Cohen L A, Thompson D O, Maeura Y, Weisburger J H
Cancer Res. 1984 Nov;44(11):5023-8.
The mammary tumor-promoting effects of a high-fat (HF) diet (23%, w/w) containing a 3:1 mixture of medium-chain triglycerides (MCT) and corn oil were compared with those of a low-fat (LF) corn oil diet (5%) and a HF: corn oil diet (23%, w/w). It was found that the ingestion of MCT in a HF diet resulted in no detectable tumor-promoting effects in animals initiated with the potent mammary carcinogen N-nitrosomethylurea. Total palpable mammary tumor incidence was 60% in the HF:corn oil plus MCT group, 66% in the LF:corn oil group, and 87% in the HF:corn oil group (p less than 0.03 and p less than 0.06, respectively). However, when palpable adenocarcinomas only were counted, differences in incidence between groups were not statistically significant, HF:MCT (57%) versus HF:corn oil (77%), p less than 0.08. Mean time to first tumor (days) was 122 +/- 40 (S.D.) in the MCT, 117 +/- 36 in the LF:corn oil groups, and 86 +/- 23 in the HF:corn oil group. The cumulative tumor incidence curves were similar for the MCT and LF:corn oil groups (p less than 0.9); however, both curves were significantly different from that of the HF:corn oil group (p less than 0.0099). No differences were found in tumor multiplicity, tumor size, or body weight gain in any of the treatment groups. Assay of serum total cholesterol and triglycerides showed that consumption of 23% corn oil diet significantly depressed serum cholesterol (but not triglyceride) levels compared to the LF:5% corn oil- and the HF:MCT-containing diets. Analysis of serum fatty acid profiles indicated that animals fed 23% corn oil exhibited twice the amount of linoleic acid (C18:2) as did those fed either 5% corn oil or MCT. Differences in other fatty acids were of a much lesser magnitude. These results indicate that the mammary tumor-promoting effect of a HF diet can be diminished by substituting saturated MCT for the more common longer-unsaturated-chain triglycerides. In addition, they suggest an association between promotion of mammary cancer and elevated levels of linoleic acid in serum lipids.
将含中链甘油三酯（MCT）与玉米油比例为3:1的高脂（HF）饮食（23%，w/w）的促乳腺肿瘤作用，与低脂（LF）玉米油饮食（5%）和HF：玉米油饮食（23%，w/w）的作用进行了比较。结果发现，在以强效乳腺致癌物N-亚硝基甲基脲启动的动物中，HF饮食中摄入MCT未产生可检测到的促肿瘤作用。HF：玉米油加MCT组可触及的乳腺肿瘤总发生率为60%，LF：玉米油组为66%，HF：玉米油组为87%（p分别小于0.03和p小于0.06）。然而，仅计算可触及的腺癌时，各组之间的发生率差异无统计学意义，HF：MCT（57%）对HF：玉米油（77%），p小于0.08。MCT组首次出现肿瘤的平均时间（天）为122±40（标准差），LF：玉米油组为117±36，HF：玉米油组为86±23。MCT组和LF：玉米油组的累积肿瘤发生率曲线相似（p小于0.9）；然而，两条曲线均与HF：玉米油组有显著差异（p小于0.0099）。在任何治疗组中，肿瘤多样性、肿瘤大小或体重增加均未发现差异。血清总胆固醇和甘油三酯检测显示，与LF：5%玉米油饮食和含HF：MCT的饮食相比，食用23%玉米油饮食显著降低了血清胆固醇（但不降低甘油三酯）水平。血清脂肪酸谱分析表明，喂食23%玉米油的动物体内亚油酸（C18:2）含量是喂食5%玉米油或MCT的动物的两倍。其他脂肪酸的差异幅度要小得多。这些结果表明，用饱和的MCT替代更常见的长不饱和链甘油三酯可减弱HF饮食的促乳腺肿瘤作用。此外，它们提示血清脂质中亚油酸水平升高与乳腺癌的促进之间存在关联。
