title: Effects of insulin-like growth factor on nitrogen balance during hypoxic exposure.
abstract: Acute exacerbations of chronic obstructive pulmonary disease (COPD) accompanied with hypoxaemia may induce net protein catabolism and hypoxaemia could be an important trigger of a systemic catabolic response. The aim of this study was to examine the anabolic effects of recombinant human insulin-like growth factor-I (IGF-1) in rats exposed to hypoxia. Although acute hypoxia is usually accompanied with a decrease in dietary intake, the usual nitrogen intake was maintained in this study. Sprague-Dawley rats were maintained by continuous infusion of solution for total parenteral nutrition for 6 days. The animals were then randomly assigned to a normoxic (N) or a hypoxic (H) group. During the last 3 days of the experiment N and H rats were randomised to receive either IGF-I or vehicle. Exposure to hypoxia caused a decrease in body-weight gain accompanied by a negative nitrogen balance, which was mainly due to increased urinary nitrogen excretion. No effect of recombinant human IGF-I treatment on body weight was observed during exposure to hypoxia, although nitrogen balance normalised. The co-infusion of recombinant human insulin-like growth factor-1 and total parenteral nutrition has a significant net anabolic effect, as demonstrated by nitrogen retention and reduction in urine protein excretion observed in rats. Insulin-like growth factor-1 may help to ameliorate the protein catabolism observed under hypoxic conditions.
authors.affiliation: Dept of Respirology, Graduate School of Medicine, Chiba University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Iioka
authors.forename: K
authors.initials: K
authors.lastname: Tatsumi
authors.forename: K
authors.initials: K
authors.lastname: Sugito
authors.forename: T
authors.initials: T
authors.lastname: Moriya
authors.forename: T
authors.initials: T
authors.lastname: Kuriyama
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004357:Drug Synergism; D006801:Humans; D000860:Hypoxia / Q000097:blood* / Q000652:urine*; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009584:Nitrogen / Q000097:blood* / Q000652:urine*; D010289:Parenteral Nutrition, Total; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D014882:Water-Electrolyte Balance / Q000187:drug effects*; D015431:Weight Loss / Q000187:drug effects*
chemical_list: D007334:Insulin-Like Growth Factor I; D009584:Nitrogen