Hormone Replacement Therapy and Physical Function in Healthy Older Men. Time to Talk

[Mike Bikov]

Endocr Rev. 2012 Mar 20. [Epub ahead of print]
Hormone Replacement Therapy and Physical Function in Healthy Older Men. Time to Talk Hormones?
Giannoulis MG, Martin FC, Nair KS, Umpleby AM, Sonksen P.
Source

Consultant Endocrinologist (M.G.G.), Thessaloniki 54622, Greece; Guy's and St. Thomas' National Health Service Foundation Trust (F.C.M.), and Institute of Gerontology (F.C.M.), King's College, London WC2R 2LS, United Kingdom; Division of Endocrinology (K.S.N.), Mayo Clinic, Rochester, Minnesota 55905; Department of Human Metabolism, Diabetes, and Metabolic Medicine (A.M.U.), Postgraduate Medical School, University of Surrey, Guildford GU2 7WG, United Kingdom; St. Thomas' Hospital and King's College (P.S.), London SE1 7EW, United Kingdom; and Southampton University (P.S.), SO17 1BJ, Southampton, United Kingdom.
Abstract

Improving physical function and mobility in a continuously expanding elderly population emerges as a high priority of medicine today. Muscle mass, strength/power, and maximal exercise capacity are major determinants of physical function, and all decline with aging. This contributes to the incidence of frailty and disability observed in older men. Furthermore, it facilitates the accumulation of body fat and development of insulin resistance.Muscle adaptation to exercise is strongly influenced by anabolic endocrine hormones and local load-sensitive autocrine/paracrine growth factors. GH, IGF-I, and testosterone (T) are directly involved in muscle adaptation to exercise because they promote muscle protein synthesis, whereas T and locally expressed IGF-I have been reported to activate muscle stem cells. Although exercise programs improve physical function, in the long-term most older men fail to comply. The GH/IGF-I axis and T levels decline markedly with aging, whereas accumulating evidence supports their indispensable role in maintaining physical function integrity.Several studies have reported that the administration of T improves lean body mass and maximal voluntary strength in healthy older men. On the other hand, most studies have shown that administration of GH alone failed to improve muscle strength despite amelioration of the detrimental somatic changes of aging. Both GH and T are anabolic agents that promote muscle protein synthesis and hypertrophy but work through separate mechanisms, and the combined administration of GH and T, albeit in only a few studies, has resulted in greater efficacy than either hormone alone. Although it is clear that this combined approach is effective, this review concludes that further studies are needed to assess the long-term efficacy and safety of combined hormone replacement therapy in older​

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