Enhancement of mammary carcinogenesis by high levels of dietary fat: a phenomenon dependent on ad libitum feeding.
Enhancement of mammary carcinogenesis by high levels of dietary fat: a phenomenon dependent on ad libitum feeding.
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高水平的膳食脂肪增强乳腺癌的发生：一种依赖于随意进食的现象。
DOI：
10.1093/jnci/82.20.1615
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Welsch,MA
中科院分区：
文献类型：
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作者：
Welsch,CW;House,JL;Herr,BL;Eliasberg,SJ;Welsch,MA
用单次静脉内剂量的7，12-二甲基苯并蒽（DMBA）处理55日龄雌性Sprague-Dawley大鼠，每只2 mg/100 g体重。在60日龄时，将大鼠分为4个饮食组（41-42只/组）：I，5%玉米油饮食，自由采食; II，20%玉米油饮食，自由采食; III，5%玉米油饮食，比I组少12%; IV，20%玉米油饮食，比II组少12%。5%和20%玉米油日粮是纯化的半合成日粮，在热量的基础上是等营养素的。所有动物单独饲养在单个笼中;在整个研究期间每天计算每只动物的摄食量。致癌物处理后16周，组I、III和IV中每只大鼠的平均乳腺癌数量（±SE）分别为4.1±0.6、6.8±0.7、3.0±0.3和4.1±0.5。组I、II、III和IV中每只大鼠的乳腺癌平均重量（g±SE）分别为3.5 ± 0.7、8.0 ± 1.3、3.0± 1.1和4.6 ± 1.3。与自由采食5%玉米油饲料的动物相比，自由采食20%玉米油饲料的动物乳腺癌数量和重量显著增加（P<0.01）;然而，在饲喂限制性20%玉米油饲料的动物和饲喂限制性5%玉米油饲料的动物之间未观察到乳腺肿瘤数量或重量的显著差异。重复了涉及饲喂12%限制饮食的动物的研究（38只大鼠/组），结果几乎相同，即，在研究结束时，在喂食限制性5%脂肪和20%脂肪饮食的组中，每只大鼠的乳腺癌平均数量分别为3.1 ± 0.4和3.7 ± 0.3，每只大鼠的乳腺癌平均重量（g）分别为4.3 ± 1.2和4.0 ± 1.1（无显著差异）。因此，高水平的膳食脂肪可显著增强雌性大鼠的乳腺癌发生，但仅限于自由采食的动物。稍微限制摄入量（比自由采食量少12%）消除了高脂和低脂饮食之间的乳腺癌差异。
Female 55-day-old Sprague-Dawley rats were treated with a single intravenous dose of 7,12-dimethylbenzanthracene (DMBA), 2 mg/100g of body weight each. At 60 days of age, the rats were divided into four dietary groups (41–42 rats/group): I,5% corn oil diet fed ad libitum; II, 20% corn oil diet fed ad libitum; III,5% corn oil diet fed 12% less than group I; and IV, 20% corn oil diets fed 12% less than group II. The 5% and 20% corn oil diets were purified semisynthetic diets that were isonutrient on a caloric basis. All animals were housed individually in single cages; food consumption of each animal was computed daily throughout the study. Sixteen weeks after carcinogen treatment, mean numbers of mammary carcinomas per rat (±SE) in groups I, III, and IV were 4.1±0.6, 6.8±0.7, 3.0±0.3, and 4.1±0.5, respectively. Mean weight of mammary carcinomas per rat (g±SE) in groups I, II, III, and IV were 3.5 ± 0.7, 8.0 ± 1.3, 3.0± 1.1, and 4.6 ± 1.3, respectively. Mammary carcinoma number and weight were significantly (P<.01) increased in the animals fed the 20% corn oil diet ad libuitum when compared with those fed the 5% corn oil diet ad libitum; however, no significant differences in mammary tumor number or weight were observed between the animals fed a restricted, 20% corn oil diet and those fed a restricted, 5% corn oil diet. The study involving the animals fed the 12%-restricted diets was repeated (38– rats/group), with virtually indentical results, i.e., the mean number of mammary carcinomas per rat in the groups fed the restricted 5% fat and 20% fat diets at termination of the study was 3.1 ± 0.4 and 3.7 ± 0.3, respectively, and the mean weight (g) of mammary carcinomas per rat was 4.3 ± 1.2 and 4.0 ± 1.1, respectively (no significant differences). Thus, high levels of dietary fat can significantly enhance mammary carcinogenesis in female rats, but only in animals on an libitum feeding protocol. A slight restriction in amount consumed (12% less than ad libitum) abolished the mammary carcinogenic differential between a high-fat and a low-fat diet.