Effects of six-month administration of recombinant human growth hormone to healthy elderly subjects

In aging, both changes in body composition and a decrease in GH secretion are observed. While recombinant human GH (rhGH) therapy was shown to be effective in GH-deficient adults, its effects on normal aging are controversial. This study addressed the effects of six-month administration of lour dosages of rhGH in a group of 5 healthy elderly subjects (age range 71-86 years). All subjects received 2 IU rhGH (Saizen, Serono) x 2/week s.c., which was approximately 0.03 mg/kg/week, and were examined before and 1, 3, and 6 months after the start of the therapy, as well as 3 months after therapy teas suspended. Hormonal, metabolic and biochemical parameters, as well as bone density at the forearm level; body composition and muscle strength, assessed by isokinetic exercises, were evaluated at each scheduled visit. After the start of the therapy, there was an average 9+/-3 % increase (median 8%) in IGF-I levels (IGF-I basal: 145.6+/-9 ng/mL, IGF-I peak: 176.0+/-10; p<0.001). An increase in lean body weight, a decrease in fat (p<0.05) and an improvement in muscle strength (p<0.01) were recorded. No significant variation was observed in the metabolic parameters. During rhGH therapy, an increase in both bone resorption and formation parameters, and a slightly decreasing trend in bone density were noted. In conclusion, low dosages of rhGH in healthy elderly subjects seem to determine some physiological effects, such as a slight increase in IGF-I levels, which in turn may be responsible for the positive effects on body mass composition and muscle strength, without producing side effects. On the other hand, 6-month subcutaneous rhGH therapy at the dosage employed teas unable to improve bone density. (C) 1997, Editrice Kurtis.