Kinzig Kimberly P, Hargrave Sara L, Hyun Jayson, Moran Timothy H
Purdue University, Department of Psychological Sciences, United States.
Physiol Behav. 2007 Oct 22;92(3):454-60. doi: 10.1016/j.physbeh.2007.04.019. Epub 2007 Apr 22.
Diets high in fat or protein and extremely low in carbohydrate are frequently reported to result in weight loss in humans. We previously reported that rats maintained on a low-carbohydrate-high fat diet (LC-HF) consumed similar kcals/day as chow (CH)-fed rats and did not differ in body weight after 7 weeks. LC-HF rats had a 45% decrease in POMC expression in the ARC, decreased plasma insulin, and increased plasma leptin and ghrelin. In the present study we assessed the effects of a low-carbohydrate-high-protein diet (HP: 30% fat, 65% protein, and 5% CHO) on body weight, caloric intake, plasma hormone levels and hypothalamic gene expression. Male rats (n=16) were maintained on CH or HP for 4 weeks. HP rats gained significantly less weight than CH rats (73.4+/-9.4 and 125.0+/-8.2 g) and consumed significantly less kcals/day (94.8+/-1.5 and 123.6+/-1.1). Insulin was significantly reduced in HP rats (HP: 1.8+/-0.6 vs. CH: 4.12+/-0.8 ng/ml), there were no differences between groups in plasma leptin and plasma ghrelin was significantly elevated in HP rats (HP: 127.5+/-45 vs. CH: 76.9+/-8 pg/ml). Maintenance on HP resulted in significantly increased ARC POMC (HP: 121+/-10.0 vs. 100+/-5.9) and DMH NPY (HP: 297+/-82.1 vs. CH: 100+/-37.7) expression compared to CH controls. These data suggest that the macronutrient content of diets differentially influences hypothalamic gene expression in ways that can affect overall intake.
据报道，高脂肪或高蛋白且碳水化合物含量极低的饮食常常会导致人体体重减轻。我们之前报道过，以低碳水化合物高脂肪饮食（LC-HF）喂养的大鼠每天摄入的千卡热量与喂食普通饲料（CH）的大鼠相似，且7周后体重并无差异。LC-HF大鼠弓状核中阿黑皮素原（POMC）表达下降45%，血浆胰岛素水平降低，血浆瘦素和胃饥饿素水平升高。在本研究中，我们评估了低碳水化合物高蛋白饮食（HP：30%脂肪、65%蛋白质和5%碳水化合物）对体重、热量摄入、血浆激素水平和下丘脑基因表达的影响。雄性大鼠（n = 16）分别以CH或HP饮食喂养4周。HP组大鼠体重增加显著少于CH组（分别为73.4±9.4克和125.0±8.2克），且每天摄入的千卡热量显著更少（分别为94.8±1.5和123.6±1.1）。HP组大鼠的胰岛素水平显著降低（HP组：1.8±0.6 vs. CH组：4.12±0.8纳克/毫升），两组血浆瘦素水平无差异，而HP组大鼠的血浆胃饥饿素显著升高（HP组：127.5±45 vs. CH组：76.9±8皮克/毫升）。与CH对照组相比，HP饮食喂养导致弓状核POMC（HP组：121±10.0 vs. 100±5.9）和背内侧下丘脑神经肽Y（NPY）（HP组：297±82.1 vs. CH组：100±37.7）表达显著增加。这些数据表明，饮食中的常量营养素含量会以影响总体摄入量的方式对下丘脑基因表达产生不同影响。
