Diabetes in Growth Hormone Deficiency

Growth hormone (GH) deficiency (GHD) is a complex disease with a constellation of symptoms and signs which involve metabolism at several levels. Particular attention has been paid to glucose and insulin regulation by the GH and insulin-like growth factor 1 axis with contrasting results in in vitro and in vivo studies, as also in untreated and treated GHD subjects. The fact that GH shares the same signaling molecules as insulin is a reason for both insulin-mimetic and insulin-antagonistic actions of the hormone. Moreover, GHD seems to have a differing impact on glucose metabolism and the risk of developing diabetes across the lifespan from neonates to elderly. Further risk factors like family history, visceral obesity and lifestyle may have a detrimental role. The aim of this chapter is to critically review the up-to-date evidence on diabetes and glucose alterations in treated and untreated GHD patients in order to ensure the correct management of these patients in each phase of their life.