Effects of growth hormone and insulin-like growth factor 1 (IGF-1) treatments on the nitrogen metabolism and hepatic IGF-1-messenger RNA expression in postoperative parenterally fed rats.
BACKGROUND
Few studies have made direct comparisons of the metabolic effects of growth hormone (GH) and insulin-like growth factor 1 (IGF-1). We have assessed the dose-dependent effects of GH and IGF-1 treatments on nitrogen metabolism, intestinal structure, and hepatic IGF-1-messenger RNA (mRNA) expression in postoperative parenterally fed rats.


METHODS
Rats were maintained on total parenteral nutrition (TPN) for 3 days after gastrectomy. GH (0.4 or 0.8 IU/kg/d) or IGF-1 (1,2, or 4 mg/kg/d) was infused throughout the experimental period. Anabolic effects of GH and IGF-1 were assessed by body weight change, nitrogen excretion, and whole-body protein turnover. Organ weights, intestinal structure, plasma IGF-1 levels and hepatic IGF-1-mRNA contents were also determined.


RESULTS
Both GH and IGF-1 attenuated body weight loss and nitrogen excretion and increased whole-body protein synthesis and spleen weight. These observations suggest that the anabolic effects of 1 mg/kg/d of IGF-1 were equivalent to those of 0.66 IU/kg/d of GH. IGF-1, but not GH, reduced atrophy of the intestinal mucosa. GH treatment increased hepatic IGF-1-mRNA and the plasma IGF-1 level, whereas IGF-1 treatment increased the plasma IGF-1 level with no change in the hepatic IGF-1-mRNA content.


CONCLUSIONS
Administration of GH or IGF-1 attenuates catabolism after surgery. The anabolic effects of 1 mg/kg/d of IGF-1 are equivalent to those of 0.66 IU/kg/d of GH. IGF-1 reduces intestinal mucosal atrophy. GH increases hepatic IGF-1-mRNA and the plasma IGF-1 level.
Inaba
T
T
Department of Surgery, Faculty of Medicine, University of Tokyo, Japan.
Saito
H
H
Fukushima
R
R
Hashiguchi
Y
Y
Lin
M T
MT
Inoue
T
T
Fukatsu
K
K
Muto
T
T
Takenaka
A
A
Takahashi
S
S
Noguchi
T
T
D000818:Animals; D015152:Blotting, Northern; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D005998:Glycine / Q000032:analysis / Q000378:metabolism; D019382:Human Growth Hormone / Q000008:administration & dosage*; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage* / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009584:Nitrogen / Q000378:metabolism* / Q000652:urine; D009590:Nitrogen Radioisotopes; D009929:Organ Size / Q000187:drug effects / Q000502:physiology; D010288:Parenteral Nutrition; D011184:Postoperative Period; D011506:Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000008:administration & dosage
D009590:Nitrogen Radioisotopes; D011506:Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D009584:Nitrogen; D005998:Glycine