Leptin acute modulation of the 5'-deiodinase activities in hypothalamus, pituitary and brown adipose tissue of fed rats.

摘要: Leptin and thyroid hormones (TH) have the ability to increase energy expenditure. Biological effects of TH are dependent on thyroxine (T4) triiodothyronine (T3) conversion by deiodinase type 1 (D1) 2 (D2). has been shown stimulate hypothalamus-pituitary-thyroid axis and, also, modulate 5'-deiodinases in different tissues, depending energetic status animals. Here, we examined acute leptin hypothalamic, pituitary BAT D2 D1 activities. Male fed rats received a single subcutaneous injection saline or (8 microg/100 g BW) sacrificed hours later. promoted an important decrease hypothalamic (55% reduction, p <0.001) with no changes D2, concomitance 2-fold rise serum TSH, suggesting that acted at hypothalamus order TRH-TSH axis. In addition, was decreased 25% (p<0.05). contrast, showed (p<0.001), indicating that, as demonstrated before for liver D1, enzyme is also acutely up-regulated leptin. Serum concentrations insulin leptin-injected animals remained unchanged. Regulation directing local T3 production, mechanism which may alter functions.