T3 and Triac inhibit leptin secretion and expression in brown and white rat adipocytes.
T3 and Triac inhibit leptin secretion and expression in brown and white rat adipocytes.
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DOI：
10.1016/j.bbalip.2004.01.007
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发表时间：
2004-06
期刊：
影响因子：
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通讯作者：
G. Medina-Gómez;R. Calvo;M. Obregon
中科院分区：
文献类型：
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作者：
G. Medina-Gómez;R. Calvo;M. Obregon
瘦素能调节食欲，抑制食物摄入，似乎还能增加能量消耗。我们研究了三碘甲状腺乙酸（Triac）对瘦素分泌和mRNA表达的影响，三碘甲状腺乙酸是T3的代谢物，似乎比T3更产热。增加Triac和T3浓度处理大鼠白色和棕色脂肪细胞原代培养物。还测试了不同类型的血清和胰岛素浓度的影响。血清抑制瘦素分泌和mRNA表达。Triac和T3也能明显抑制瘦素的分泌，并呈剂量依赖性，且具有相似的效价。在去甲肾上腺素（NE）存在时，Triac和T3具有相似的抑制作用，但在白色脂肪细胞中几乎完全抑制。在mRNA水平上发现了类似的结果，其中Triac和T3具有相似的抑制效力，无论是单独使用还是与NE一起使用。我们还发现胰岛素诱导瘦素分泌的剂量和时间依赖性增加，白色和棕色脂肪细胞分别在0.5和3 nM胰岛素时达到最大水平。白色脂肪细胞的瘦素分泌量高于棕色脂肪细胞。在瘦素分泌增加之前，瘦素mRNA增加。总之，这些数据首次证明Triac与T3和血清一样，抑制白色和棕色脂肪细胞中瘦素的分泌和表达，而胰岛素具有相反的作用。
Leptin regulates appetite, inhibits food intake, and seems to increase energy expenditure. We investigated the effect of triiodothyroacetic acid (Triac), a metabolite of T3, which seems to be more thermogenic than T3, on leptin secretion and mRNA expression. Rat primary cultures of white and brown adipocytes were treated with increasing concentrations of Triac and T3. The effect of different types of serum and insulin concentrations was also tested. Serum inhibited leptin secretion and mRNA expression. Leptin secretion was also clearly inhibited by Triac and T3 in a dose-dependent manner and with similar potency. In the presence of norepinephrine (NE), Triac and T3 had a similar inhibitory effect, but the inhibition was almost complete in white adipocytes. Parallel results were found at the mRNA level, where Triac and T3 had similar inhibitory potency, both alone and with NE. We also show that insulin induced dose- and time-dependent increases in leptin secretion, reaching maximum levels at 0.5 and 3 nM insulin for white and brown adipocytes, respectively. Leptin secretion was higher in white than in brown adipocytes. The increases in leptin secretion were preceded by increases in leptin mRNA. In conclusion, these data demonstrate for the first time that Triac, like T3 and serum, inhibits leptin secretion and expression in white and brown adipocytes, whereas insulin has the opposite effect.