Milanski Maristela, Souza Kleber L A, Reis Sílvia R L, Feres Naoel H, de Souza Letícia M I, Arantes Vanessa C, Carneiro Everardo M, Boschero Antonio C, Reis Marise A B, Latorraca Márcia Q
Secretaria de Estado de Educação e Cultura, Mato Grosso, Brazil.
Nutrition. 2009 Jul-Aug;25(7-8):774-81. doi: 10.1016/j.nut.2008.12.003. Epub 2009 Feb 28.
The present study evaluated the effect of nutritional recovery with a soybean diet on the gene and protein expressions and protein phosphorylation of several enzymes and transcription factors involved in hepatic lipid metabolism.
Rats from mothers fed with 17% or 6% protein (casein) during pregnancy and lactation were maintained with a 17% casein (CC and LC groups) or soybean (CS and LS groups) diet and with a 6% casein (LL group) diet until 90 d of life.
The soybean diet enhanced serum insulin levels but decreased body and liver weights and hepatic lipid and glycogen concentrations. Liver peroxisome proliferator receptor-alpha mRNA abundance was higher in the LS and CS groups than in the LC and CC groups, but the protein content was similar in all groups. Hepatic acetyl-coenzyme A carboxylase (ACC)-alpha and ACCbeta mRNA expression was markedly lower in the LS and CS rats than in the LC and CC rats. ACC protein expression was lower in the CS group than in the CC, LC, and LS groups. Phospho-[Ser(79)]2-ACC content was similar in the CS, LC, and LS groups and lower than the CC group. In the CS rats this reduction paralleled the decrease in total ACC protein. Messenger RNA and protein expression of sterol regulatory element-binding protein 1c, adenosine monophosphate-activated protein kinase, and phospho-[Thr(172)]-adenosine monophosphate-activated protein kinase was not modified by the soybean diet.
Thus, the soybean diet reduced the liver lipid concentration through downregulation of the ACC gene and protein expressions rather than by phosphorylation status, which possibly resulted in decreased lipogenesis and increased beta-oxidation.
本研究评估了大豆饮食营养恢复对肝脏脂质代谢中几种酶和转录因子的基因与蛋白表达及蛋白磷酸化的影响。
将孕期和哺乳期母鼠分别喂食17%或6%蛋白质（酪蛋白）的大鼠，维持其食用17%酪蛋白（CC组和LC组）或大豆（CS组和LS组）饮食以及6%酪蛋白（LL组）饮食直至90日龄。
大豆饮食提高了血清胰岛素水平，但降低了体重、肝脏重量以及肝脏脂质和糖原浓度。LS组和CS组肝脏过氧化物酶体增殖物激活受体α mRNA丰度高于LC组和CC组，但所有组的蛋白质含量相似。LS组和CS组肝脏乙酰辅酶A羧化酶（ACC）α和ACCβ mRNA表达明显低于LC组和CC组。CS组ACC蛋白表达低于CC组、LC组和LS组。CS组、LC组和LS组磷酸化-[丝氨酸（79）]2-ACC含量相似且低于CC组。在CS组大鼠中，这种降低与总ACC蛋白的减少平行。大豆饮食未改变固醇调节元件结合蛋白1c、腺苷单磷酸激活蛋白激酶以及磷酸化-[苏氨酸（172）]-腺苷单磷酸激活蛋白激酶的mRNA和蛋白表达。
因此，大豆饮食通过下调ACC基因和蛋白表达而非磷酸化状态降低了肝脏脂质浓度，这可能导致脂肪生成减少和β氧化增加。
