Endocrine Abstracts

Purpose: Acromegaly is a disease characterized by the excessive secretion of GH. Clinically, it is manifested by overgrowth of tissues and internal organs, which leads to characteristic phenotype. Patients with active acromegaly usually have impaired glucose metabolism. It significantly improves after achieving remission of the disease. Adversely, disturbances in lipid profile are not altering. Moreover, these parameters are even worse in successfully treated patients. Ghrelin strongly stimulates growth hormone secretion from anterior pituitary, as well as regulates the energy balance and various metabolic parameters. It is known that ghrelin affects glucose and lipid metabolism. It was shown that ghrelin level changes during treatment of acromegaly in earlier papers. Ghrelin occurs in acylated (AG) or unacylated (UG) form. Unacylated protein until recently was considered to be inactive. However, the latest research suggested that both forms may play biological functions. We aimed to evaluate the levels of total, acylated and unacylated ghrelin in medically naive and treated patients with biochemically active acromegaly in respect to variables of lipid and glucose metabolism.

Methods: The study group consisted of 24 patients diagnosed with active acromegaly. In study group nine patients were newly diagnosed and 16 patients received somatostatin analogs (9 lanreotide, 6 octreotide). Fifteen healthy volunteers served as controls. The physical examination of each subject was performed. Plasma levels of total ghrelin (TG), AG, calculated UG, GH, IGF1, insulin, glucose, total cholesterol, HDL cholesterol and calculated LDL cholesterol, triglycerides, apolipoproteins A-I (apoA-I) and B-100 (apo B-100) were measured.

Results: Total ghrelin levels in patients with acromegaly were decreased compared to healthy controls. In pooled data of all subgroups, simple linear regression analysis revealed that total ghrelin concentration was significantly associated with Apo-A1 concentration (β=0.8087; P=0.0315), and acylated ghrelin concentration was significantly associated with fasting insulin concentration (β=15.5183; P=0.011). We also observed an inverse association between unacylated ghrelin and patients’ age, and its positive association with Apo-A1.

Conclusions: Ghrelin probably influences metabolic disturbances in acromegaly. We suggest to evaluate acylated and unacylated ghrelin in all patient. It seems to be probable that changes in ghrelin forms proportions are responsible for observed disturbances.