EFFECT OF POSTOPERATIVE INSULIN-LIKE GROWTH-FACTOR-I SUPPLEMENTATION ON PROTEIN-METABOLISM IN HUMANS

Insulin-like growth factor I (IGF-I) has been shown experimentally to exert a nitrogen-sparing effect in both animals and humans. Its effect s on protein metabolism during the first 5 days after radical large bo wel resection were investigated. Nineteen patients were randomly alloc ated to receive either human recombinant IGF-I (2 x 80 mu g/kg body we ight subcutaneously, n=10) or placebo (n=9) starting on the morning of the first day after operation. All patients received parenteral nutri tion (glucose 3g and nitrogen 0.1g/kg/day). The mean(s.e.m.) urinary n itrogen:creatinine ratio was significantly reduced in patients who rec eived IGF-I compared with those given placebo (275.0(17.1) compared wi th 386.3(23.6), P < 0.01). The mean urinary 3-methylhistidine: creatin ine ratio and nitrogen balance were lower in the IGF-I group, but not significantly so. Plasma IGF-I concentrations were four times higher i n the treated group compared with those in the placebo group. Insulin- like growth factor binding protein 3 (IGFBP-3) increased significantly after the start of IGF-I treatment, compared with mean postoperative levels. The mean blood glucose concentration was significantly lower i n the IGF-I:group than the placebo group (P < 0.05) but no patient had a hypoglycaemic attack. The authors conclude that IGF-I does not sign ificantly influence the nitrogen balance, but that results indicate a possible nitrogen-sparing effect in patients after major abdominal ope rations. IGF-I therapy is safe, and may be of value in catabolic patie nts after serious injury and major operations.