Effect of thyroid hormones on α cell function in type 2 diabetic patients

Abstract

Objective To investigate the effect of thyroid hormone on α cell function in type 2 diabetic patients with normal thyroid function. Methods Three hundred and seventy-eight type 2 diabetic patients with normal thyroid function were recruited, and they were divided into three groups according to the levels of serum free three iodine thyronine(FT3). The clinical and biochemical parameters, thyroid hormone levels, fasting and postprandial insulin and glucagon levels were measured. Results The HbA1C(9.23%±2.48%, 8.48%±1.84%, 7.91%±1.51% respectively)were significantly different among tertile groups of FT3. With the increase of FT3 level, the glucagon levels at each time point, areas under the curve of glucose(AUCG)and glucagon, glucagon over insulin ratio(R/I)all decreased significantly(all P<0.05). Multivariate linear regression analysis demonstrated that the fasting glucagon levels were negatively associated with high density lipoprotein-cholesterol and FT3(β=-0.162, 95%CI -17.42--4.56, P<0.01; and β=-0.129, 95%CI -6.42--0.99, P<0.01 respectively), and positively associated with lnAUCG(β=0.398, 95%CI 29.69-48.31, P<0.01). Conclusion FT3 levels were negatively associated with glucagon levels in type 2 diabetic patients with normal thyroid function. The normal physiological concentration of FT3 may reduce glucagon levels in patients with type 2 diabetes mellitus, resulting in a decrease in blood glucose level. (Chin J Endocrinol Metab, 2015, 31: 951-955) Key words: Glucagon; Thyroid hormones; Diabetes mellitus, type 2