Endocrine Abstracts

Introduction: Irisin is a recently reported adipo-myokine. To date, many researchers underline its significant influence on the body metabolism and thermogenesis. Secreted by muscle and adipose tissue irisin promotes a program of subcutaneous white adipose tissue ‘browning’. As a result, heat production and general energy expenditure raise. Irisin is considered to be a potential mediator of the health-promoting role of physical exercises. Its possible compensatory role in metabolic regulation was also suggested.

Aim: The main goal of the project is to asses serum irisin concentration in patients with thyroid function impairment and its correlation with creatine kinase (CK) level.

Methods: A studied group consisted of 20 patients newly diagnosed with thyroid function impairement at our department. All subjects underwent routine clinical examination, laboratory tests (irisin, thyroid-stimulating hormone – TSH, free thyroxin – FT4 and triiodothyronine – FT3, and CK concentrations), thyroid ultrasound examination. The associations between irisin, TSH, free thyroid hormones, creatine kinase were analyzed statistically. Furthermore, the difference between irisin serum concentration in hypothyroid and hyperthyroid patients was evaluated.

Results: The negative correlation between the irisin and TSH level was demonstrated (r=−0.4924, P=0.023), as well as positive correlation between the irisin and FT4 level (r=0.4833, P=0.036). CK level was negatively correlated with irisin, FT4 and FT3 concentrations (r=−0.7272, P=0,014; r=−0.9636, P≤0.0001; r=−0.8838, P=0.0.0007 respectively). The mean serum irisin level was lower in hypothyroid than hyperthyroid patients, at the border of statistical significance (P=0.0726).

Conclusions: Obtained results suggest the influence of thyrometabolic state on irisin concentration; lower irisin level was found in patients with hypothyroidism. This might be explained with muscle destruction, demonstrating with high CK level.