It has been reported that orexins play an important role in the regulation of GH secretion. It is suggested that the defect in orexins synthesis could be responsible for the disturbances in GH synthesis and consequently aggravate metabolic disturbances. The aim of the study was to assess plasma orexin A levels in patients with acromegaly in relation to the activity of disease and hormonal and metabolic profiles. Fifty-five patients with acromegaly divided into three groups accordingly to minimal GH during OGTT and IGF1 concentrations were studied: 18 with surgically cured acromegaly (SCA), 17 during treatment with a long-acting octreotide were well controlled acromegalic group (WCA), 20 ones, who did not meet the criteria for the cure or disease control, were included in the active acromegalic group (AA). Twenty-nine healthy subjects were enrolled to the control group (CG). In all subjects the concentration of orexin A, GH, IGF1, lipids, glucose, insulin, and other hormones were analyzed. Adipose tissue content was studied by the DXA method.
Results: The concentration of orexin A was the highest (39.29±11.51 pg/ml) in CG and the lowest (26.76±17.17 pg/ml) in WCA group. Orexin A concentrations were statistically significantly lower in each group of acromegalics when compared to CG. There were no differences in orexin A among the groups of acromegaly patients. The tendency to negative correlation between orexin A and GH in 0 and 60 min during OGTT was observed, it was statistically significant in AA group. In AA group orexin A concentrations correlated negatively with serum lipids. In each group of the studied patients the tendency to negative correlation between orexin A and insulin was observed. Conclusions: Orexin A concentration is reduced in patients suffering from acromegaly, regardless the activity of the disease. Orexin A deficiency may increase the metabolic abnormalities in acromegaly.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This work was supported, however funding details unavailable.