Aging and growth hormone.

Detailed studies of the ontogeny of growth hormone (GH) secretion have shown unequivocally that GH is produced throughout life but secretion declines progressively to about 20% of that in puberty. These changes are accounted for in part by changes in central neuro-endocrine function, nutritional factors and by changes in sex steroid milieu. Mean 24-hour GH concentrations in the normal elderly are frequently below the limit of assay detectability where values are indistinguishable from matched adults with organic GH deficiency. The notion that diminished GH action may account for the undesirable changes in body composition and function in the elderly is supported by beneficial findings of GH treatment in GH-deficient adults. Preliminary results of GH treatment in the normal elderly suggest beneficial effects on body composition but a high incidence of side-effects. Questions addressing cost, benefit, dosage, safety and tolerance need to be critically addressed before GH can be considered for use in the aging.