The Investigation Of Serum Leptin And It's Relation To PTA In Infants With Congenital Hypothyroidism

Objective To study the changes of serum leptin concentration in infants with congenital hypothyroidism(CH) before and after replacement therapy with L-thyroxine(L-T4),and it's relation to pituitary thyroid axis (PTA).Method The serum leptin concentration was measured by radioimmunoassays(RIA) and serum free triiodothyronine (FT3 X free thyroxine(FT4), thyroid stimulating hormone(TSH) concentration was measured by electrochemiluminoimmunoassay(ECLIA)in 23 infants(11 males, 12 females) with CH before and after successful L-thyroxine(L-T4) replacement therapy(thyroid function was completely restored),and 46 normal controls that age, sex, BMI matched with CH patients respectively. Statistical analyses were carried out with SPSS 10.0 for windows using simple correlation, the t-test for paired data. Data are presented as means S.E.M.Results Surum leptin concentration was correlated with BMI(n=92, =0.48, P<0.001 )in infants and had a positive correlation withFT4(n=46, =0.43, p<0.01) , a negative correlation with TSH(n=46,Y =-0.36, p<0.02) In CH group,but had a negative correlation with FT4 (n=46, y =-0.36, p<0.02)in normal control group. The range of surum leptin concentration changes in CH group were significantly higher than normal control group (P<0.05).Conclusion These results suggest that surum leptin was affected by FT4 and TSH in CH, Surum leptin concentration had a positive correlation with FT4 ., a negative correlation with TSH In CH group ,and had a positive correlation with BMI in infants, detecting surum leptin may be a second examination method to instructe the treatment of CH in the future .