To examine the
protein anabolic actions of
insulin in
chronic renal failure, the authors measured four sets of whole body
leucine fluxes during
insulin alone and
insulin with
amino acid infusion in nine uremic patients before
hemodialysis (B-HD). Seven were restudied 8 wk after initiation of maintenance
hemodialysis (HD). Six normal subjects served as control (N). All values ( micro mol/kg/h, mean +/- SEM) are presented in the sequence of B-HD, HD, and N, and only P < 0.05 are listed. During Flux 1 (baseline), D (
leucine release from body protein degradation) were 114 +/- 7, 126 +/- 4, and 116 +/- 6, respectively. C (
leucine oxidation rates) were 18 +/- 2, 17 +/- 2, and 21 +/- 3, respectively. S (
leucine disappearance into body
protein [index of
protein synthesis]) were 96 +/- 6, 107 +/- 4, and 94 +/- 4, respectively, and balances (net
leucine flux into
protein [values were negative during fasting]) were -18 +/- 2, -17 +/- 2, and -21 +/- 3, respectively. During Flux 2 (low-dose
insulin infusion), D were 89 +/- 3, 98 +/- 6, and 94 +/- 5, respectively; C were 12 +/- 1, 11 +/- 2, and 18 +/- 1, respectively (P = 0.02); S were 77 +/- 4, 87 +/- 5, and 76 +/- 5, respectively, and balances were -12 +/- 1, -11 +/- 2, and -18 +/- 1, respectively (P = 0.02). During Flux 3 (high-dose
insulin infusion): D were 77 +/- 3, 82 +/- 7, and 84 +/- 5, respectively; C were 9 +/- 1, 8 +/- 1, and 14 +/- 1, respectively (P = 0.005); S were 68 +/- 4, 74 +/- 6, and 70 +/- 5, respectively, and balances were -9 +/- 1, -8 +/- 1, and -14 +/- 1, respectively (P = 0.005). In Flux 4 (
insulin infused with
amino acids): D were 73 +/- 3, 107 +/- 18, and 85 +/- 7, respectively; C were 35 +/- 4, 29 +/- 5, and 39 +/- 3, respectively; S were 105 +/- 5, 145 +/- 15, and 113 +/- 6, respectively (P = 0.02), and balances were 32 +/- 4, 38 +/- 5, and 27 +/- 3, respectively. These data show that B-HD and HD patients were as sensitive as normal subjects to the
protein anabolic actions of
insulin.
Insulin alone reduced proteolysis and
leucine oxidation, and
insulin given with
amino acids increased net
protein synthesis.