Incretin levels in patients with hypothyroidism and the evaluation of incretin levels alterations with treatment

Abstract

Abstract Background Incretin hormones may influence the effects of thyroid hormones on insulin secretion, insulin resistance, and glucose metabolism. Thyroid hormones regulate insulin secretion, and the risk of diabetes was found to be associated with thyroid hormones. Objectives To determine whether incretin hormones influence the effects of thyroid hormones on insulin resistance and glucose metabolism. Methods A total of 26 patients were included in 2 groups consisting of 13 patients with hypothyroidism and 13 healthy controls. Levels of glucose, insulin, glucagon-like peptide 1 (GLP-1), and gastric inhibitory polypeptide (GIP) levels were measured in 0, 30, 60, 90, and 120th min during the oral glucose tolerance test in the control group and before and after thyroxine treatment in the hypothyroid group. Results In the hypothyroid group, waist circumference decreased after the euthyroid state was achieved (P = 0.026). No statistically significant differences were detected in the GLP-1 and GIP levels at baseline and 30, 60, 90, and 120 min between the hypothyroidism and control groups or after ensuring the euthyroid state in patients with hypothyroidism. Peak GLP-1 levels were observed at 30 min in the control group, whereas peak GLP-1 and GIP levels were detected at 90 min in the hypothyroidism group. After achieving the euthyroid state, peak GLP-1 and GIP levels were detected at 30 min as well. Conclusion In patients with hypothyroidism, the incretin hormones, especially the peak response of the incretin system, are significantly affected. Significant changes were observed in the incretin system by correcting hypothyroidism.