HUMAN GROWTH HORMONE (GH) TREATMENT OF IMMATURE MALE MONKEYS FOR SIX MONTHS

Abstract

Little is known about the effect of exogenous GH to accelerate or disrupt statural development in normally growing primates. Prepubertal male rhesus monkeys were injected for 2 months with placebo (sc daily) and then randomized to treatment groups by body weight (BW). They were then treated daily with placebo or recombinant human GH (rhGH) at 0.05 or 0.35 mg/kg for 6 months. The placebo monkeys grew as expected, with significant increases in BW gain, tibial length, skeletal maturation score (SMS) and crown-rump length (CRL); these also had a stable IGF-1 baseline. Both groups treated with rhGH had significant increases in BW, while only the high dose group had an increase in CRL (+31%) greater than placebo controls. The IGF-1 areas under the treatment curves were also elevated above placebo in the rhGH groups (+46% & +51%). There were no anti-rhGH antibodies measured in the high rhGH dose monkeys. No group differences were observed in fasting insulin, glucose, cortisol, testosterone, triglycerides, urea nitrogen, cholesterol, albumin, calcium, alkaline phosphatase or alanine transaminase. We conclude that this rhGH treatment regimen over 6 mo did not disrupt the normal growth pattern of prepubertal monkeys. Daily exposure to rhGH enhanced BW gain, CRL and IGF-1 levels. Changes in tibial length and SMS were not different from placebo controls.