Endocrine Abstracts

Ghrelin has been considered one of the factors that might contribute to the development of pituitary somatotropinoma.

The aim of our study was to assess whether serum concentrations of ghrelin differ in patients with acromegaly treated with surgery or/and long-acting octreotide (LAO) and also to evaluate the presence of ghrelin mRNA in tissues of somatotroph adenomas. The appoval of Ethical Committee to perform the study was obtained.

Materials: Serum ghrelin was measured with the use of radioimmunoassay RIA (Phoenix Pharmaceuticals) in 42 acromegalic patients and in 18 healthy control subjects. Acromegalic patients were divided into groups according to the treatment that had been administered: 1) surgery /−/, LAO/+/ 2) surgery /+/, LAO /+/ 3) surgery /−/, LAO /−/ 4) surgery /+/, LAO /−/. Human pituitary somatotroph adenoma tissues were obtained at transsphenoidal surgery from 3 acromegalic patients with macroadenomas and studied for ghrelin mRNA expression. Before surgery patients received long acting octreotide at doses 20 mg, 30 mg, 30 mg at 30 days intervals. The reverse transcription and real-time PCR were performed according to Korbonits et al. method.

Results: The difference between mean ghrelin level in the healthy subjects and acromegalic patients was not statistically significant (P=0.08), neither between patients who had and who had not undergone surgery (P=0.1). Patients treated with somatostatin analogue (Sandostatin LAR) had serum ghrelin levels significantly lower than patients who had undergone surgery and than healthy subjects (p=0.001). Ghrelin mRNA was not detected in any examined tissues.

Conclusions: Ghrelin concentrations were significantly lower in acromegalic patients who had been receiving long acting somatostatin analogue treatment; the absence of ghrelin mRNA might be due to the treatment with somatostatin analogue administered preoperatively, which could have suppressed the ghrelin gene transcription.