Comparative effect of cyclosporin A and G on weight gain of primates during the pubertal growth period.
A double-blind study with six cynomolgus monkeys (mean age, 2.0 years) was carried out. All animals received immunosuppression therapy with 16 mg/kg/day of cyclosporin A or G (Norvaline cyclosporine), given intramuscularly in two divided daily dosages. All animals received a small dosage of steroids (0.1 mg/kg/day). After 14 months the dosage of cyclosporin G was increased to 20 mg/kg/day. During the first study year, weight velocity was normal in the cyclosporin G group and impeded in the group receiving cyclosporin A. During the second year of the study, the weight velocity was impeded in both groups. The weight gain was significantly less in the cyclosporin A group than in the group receiving cyclosporin G (p = 0.001). The results suggested that cyclosporine impeded weight gain in primates during the pubertal period. The effect was dosage-related and was less with cyclosporin G than with cyclosporin A. The mechanism is unclear, but the possible effect on the growth hormone merits further studies.