The role of orexin A in metabolic disturbances in patients with acromegaly

Introduction: It has been reported that orexins may play an important role in GM regulation. Orexins participate in the regulation of pituitary hormones secretion, food intake regulation, and the sleep-wake cycle. It has been suggested that a defect of orexin A synthesis could be responsible for disturbances in GH synthesis in patients with acromegaly, and consequently aggravate metabolic disturbances caused by high levels of IGF1. The aim of this study: The aim of this study was to assess orexin A levels in relation to the activity of the disease and the influence on metabolic profile in patients with acromegaly. Material and methods: The subjects were 55 acromegalic patients divided into three main groups: a surgically cured acromegalic group (SCA); a well-controlled acromegalic group (WCA); an active acromegalic group (AA); and 29 healthy controls. In all subjects, blood samples were taken to assess the concentration of orexin A, lipids, glucose, insulin and hormones of the pituitary and peripheral glands. Results: The concentration of orexin A was highest in the control group (CG) and lowest in the WCA group. The differences of orexin A concentration were statistically significant when each group of acromegalics were compared to the CG. There were no significant differences in orexin A concentration among the studied groups of patients with acromegaly. The metabolic disturbances were more often observed in the groups of acromegaly patients. In the AA group, orexin A concentrations correlated negatively with plasma lipids. Conclusions: The concentration of orexin A is reduced in acromegaly compared to healthy subjects. (Endokrynol Pol 2012; 63 (6): 463-469)