GH elevates serum IGF-I levels but does not alter mucosal atrophy in parenterally fed rats.
Growth hormone (GH) action is primarily mediated by insulin-like growth factor I (IGF-I), although both growth factors show tissue-selective effects. We investigated the effects of GH, IGF-I, and GH plus IGF-I on jejunal growth and function in rats maintained with total parenteral nutrition (TPN) and given recombinant human GH (rhGH) (400 micrograms/day sc, twice daily) and/or rhIGF-I (800 micrograms/day in TPN solution) for 5 days. Administration of GH or IGF-I alone produced similar increases in serum IGF-I levels and body weight; GH plus IGF-I further increased these parameters. TPN reduced mucosal mass, protein and DNA content, villus height, crypt depth, and enterocyte migration rate. IGF-I or GH plus IGF-I produced equivalent increases in all intestinal growth parameters; GH alone had no effect. GH, IGF-I, or GH plus IGF-I reduced TPN-induced increases in sucrase-specific activity. IGF-I, but not GH, attenuated TPN-induced increases in tissue conductance and carbachol-stimulated ion secretion. In contrast to IGF-I, GH does not stimulate intestinal growth during TPN and has less effect on normalizing TPN-induced changes in epithelial function.
Peterson
C A
CA
Department of Nutritional Sciences, University of Wisconsin, Madison 53706, USA.
Carey
H V
HV
Hinton
P L
PL
Lo
H C
HC
Ney
D M
DM
D000818:Animals; D001284:Atrophy; D001692:Biological Transport; D001835:Body Weight; D019382:Human Growth Hormone / Q000494:pharmacology*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology*; D007421:Intestine, Small / Q000378:metabolism / Q000473:pathology; D007583:Jejunum / Q000378:metabolism / Q000473:pathology; D007700:Kinetics; D008297:Male; D008871:Microvilli / Q000201:enzymology; D009929:Organ Size; D009994:Osmolar Concentration; D010289:Parenteral Nutrition, Total; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins
D011994:Recombinant Proteins; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I