Introduction

The anabolic and lipolytic effects of growth hormone (GH) and thereby the effects upon muscle and fat tissue have been known for many years. Already in 1934, increased muscle mass and reduced body fat was reported in rats after administration of anterior pituitary extracts (Lee & Shaffer, 1934). In children, where GH replacement therapy was introduced in 1957, it was soon observed that GH administration not only affected skeletal growth, but also significantly changed body composition (Tanner & Whitehouse, 1967). In GH-deficient adults the first controlled clinical trials on the effect of GH treatment also reported profound effects on muscle and fat mass (Jørgensen et al., 1989; Salomon et al., 1989). The subsequent – and still ongoing – discussions about whether or not GH-deficient adults should be offered GH replacement therapy have to some extent focused on the beneficial effects on body composition. It has been argued that many of the beneficial effects reported after GH replacement therapy in adults are ‘cosmetic’ and do not justify that this expensive treatment should be offered on a routine basis. The effects on body composition should, however, not be seen as an isolated phenomenon, but rather as the integrated results of the well documented metabolic actions of GH – described elsewhere in this volume. Furthermore, there exists a rather complex relationship between ageing, body composition and GH secretion, which is important to take into consideration in the diagnostic process in elderly patients suspected for GH deficiency (GHD).

Assessing and monitoring body composition, therefore, has become an important clinical tool in the management of adult GHD.