THE EVALUATION OF THE EFFECT OF THYROID HORMONES ON SERUM LEPTIN LEVEL

Abstract

Lept:in, the obese (ob) gene product, is a fat cell born satiety factor that is involved in the regulation of food intake and energy expenditure. The biological actions of leptin are mediated through its receptor in the hypothalamus. It is speculated that decreased production of leptin presents one of the important mechanism for the development of obesity. Plasma leptin levels have been shown to be correlated with the percentage of body fat in humans, suggesting that leptin serves as a good marker of adiposity.

Recent studies have demonstrated that leptin production is also regulated by a variety of hormones and chemicals both in vivo and in vitro, it is up regulated by insulin, glucocorticoids, or neuropeptide Y and down regulated by cAMP or thiazolidinedion derivatives.

Patients with thyroid disease usually have disturbance of body weight, food intake and thermogenesis, usually decreased body weight in hyperthyroidism, and increased body weight in hypothyroidism and so both thyroid hormones and leptin have effects on similar aspects of body homeostasis.