Physical and psychological capabilities during substitution therapy with recombinant growth hormone in adults with growth hormone deficiency

In a double-blind cross-over study with recombinant methionyl growth hormone (GH) and placebo during 12 weeks, the effect of GH substitution therapy (0.5-0.6 IU · kg−1 · week−1) on physical performance, muscle strength, bone mineral density, and mood and cognitive functions was investigated in 6 GH-deficient adults. During GH substitution serum concentrations of insulin-like growth factor-I and procollagen-III peptide increased in all 6 patients, whereas concentrations of serum urea decreased. Five of the patients identified the GH period and reported improved well-being with increased mental alertness and vitality and improved physical capacity and muscle strength. There was, however, no change of the isokinetic muscle strength during GH substitution therapy, and the working capacity on the bicycle ergometer was just slightly improved in some patients. The bone mineral density was low and unchanged in all patients. Mood and cognitive functions did not change during GH therapy. A reversible fluid retention was observed in one patient during the GH period. In conclusion, short-term GH substitution therapy to GH-deficient adults induced a subjective improvement of general wellbeing. Longer treatment periods will be necessary to establish the effect on physical capacity, muscle strength, bone mineral density, and mood and cognitive functions.