Growth hormone and aging.

Aging is associated with a significant decline in secretion of growth hormone. This in turn leads to reduced circulating IGF-I and changes in IGF-binding proteins. Growth hormone replacement to growth hormone-deficient individuals has been shown to improve quality of life, enhance bone and muscle mass, and reduce cardiovascular risk. However, studies with growth hormone therapy in the elderly have been somewhat disappointing with minimal changes in lean body mass, musculoskeletal function, and overall quality of life. Moreover, recent evidence suggests that high normal serum IGF-I levels may be associated with a greater risk of several neoplastic disorders. Hence, there is less enthusiasm for reversing the changes of the "somatopause" with recombinant growth factors. An overview of these issues and the prospects for the future will be discussed in this article.