Role of IGF-I in muscular atrophy of aging.

Loss of muscle mass and strength are well-known consequences of aging. The growth hormone/IGF-I pathway is both impaired with aging and essential for growth and maintenance of skeletal muscle. Despite this, growth hormone (GH) replacement has not been effective in increasing muscle mass and strength in the elderly. Possible explanations for this failure include 1. The presence of other age-related impairments in muscle that prevent the actions of GH and IGF-I and 2. Complications arising from a failure to deliver GH and IGF-I in the physiologically correct manner. This article summarizes the results of clinical trials of GH and IGF-I in the elderly and discusses the current status of strategies for safely and effectively stimulating the GH/IGF-I pathway in this population.