Cohen L A, Thompson D O
Lipids. 1987 Jun;22(6):455-61. doi: 10.1007/BF02537278.
The N-nitrosomethylurea rat mammary tumor model was used to compare the tumor-promoting effects of a high-fat (HF) diet containing a 3:1 mixture of medium chain triglycerides (MCT) and corn oil with that of a HF and a low-fat (LF) corn oil diet. The serum and tumor lipid content and fatty acid (FA) composition were also determined in the three dietary groups. It was found that the MCT-containing diet failed to promote tumor development compared with the HF corn oil group. Tumor incidence in the HF-MCT group was similar to that of the LF corn oil group (5% fat, w/w), but significantly decreased compared to the HF corn oil group. Total serum cholesterol levels were significantly depressed in the HF corn oil group compared to the HF-MCT and LF corn oil groups. Analysis of serum and tumor FA profiles indicated that the HF corn oil group exhibited approximately twice the amount of linoleic acid (LA) as the other two treatment groups. Differences among the three groups in the major FA metabolite of LA, arachidonic acid, were minimal. These results are consistent with the hypothesis that tumor promotion by dietary fat is more a function of the type than the amount of fat ingested. In addition, they indicate that MCT, due at least in part to their unique structural and physiological properties, exert markedly different effects on mammary tumor development than conventional long chain unsaturated fatty acids.
采用N-亚硝基甲基脲大鼠乳腺肿瘤模型，比较含中链甘油三酯（MCT）与玉米油比例为3:1的高脂（HF）饮食、高脂玉米油饮食和低脂（LF）玉米油饮食的促肿瘤作用。还测定了三个饮食组的血清和肿瘤脂质含量以及脂肪酸（FA）组成。结果发现，与高脂玉米油组相比，含MCT的饮食未能促进肿瘤发展。高脂MCT组的肿瘤发生率与低脂玉米油组（5%脂肪，w/w）相似，但与高脂玉米油组相比显著降低。与高脂MCT组和低脂玉米油组相比，高脂玉米油组的总血清胆固醇水平显著降低。血清和肿瘤FA谱分析表明，高脂玉米油组的亚油酸（LA）含量约为其他两个治疗组的两倍。LA的主要FA代谢产物花生四烯酸在三组之间的差异最小。这些结果与以下假设一致，即饮食脂肪的促肿瘤作用更多地取决于脂肪的类型而非摄入的量。此外，它们表明，MCT至少部分由于其独特的结构和生理特性，对乳腺肿瘤发展的影响与传统的长链不饱和脂肪酸明显不同。
