Resection upregulates the IGF-I system of parenterally fed rats with jejunocolic anastomosis.
Rats maintained with parenteral nutrition following 60% jejunoileal resection plus cecectomy exhibit minimal adaptive growth in the residual jejunum but a dramatic adaptive growth in the residual colon. Coinfusion of insulin-like growth factor I (IGF-I) with parenteral nutrition induces jejunal growth but has minimal effects in the colon. Our objective was to study the role of the endogenous IGF-I system in the differential responses of jejunum and colon to resection and/or IGF-I during parenteral nutrition. We measured concentrations of immunoreactive IGF-I in plasma, jejunum, and colon, IGF-I receptor binding, and levels of IGF receptor, IGF-I, IGF binding protein (IGFBP)-3 and IGFBP-5 mRNA in residual jejunum and colon 7 days after resection and/or IGF-I treatment. IGF-I receptor number was increased (74-99%) in jejunum and colon due to resection; IGF-I mRNA was increased 5-fold in jejunum and 15-fold in colon due to resection. Resection increased circulating IGFBPs but did not alter plasma IGF-I concentration. Resection induced colonic growth in association with significantly greater colonic IGFBP-5 mRNA and significantly lower colonic immunoreactive IGF-I. IGF-I treatment had no significant effect on IGF-I mRNA or IGF-I receptor number. Concentrations of plasma and jejunal immunoreactive IGF-I were significantly increased in rats given IGF-I in association with jejunal growth. IGF-I treatment significantly increased IGFBP-5 mRNA in the jejunum, which also correlated with jejunal growth. Thus resection upregulated IGF-I receptor number and IGF-I mRNA in residual jejunum and colon, but differential adaptation of these segments correlated with differential regulation of IGFBP-5 mRNA.
Gillingham
M B
MB
Department of Nutritional Sciences, University of Wisconsin-Madison, 53706, USA.
Kritsch
K R
KR
Murali
S G
SG
Lund
P K
PK
Ney
D M
DM
D000714:Anastomosis, Surgical; D000818:Animals; D001835:Body Weight; D003106:Colon / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000235:genetics; D018975:Insulin-Like Growth Factor Binding Protein 5 / Q000235:genetics; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000473:pathology; D007583:Jejunum / Q000378:metabolism / Q000601:surgery*; D008297:Male; D009929:Organ Size; D010288:Parenteral Nutrition; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017526:Receptor, IGF Type 1 / Q000235:genetics; D015854:Up-Regulation
D018972:Insulin-Like Growth Factor Binding Protein 3; D018975:Insulin-Like Growth Factor Binding Protein 5; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1