Endocrine Abstracts

Ghrelin is a peptide discovered in 1999 as the first natural growth hormone secretagogue. It also proved to be an essential regulator of metabolism increasing appetite, body weight and stimulating peristalsis. Thyroid plays an important role in the maintenance of energy balance. Thus, correlation between ghrelin and thyroid function is worth consideration. Previous studies suggested, that ghrelin production is increased in hypothyroidism and decreased in hyperthyroism. However, since ghrelin production depends on many factors, including individual features, studies conducted on different groups of patients may not be accurate.

We evaluated plasma ghrelin concentrations in the same patients in hyperthyroid, hypothyroid and euthyroid phase, assuming, that such assessment would be the most relevant analysis of plasma ghrelin changes in thyroid disorders.

The study group was selected from the patients with hyperthyroidism treated with radioiodine and followed-up after therapy. Ghrelin level was firstly assessed in hyperthyroid phase. In 12 patients, who developed hypothyroidism after radioiodine, the second measurement was performed. The third analysis was made in euthyroid phase after L-thyroxine replacement therapy. Blood samples were collected from antecubital vein at fast. Plasma ghrelin was measured with a commercial radioimmunoassay.

The study revealed, that in 11 patients ghrelin concentration was the lowest in hyperthyroidism, the highest in hypothyroid phase and reached medium value in euthyroidism. Mean ghrelin levels in all 12 patients were also decreased in hyperthyroidism (TSH 0.006±0.002 uIU/ml; ghrelin 144.47±84.15 pg/ml) and increased in hypothyroidism (TSH 62±29.63 uIU/ml; ghrelin 320.95±190.16 pg/ml) in comparison to euthyroid phase (TSH 1.53±0.81 uIU/ml; ghrelin 216.16±111.61 pg/ml).

Plasma ghrelin changes may indicate its compensatory role in thyroid dysfunction. Low ghrelin level decreases metabolic rate in hyperthyroid patients and high ghrelin concentration leads to appropriate use of energy in hypothyroidism.

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.