Endocrine Abstracts

Objective: Thyroid dysfunctions have various effects on glucose and lipid metabolism. Adiponectin (ADP) is an adipokine decreased in obesity and insulin resistance. In this study, we aimed to investigate the role for ADP in thyroid dysfunction related changes in glucose and lipid metabolism.

Methods: Newly diagnosed overt hypothyroid (n=20) and thyrotoxic (n=23) adult patients with a body mass index (BMI)<30 kg/m² were included. Patients with a known insulin resistance related disease and chronic disease were excluded. Patients were matched with healthy controls (n=20) according to age, sex and BMI. Thyrotropin (TSH), free T₃, free T₄, fasting plasma glucose (FPG), insulin, HOMA-IR, HOMA-bcf, lipid profile and ADP levels were evaluated at the time of diagnosis and after the restoration of euthyroidism.

Results: Hypothyroid patients had significantly lower FPG and higher HOMA-bcf compared to thyrotoxic patients (P<0.001 and P=0.15, respectively). Fasting plasma insulin and HOMA-IR were similar in groups. Restoration of euthyroidism in hypothyroidism and thyrotoxicosis resulted in increased and decreased FPG, respectively (P=0.002 and P=0.001, respectively), but no significant change in fasting plasma insulin, HOMA-IR and HOMA-bcf. Basal plasma ADP levels were 14.55±8.4, 13.79±9.13 and 11.68±6.0 μg/ml in hypothyroid, thyrotoxic and healthy controls, respectively (P=0.503). Adiponectin decreased significantly in hypothyroidism (P=0.047), while did not change in thyrotoxicosis (P=0.770) with achievement of euthyroidism. There was no correlation between basal ADP and TSH, thyroid functions, FPG and insulin, HOMA-IR, HOMA-bcf and lipid parameters in hypothyroid and thyrotoxic patients.

Conclusion: We showed that FPG increased in hypothyroid and decreased in thyrotoxic patients with restoration of euthyroidism. HOMA-IR and HOMA-bcf did not change in thyroid dysfunctions before and after restoration of euthyroidism. Decreased ADP in hypothyroidism after achievement of euthyroidism may be related with increased FPG in these patients, however lack of change in thyrotoxicosis indicates need for further studies with larger sample sizes.