Fetal intestinal fibroblasts respond to insulin-like growth factor (IGF)-II better than adult intestinal fibroblasts.
BACKGROUND
We compared IGF responses of fetal and adult intestinal fibroblasts to identify a developmental difference in the IGF-axis. Intestinal fibroblasts were isolated from maternal and fetal jejunum. Media was conditioned at confluence and one week afterwards. The proliferative response at confluence to 5 nM IGF-I or -II was compared.


RESULTS
There were no significant differences in IGFBP expression at confluence. Post-confluence, fetal fibroblasts had no significant changes in IGFBP-2 and IGFBP-3 expression. Post-confluent maternal fibroblasts had increased IGFBP-3 levels that were significant compared to the fetal fibroblasts. IGF-I increased in post-confluent fetal fibroblasts, while in maternal fibroblasts it decreased (p < 0.001). IGF-II secretion decreased significantly in post-confluent maternal fibroblasts (p < 0.05). Maternal fibroblasts proliferated more with IGF-I than IGF-II (p < 0.001). Fetal fibroblasts responded to IGF-II slightly better than IGF-I and significantly greater than maternal cells (p < 0.001).


CONCLUSIONS
Fetal intestinal fibroblasts respond to IGF-II with greater proliferation and do not have the increased IGFBPs seen post-confluence in adult intestinal fibroblasts.
Corkins
Mark R
MR
Division of Gastroenterology, Hepatology and Nutrition, James Whitcomb Riley Hospital for Children, Indiana University School of Medicine, Indianapolis, IN, USA, 46202. MRCorkin@pol.net
Fillenwarth
Michael J
MJ
D000367:Age Factors; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D004622:Embryo, Mammalian; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis / Q000502:physiology; D007335:Insulin-Like Growth Factor II / Q000096:biosynthesis / Q000502:physiology*; D007583:Jejunum / Q000166:cytology / Q000196:embryology / Q000502:physiology*; D011247:Pregnancy; D011863:Radioimmunoassay; D012756:Sheep; D013778:Tetrazolium Salts; D013844:Thiazoles
D017077:Culture Media, Conditioned; D013778:Tetrazolium Salts; D013844:Thiazoles; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; C022616:thiazolyl blue