Effects of growth hormone on body composition and bone metabolism

Physiologic effects of growth hormone (GH) extend beyond the stimulation of linear growth during childhood and adolescence. These effects include buil ding and sustaining lean body mass, facilitating the utilization of fat mas s for energy needs, and maintaining bone mineral density. These nongrowth e ffects of GH appear to be important throughout life. Children and adults wi th severe GHD demonstrate marked reductions in lean body mass, increases in percent body fat, and subnormal bone mineral density. Replacement of GH at tenuates these abnormalities, though it remains unknown whether it does so completely. Children with body composition abnormalities resembling the GHD state (e.g., Prader-WiIli syndrome) also appear to respond favorably to ad ministration of GH treatment, and demonstrate concomitant improvements in s trength and agility. Long-term body composition benefits of GH supplementat ion in these and other non-GHD individuals remain unproven.