Serum leptin level in hypothyroid males.

OBJECTIVE

To determine the correlation of serum leptin with thyroid hormones in primary hypothyroid male patients and euthyroid lean and obese control subjects.

DESIGN

Comparative study.

PLACE AND DURATION OF STUDY

Atomic Energy Medical Center, JPMC, Karachi, from 2001 to 2003.

SUBJECTS AND METHODS

In this study, three male groups were included. Those were 21 newly-diagnosed, untreated hypothyroid male patients (BMI, 25.12+/-2.31), 24 age and BMI matched euthyroid lean male subjects (BMI, 24.01+/-1.97) and 27 euthyroid obese male subjects (BMI, 33.02+/-2.67). Patients were selected from the thyroid OPD of Atomic Energy Medical Centre, JPMC, Karachi, while healthy, age and BMI matched euthyroid (lean and obese) were selected from general population after checking their thyroid profile. Patients and control subjects suffering from diabetes or other endocrinal diseases and taking thyroxin or steroid were excluded from the study. Serum leptin was measured by ELISA and FT4, FT3 and TSH were measured by radioimmunoassay (RIA), triacylglycerol (TG), total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) by kit method, low density lipoprotein cholesterol (LDL-C) was calculated by the Friedwald s formula, and fasting blood sugar (FBS) by glucose oxidase method.

RESULTS

The mean +/- SEM values of leptin in male hypothyroid patients were 10.71+/-2.5 ng/ml, 8.27+/-1.91 in control group and 21.34+/-3.4 ng/ml in obese group, respectively. No significant difference was found in serum leptin levels between hypothyroid patients and their age, BMI matched control group, while obese control group had significantly higher values of leptin (<0.05). There was no significant correlation of leptin found with T4, T3, and TSH in hypothyroid patients and lean and obese control subjects. Triacylglycerol (TG, p < 0.005), total cholesterol (TC, p < 0.005) and low density lipoprotein cholesterol (LDL-C, p < 0.05) were significantly higher in hypothyroid patients as compared to control groups. This study observed that serum leptin level was significantly correlated with the BMI (r = 0.732, p < 0.005, r = 0.783, p < 0.005, r = 0.653, p < 0.005), in normal lean, obese and hypothyroid male patients respectively.

CONCLUSION

The results of this study suggest that there is no correlation between serum leptin and thyroid hormones in hypothyroid patients as well as in euthyroid subjects. Serum leptin is directly related with BMI.