Soy protein affects serum insulin and hepatic SREBP-1 mRNA and reduces fatty liver in rats
Soy protein affects serum insulin and hepatic SREBP-1 mRNA and reduces fatty liver in rats
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DOI：
10.1093/jn/134.3.522
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发表时间：
2004-03-01
影响因子：
4.2
通讯作者：
Tovar, AR
中科院分区：
文献类型：
--
作者：
Ascencio, C;Torres, N;Tovar, AR
研究表明，食用大豆蛋白可以降低人类和其他动物的血脂水平。此外，研究还表明，摄入大豆蛋白可以维持正常的胰岛素血症。因此，本研究的目的是确定大豆蛋白是否通过调节胰岛素水平而通过类固醇调节元件结合蛋白-1(SREBP-1)影响肝脏中脂质的合成。我们首先进行了一项短期研究，其中大鼠饲喂含有18g/100g大豆蛋白或酪蛋白的饲料10d。饲喂大豆蛋白的大鼠血清胰岛素浓度显著低于饲喂酪蛋白的大鼠，并且伴随着肝脏SREBP-1mRNA的升高，在第10天时比饲喂酪蛋白的大鼠低53%。SREBP-1mRNA的增加在平均摄入酪蛋白后30min出现，并在接下来的2小时内稳步增加。然后，我们进行了第二项研究，以评估大豆蛋白摄入150d对肝脏SREBP-1表达的长期影响。与饲喂酪蛋白的高胰岛素血症大鼠相比，长期食用大豆蛋白的大鼠维持正常的胰岛素浓度。因此，饲喂大豆蛋白饲料的大鼠的SREBP-1mRNA的表达显著低于饲喂酪蛋白的大鼠。摄入大豆蛋白还会减少脂肪酸合成酶(Fas)和苹果酸酶的表达，导致肝脏甘油三酯和胆固醇的储备量降低，而饲喂酪蛋白饮食的大鼠则会患上脂肪肝。这些数据表明，大豆蛋白通过调节血清胰岛素浓度来调节SREBP-1的表达，从而阻止脂肪肝的发展。
The consumption of soy protein was shown to reduce blood lipids in humans and other animal species. Furthermore, it was shown that the ingestion of soy protein maintains normal insulinemia. Thus, the purpose of the present study was to determine whether soy protein affects the synthesis of lipids in the liver through sterol-regulatory element binding protein-1 (SREBP-1) due to modulation of insulin levels. We first conducted a short-term study in which rats were fed a diet containing 18 g/100 g soy protein or casein for 10 d. Rats fed soy protein had significantly lower serum insulin concentrations than rats fed casein, and this response was accompanied by an elevation in hepatic SREBP-1 mRNA that was 53% lower than that in rats fed casein at d 10. The increase in SREBP-1 mRNA occurred 30 min after consumption of the casein mean, and increased steadily for the next 2 h. We then conducted a second study to assess the long-term effect of soy protein consumption for 150 d on hepatic SREBP-1 expression. Long-term consumption of soy protein maintained normal insulin concentrations compared with rats fed casein, which were hyperinsulinemic. Thus, rats fed the soy protein diet had significantly lower expression of SREBP-1 mRNA than rats fed the casein diet. Soy protein intake also reduced the expression of fatty acid synthase (FAS) and malic enzyme, leading to low hepatic lipid depots of triglycerides and cholesterol, whereas rats fed the casein diet developed fatty liver. These data suggest that soy protein regulates SREBP-1 expression by modulating serum insulin concentration, thus preventing the development of fatty liver.