Evaluation of Growth Differentiation Factor-15 in Non-Diabetic Hypothyroid Patients with Normal Insulin Sensitivity and Maintained on Oral Thyroxin Therapy

Background Hypothyroidism is a common disorder of the endocrine system in which the thyroid gland does not produce enough thyroid hormone. It has been associated with many systemic disorders including insulin resistance due to various mechanisms. In the other hand insulin resistance is associated with Growth differentiation factor 15, that has a role in regulating inflammatory and apoptotic pathways in injured tissues and during disease processes. Objective This study was designed to evaluate growth differentiation factor-15 in non-diabetic hypothyroid patients with normal insulin sensitivity. Subjects and Methods The case-control study comprised of 85 subjects as a total, among them 33 hypothyroid patients aging between 40 to 60 years and 52 apparently healthy subjects of comparable age, weight, height, and sex. Exclusion criteria were cigarettes smoking, pregnancy, cardiovascular, kidney, liver, respiratory diseases, diabetes mellitus, insulin resistance, malignancy, and other autoimmune diseases like systemic lupus erythematosus and rheumatoid arthritis. Fasting blood specimens were obtained for testing serum levels of growth differentiation factor-15, thyroid stimulating hormone, thyroxin, insulin, glucose. While quantitative insulin sensitivity check index was calculated. Results The results showed that, growth differentiation factor-15 levels were elevated in patients group as compared with that of control subjects group. Only in hypothyroid patients group, there was a positive correlation between growth differentiation factor-15 and serum thyroid stimulating hormone. Conclusion GDF-15 was elevated even with normal insulin sensitivity in non-diabetic hypothyroid patients.