Growth hormone and lean tissue catabolism during long-term glucocorticoid treatment

Abstract
The aim of the study was to determine whether growth hormone (GH) treatment decreased net protein catabolism of lean tissues in patients receiving chronic glucocorticoid treatment. Whole body leucine kinetics were measured in post-absorptive conditions using a 1-14C-leucine infusion before and during GH administration (0.0125 mg/kg/day; 0.033 U/kg/day) for 7 days. We studied four patients (age range 31-71 years) who had taken prednisone (mean +/- SEM 0.21 +/- 0.03 mg/kg/day, total dose 10-27.5 mg/day) for longer than 5 months for various lung diseases. During GH treatment leucine oxidation decreased (baseline 0.44 +/- 0.07 vs GH 0.37 +/- 0.05 mumol/kg lean body mass/min, P = 0.01) and non-oxidative leucine disposal increased (1.95 +/- 0.10 vs 2.05 +/- 0.09 mumol/kg lean body mass/min, P = 0.02) but leucine appearance was unaltered. We conclude that GH decreased amino acid catabolism and improved protein synthesis without altering protein breakdown in patients receiving chronic glucocorticoid treatment. There may be a role for GH in mitigating the protein catabolic side-effects of prolonged glucocorticoid treatment.