DIETARY FIBER AND FAT IN BILE ACID EXCRETION

结肠癌是最常见的癌症之一。流行病学 有证据表明，它的起源本质上是环境的，而且 饮食可能对其发病率有很大影响。膳食纤维一直是 饮食脂肪可能会促进结肠癌，但这可能是一种保护作用。这个 这两种饮食成分的作用可能通过共同的 点-粪便胆汁酸。有证据表明粪便胆汁酸是肿瘤 促进剂。拟议的项目旨在调查 从谷类和豆类以及脂肪中提取的膳食纤维的作用 粪便胆汁酸(浓度和总排泄量)和胆汁 酸池大小。将进行四次喂养试验。在试验1-3中， 大鼠将被喂以无纤维的食物或含有丰富纤维的食物 分数。在试验1中，纤维来源将是硬红的麸皮 春小麦、硬质小麦和柔软的白色小麦。在试验2中，燕麦、黑麦、 大麦和玉米将被喂养。在试验3中，来自平托的富含纤维的部分， 海军，四季豆将被喂食。在试验4中，纯化的纤维 纤维素和木质素以及纯化的可溶性膳食纤维组分 并将喂食纯化的不溶性膳食纤维部分。总共有4个 试验中，所描述的每种饮食都将在低水平和高水平(5%比20%)的水平上喂养 脂肪。喂养5周后，将采集粪便样本5周。 用高效毛细管电泳法测定胆汁酸 酸化乙醇萃取液相色谱分离 用C18 9月-PAKS进行纯化。然后这些动物将被杀死，而 取胃、肝、小肠、盲肠和结肠，胆汁酸 提取并化验胆汁酸以确定水池大小。此外, 结肠1α-脱羟基酶活性将用 放射测定法。结果将通过双向方差分析进行分析， 使用Bonferroni t检验进行多重比较。

Colon cancer is one of the most common forms of cancer. Epidemiological evidence indicates that its genesis is environmental in nature and that diet may greatly influence its incidence. Dietary fiber has been implicated as protective whereas dietary fat may promote colon cancer. The effect of these two dietary components may be mediated through a common point - fecal bile acids. Evidence exists that fecal bile acids are tumor promoting agents. The proposed project is designed to investigate the effect of dietary fiber, derived from cereals and legumes, as well as fat on fecal bile acids (concentration and total excretion), and on the bile acid pool size. Four feeding trials will be conducted. In trials 1-3, rats will be fed a fiber-free diet or diets containing a fiber rich fraction. In trial 1 the fiber sources will be the brans of hard red spring, durum, and soft white wheat. In trial 2 the brans of oats, rye, barley and corn will be fed. In trial 3 fiber-rich fractions from pinto, navy, and kidney beans will be fed. In trial 4 the purified fibers cellulose and lignin as well as a purified soluble dietary fiber fraction and a purified insoluble dietary fiber fraction will be fed. In all 4 trials, each diet described will be fed at a low and high (5 vs. 20%) level of fat. After 5 weeks of feeding, fecal samples will be collected for 5 days and the pooled sample assayed for bile acids by high performance liquid chromatography after extraction with acidified ethanol and partial purification with C18 Sep-Paks. The animals will then be killed and the stomach, liver, small intestine, cecum, and colon taken, the bile acids extracted and assayed for bile acids to determine pool size. In addition, colonic 1 alpha-dehydroxylase activity will be determined using a radioassay. Results will be analyzed by two-way analysis of variance, with multiple comparisons to be made using the Bonferroni t-test.