Endocrine Abstracts

Glucagon-like peptide-1 (GLP-1) is an increatin hormon with various glucoregulatory effects, and exenatide is a GLP-1 receptor agonist used in the management of type 2 diabetes mellitus. C cell hypertrophy was seen in animals treated with GLP-1 receptor agonists, but the effects of GLP-1 agonists on C-cell proliferation or neoplasia in humans have not been documented formerly. The aim of this study was to evaluate the impact of exenatide on structural and functional features of the thyroid in patients with T2DM treated with exenatide. Fourty-eight patients with T2DM were included in the study. 5 μg exenatide was started to all patients twice daily.After 4 weeks the dose was increased to 10 μg twice daily.Four patients who had severe vomiting were excluded. Serum free triiodothyronine (T3), free thyroxine (T4), thyrotropin (TSH), anti-thyroid peroxidase (anti-TPO), anti-thyroglobulin (anti-Tg), carcino-embryonic antigen (CEA) and calcitonin were measured and thyroid ultrasonography was performed before the treatment was started and after 6th month. Fourty-one women and three men were included in the analysis with a mean age of 47.84±7.37 years. The laboratory parameters and thyroid ultrasonographic features are summarized in the table. A significantly statistically decrease was achieved in TSH (P<0.001) and thyroid volume (P:0.047). The statistical analysis was performed with 32 patients who were not using levothyroxine at the beginning, and TSH decrease was still statistically significant (P:0.022), whereas the reduction of the thyroid volume lost its significant difference (P:0.130). In conclusion, our study showed no difference in serum CEA and calcitonin level after 6 months of exenatide therapy, whereas a reduction in the thyroid volume was achieved for the first time in the literature.