) Study of Resistin and Leptin in patients with Thyroid Dysfunction

Abstract

Abstract: Background: Leptin and resistin are adipocytokines associated with body mass, insulin resistance and inflammation. Data linking adipokines with thyroid hormones are confusing. Aim: Evaluation of leptin and resistin in patients with thyroid dysfunction. Subjects and methods: 28 patients with hyperthyroidism, 26 patients with hypothyroidism and 24 age and gender matched control subjects were included in the study. BMI was calculated. Serum concentrations of TT3, FT4, TSH, resistin and leptin were measured by ELISA. Results: A higher BMI (29.4+2.1)kg/m 2 , TSH (21.7+ 2.4) Mu/L and leptin (34.9+ 2.8) ng/ml were found in the hypothyroid group compared with the hyperthyroid group BMI (23.7+2.7)kg/m 2 , TSH (0.07+ 0.03) Mu/L and leptin (9.7+ 1.8)ng/ml. The hyperthyroid group exhibited a significant increased TT3 (6.6+1.6)nmol/L, FT4 (2.6+0.1)Pmol/L and resistin (13.8+3.7)ng/ml compared with the hypothyroid group TT3 (0.3+0.1)nmol/L, FT4 (0.68+0.04)Pmol/L and resistin (6.3+3.4)ng/ml. Resistin correlated significantly and negatively with TSH (P<0.01) and BMI (P< 0.01) and positively with TT3 (P<0.01) and FT4 (P< 0.05). Leptin correlated positively with TSH (P< 0.01) and BMI (P<0.01) and negatively with TT3 (P<0.01) and FT4 (P<0.05). Factors affecting resistin level in a multivariate logistic regression analysis were sex, TT3 and FT4. Leptin is affected only by sex and TSH. The cutoff level of leptin associated with hyperthyroidism is 15.3 ng/ml with sensitivity of 100%, and specificity of 60%. Conclusion: Thyroid hormones have direct effect on resistin but not leptin. Leptin may affect the thyroid function indirectly through its central action on TSH independent of the BMI. Leptin level of 15.3 ng/ml is associated with hyperthyroidism