Baum Jamie I, Layman Donald K, Freund Gregory G, Rahn Kristen A, Nakamura Manabu T, Yudell Barbara E
Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
J Nutr. 2006 Jul;136(7):1855-61. doi: 10.1093/jn/136.7.1855.
The dietary reference intakes (DRIs) established an acceptable macronutrient distribution range (AMDR); however, few studies have evaluated differences in metabolic regulations across the DRI range. This study examined differences in glycemic regulations associated with specific ratios of carbohydrate and protein. Male rats ( approximately 200 g) were fed either a high-carbohydrate diet (CHO group: 60% of energy as carbohydrates, 12% protein, 28% fat) or a reduced-carbohydrate diet [PRO (protein) group: 42% carbohydrates, 30% protein, 28% fat]. Rats consumed 3 meals/d with energy distributed as 16, 42, and 42%. On d 25, blood and tissues were obtained after 12 h of food deprivation and at 30 and 90 min after the first meal. Before the meal, the CHO group had lower plasma glucose and insulin, reduced liver glycogen, lower expression of hepatic phosphoenolpyruvate carboxylase (PEPCK), and increased fatty acid synthase (FAS) in adipose tissue. After the meal, the CHO group had greater increases in plasma glucose and insulin, producing increased skeletal muscle phosphatidylinositol 3-kinase (PI3-kinase) activity, glucose uptake, and glycogen content, and increased adipose PI3-kinase activity, glucose uptake, and FAS. In contrast, the PRO group had limited postprandial changes in plasma glucose and insulin with reduced muscle PI3-kinase activity and glucose uptake, and no postprandial changes in adipose PI3-kinase activity or FAS. This study demonstrates that changes in carbohydrate and protein intakes within the AMDR produce fundamental shifts in glycemic regulation from high-CHO diets that require insulin-mediated peripheral glucose disposal to high-PRO diets that increase hepatic regulation of glucose appearance into the blood.
膳食参考摄入量（DRIs）确立了可接受的宏量营养素分布范围（AMDR）；然而，很少有研究评估在DRIs范围内代谢调节的差异。本研究考察了与碳水化合物和蛋白质特定比例相关的血糖调节差异。给雄性大鼠（约200克）喂食高碳水化合物饮食（CHO组：能量的60%为碳水化合物，12%为蛋白质，28%为脂肪）或低碳水化合物饮食[PRO（蛋白质）组：42%碳水化合物，30%蛋白质，28%脂肪]。大鼠每天进食3餐，能量分配为16%、42%和42%。在第25天，禁食12小时后以及第一餐后30分钟和90分钟采集血液和组织。进食前，CHO组的血浆葡萄糖和胰岛素水平较低，肝糖原减少，肝磷酸烯醇式丙酮酸羧化酶（PEPCK）表达降低，脂肪组织中脂肪酸合酶（FAS）增加。进食后，CHO组的血浆葡萄糖和胰岛素升高幅度更大，导致骨骼肌磷脂酰肌醇3激酶（PI3激酶）活性、葡萄糖摄取和糖原含量增加，脂肪组织PI3激酶活性、葡萄糖摄取和FAS增加。相比之下，PRO组餐后血浆葡萄糖和胰岛素变化有限，肌肉PI3激酶活性和葡萄糖摄取降低，脂肪组织PI3激酶活性或FAS无餐后变化。本研究表明，在AMDR范围内碳水化合物和蛋白质摄入量的变化会导致血糖调节发生根本性转变，从需要胰岛素介导外周葡萄糖处置的高CHO饮食转变为增加肝脏对血液中葡萄糖出现调节的高PRO饮食。
