Differential Impact of Medical Therapies for Acromegaly on Glucose Metabolism

Acromegaly is a rare endocrine disorder caused by excessive growth hormone (GH) production, due, in the vast majority of cases, to the presence of a GH-secreting pituitary tumour. The chronic elevation of GH and the resulting high circulating levels of insulin-like growth factor-1 (IGF-1) cause the characteristic tissue overgrowth and a number of associated comorbidities, including several metabolic changes, such as glucose intolerance and overt diabetes mellitus (DM). Elevated GH concentrations directly attenuate insulin signalling and stimulate lipolysis, decreasing glucose uptake in peripheral tissues, thus leading to the development of impaired glucose tolerance and DM. Acromegaly treatment aims to normalize plasma GH and IGF-1 levels using surgery, medical treatment, or radiotherapy. The effect of the different medical therapies on glucose homeostasis varies. This literature review explores the impact of the currently available pharmacological therapies for acromegaly (first- and second-generation somatostatin receptor ligands, a GH receptor antagonist, and dopamine agonists) on glucose homeostasis. We also discuss the underlying biological mechanisms through which they impact glucose metabolism.