ABSTRACT
Leptin and Ghrelin are hormones that have been discovered in the last decade and were shown to be involved in appetite and metabolism regulation and body weight. Thyroid hormones are also involved in general metabolism and changes in their circulating levels bring about changes in appetite and body weight. Results of animal and human studies regarding Leptin level and its relation to thyroid hormones are opposing each other, and there is no data about Ghrelin level in thyroid malfunction. To determine the relation between thyroid function and circulating levels of Ghrelin and Leptin, we evaluated serum concentration of these hormones in patients with untreated thyroid malfunction. Thirty hyperthyroid and 30 hypothyroid females that were aged between 14-52 years and 30 healthy females with the same age range [control group] were randomly selected. From each participant 5 ml of fasting blood was collected and after processing, serum levels of T[4], T[3], T[3]-uptake, TSH, Leptin and Ghrelin were evaluated by radio-immunoassay or enzyme-link immunoassay methods. Evaluated results showed that neither Ghrelin nor Leptin levels show significant change in patients with thyroid malfunction. But there was a positive significant correlation between Leptin level and BMI of all participants [r=0.41, P<0.01]. In addition, there were negative significant correlations between Ghrelin and thyroid hormones [r=0.27, P<0.05].
The present results show that Leptin variation is due to BMI. Furthermore, negative and weak correlation between thyroid hormones and Ghrelin may indicate that increase in appetite of hyperthyroid patients and its decrease in hypothyroid patients are not due to circulating level of Ghrelin