EFFECTS OF INSULIN-LIKE GROWTH-FACTOR-I AND GROWTH-HORMONE ON THE NETFLUX OF AMINO-ACIDS ACROSS THE HIND LIMBS IN THE SURGICALLY TRAUMATIZED PIG

1. After surgery three groups of six female pigs weighing on average 5 2.2 kg (SD 3.5) received vehicle, recombinant insulin-like factor-1 (3 64.4 mu g day(-1) kg(-1)) or recombinant human growth hormone (467.7 m -i.u. day(-1) kg(-1)) for two post-operative days. Vehicle and peptide s were infused intravenously together with total parenteral nutrition providing 129 kJ day(-1) kg(-1) non-protein calories and 0.35 g N day( -1) kg(-1). 2. On both post-operative days the mean concentration of i nsulin-like growth factor-1 in arterial blood samples was clearly belo w presurgical levels in animals receiving vehicle or recombinant human growth hormone, whereas recombinant human insulin-like growth factor- 1 infusions more than restored insulin-like growth factor-1 concentrat ions. These last samples, however, contained significantly (P < 0.05) less insulin than those from other animals. 3. Infusion of recombinant human growth factor was often associated with higher circulating leve ls of amino acids compared with recombinant human insulin-like growth factor-1 infusions. Despite this, both hormones significantly (P < 0.0 5) increased the hind limb net balance of total amino acids on postope rative day 1. Net balances of -44.2, +69.5 and +100.9 mu mol/min (pool ed SE 35.3) were associated with infusion of vehicle, recombinant huma n insulin-like growth factor-1 and recombinant human growth hormone re spectively. This response was also closely reflected in the group of n on-essential amino acids. 4. The net efflux of alanine from the hind l imbs was also significantly (P < 0.002) reduced, whereas glutamine was less affected. 5. On post-operative day 2, there was a general drop i n cortisol and urea levels, implying a loss of catabolic tone. Concomi tantly, most effects seen on amino acids flux after hormone administra tion on the previous day disappeared. 6. It is concluded that, in the acute catabolic state, both recombinant human insulin-like growth fact or-1 and recombinant human growth hormone can prevent the erosion of b ody protein by increasing the peripheral net balance of amino acids an d can thus increase the efficacy of total parenteral nutrition.