Enhanced expression of uncoupling protein 2 gene in rat white adipose tissue and skeletal muscle following chronic treatment with thyroid hormone

Evidence is rapidly emerging which suggests that uncoupling protein 2 (UCP2), by virtue of its ubiquitous expression, may be important far determining basal metabolic rate, To assess the functional modulation of UCP2 gene expression in relation to body weight control,,ve examined the effects of hyperthyroid state induced by chronic treatment with triiodothyronine (T-3) on UCP2 mRNA expression in male rats, Daily subcutaneous injection of T-3 (37 pmol/100 g body weight) for 7 days increased UCP2 mRNA expression in brown adipose tissue (BAT), white adipose tissue (WAT) and the soleus muscle 1.6-, 1.6- and 1.7-fold compared to the controls, respectively, and increased UCP1 mRNA expression in BAT 1.2-fold. In contrast, the same treatment with T-3 decreased both ob mRNA expression in WAT and plasma leptin level 0.5-fold for each, The present results suggest that T-3 may directly increase UCP2 expression independently of leptin action. (C) 1997 Federation of European Biochemical Societies.