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

Authors:
  • HSHideaki Saito
    Hideaki Saito
  • RFRyoji Fukushima
    Ryoji Fukushima
  • YHYojiro Hashiguchi
    Yojiro Hashiguchi
  • TITomomi Inoue
    Tomomi Inoue
  • KFKazuhiko Fukatsu
    Kazuhiko Fukatsu
  • TMTetsuichiro Muto
    Tetsuichiro Muto
  • ATAsako Takenaka
    Asako Takenaka
  • STShin‐Ichiro Takahashi
    Shin‐Ichiro Takahashi
  • TNTadashi Noguchi
    Tadashi Noguchi
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Abstract
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. (Journal of Parenteral and Enteral Nutrition 20:325–331, 1996)

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