in vitro.
MacDonald
R G
RG
Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha 68198-4525, USA.
McCusker
R H
RH
Blackwood
D J
DJ
Vanderhoof
J A
JA
Park
J H
JH
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004247:DNA / Q000096:biosynthesis; D018969:Insulin-Like Growth Factor Binding Proteins / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007422:Intestines / Q000502:physiology*; D008297:Male; D014176:Protein Biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017154:Stromal Cells / Q000378:metabolism*
D017077:Culture Media, Conditioned; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I; D004247:DNA