Somatopause reflects age-related changes in the neural control of GH/IGF-I axis

This paper will focus on the hypofunction of GH/IGF-I axis in aging, as the most impressive example of decreased activity as function of age-related changes in the neural control of somatotroph cells. GH secretion undergoes clear age-related variations that are generally mirrored by IGF-I levels, the best marker of GH status. Given the well known positive influence of GH/IGF-I on body composition, structure functions and metabolism, this paper discusses the potential clinical implications, also taking into account evidence showing that, at least in animals, deficiency in GH/IGF-I is somewhat associated to prolonged life. Although somatopause is likely to contribute to age-related changes in body composition, structure functions and metabolism, we are now in front of the paradox of lifelong GH/IGF-I deficiency or resistance resulting in prolonged life expectancy and GH replacement at advanced age, probably exerting anti-aging effects. This evidence questions whether GH deficiency is or not a beneficial adaptation to aging. By answering this question one is not simply finding new phylosophical paradigm but also the rational basis for anti-aging drug interventions.