Xue C Y, Kageyama H, Kashiba M, Kobayashi A, Osaka T, Namba Y, Kimura S, Inoue S
Division of Geriatric Health and Nutrition, National Institute of Health and Nutrition, Toyama, Shinjuku-ku, Tokyo, Japan.
Int J Obes Relat Metab Disord. 2001 Mar;25(3):434-8. doi: 10.1038/sj.ijo.0801548.
To clarify the mechanism by which plasma triacylglycerol is affected by a high fat or a sucrose diet.
Two sets of six groups each having six rats were prepared-(1) ventromedial hypothalamic (VMH)-lesioned rats fed a standard diet; (2) sham VMH-lesioned rats fed a standard diet; (3) VMH-lesioned rats fed a high-fat diet; (4) sham VMH-lesioned rats fed a high-fat diet; (5) VMH-lesioned rats fed a high-sucrose diet; and (6) sham VMH-lesioned rats fed a high-sucrose diet. After VMH lesions and sham operations, the rats were provided standard, high-fat and high sucrose diets for 2 weeks. Two weeks later, blood samples were collected after overnight fast to determine plasma triacylglycerol (TAG), hepatic triacylglycerol secretion rate (TGSR), fractional catabolic rate (FCR) of triacylglycerol and postheparin plasma lipoprotein lipase (LPL), plasma glucose, insulin and leptin.
Values of TAG, TGSR, FCR and LPL in VMH-lesioned obese rats were all greater than those in sham-operated rats, regardless of the diet fed. In sham-operated rats, high-fat diet fed rats showed higher TAG with similar TGSR, higher LPL and lower FCR than those of standard diet fed rats. High-sucrose diet fed rats showed significantly higher TAG with higher TGSR, higher LPL and lower FCR than those of standard diet fed rats. Moreover, high-sucrose diet fed rats showed higher TAG with higher TGSR, lower LPL and higher FCR than those of high-fat diet fed rats. In VMH-lesioned rats, high-fat diet fed rats showed higher TAG with similar TGSR, higher LPL and lower FCR than those of standard diet fed rats. High-sucrose diet fed rats showed markedly higher TAG with notably higher TGSR, higher LPL and lower FCR than those of standard diet fed rats. High-sucrose diet fed rats showed still higher TAG with markedly higher TGSR, similar LPL and higher FCR than those of high-fat diet fed rats.
The mechanism by which TAG metabolism is affected by a high-fat or a high-sucrose diet differed; a high-fat diet increased plasma TAG level by lowering removal of TAG without increase in hepatic TAG secretion in sham-operated (normal) rats. A high-sucrose diet, in contrast, induced much higher plasma TAG levels by both increased hepatic TAG secretion and decreased removal of TAG. The effects of a high-fat or a high-sucrose diet were similar but exaggerated in VMH lesioned animals.
阐明高脂或高糖饮食影响血浆甘油三酯的机制。
准备两组，每组六组，每组六只大鼠——（1）腹内侧下丘脑（VMH）损伤的大鼠喂食标准饮食；（2）假VMH损伤的大鼠喂食标准饮食；（3）VMH损伤的大鼠喂食高脂饮食；（4）假VMH损伤的大鼠喂食高脂饮食；（5）VMH损伤的大鼠喂食高糖饮食；（6）假VMH损伤的大鼠喂食高糖饮食。VMH损伤和假手术后，给大鼠提供标准、高脂和高糖饮食2周。两周后，过夜禁食后采集血样，测定血浆甘油三酯（TAG）、肝脏甘油三酯分泌率（TGSR）、甘油三酯的分解代谢率（FCR）和肝素后血浆脂蛋白脂肪酶（LPL）、血浆葡萄糖、胰岛素和瘦素。
无论喂食何种饮食，VMH损伤的肥胖大鼠的TAG、TGSR、FCR和LPL值均高于假手术大鼠。在假手术大鼠中，喂食高脂饮食的大鼠与喂食标准饮食的大鼠相比，TAG更高，TGSR相似，LPL更高，FCR更低。喂食高糖饮食的大鼠与喂食标准饮食的大鼠相比，TAG显著更高，TGSR更高，LPL更高，FCR更低。此外，喂食高糖饮食的大鼠与喂食高脂饮食的大鼠相比，TAG更高，TGSR更高，LPL更低，FCR更高。在VMH损伤的大鼠中，喂食高脂饮食的大鼠与喂食标准饮食的大鼠相比，TAG更高，TGSR相似，LPL更高，FCR更低。喂食高糖饮食的大鼠与喂食标准饮食的大鼠相比，TAG明显更高，TGSR明显更高，LPL更高，FCR更低。喂食高糖饮食的大鼠与喂食高脂饮食的大鼠相比，TAG仍然更高，TGSR明显更高，LPL相似，FCR更高。
高脂或高糖饮食影响TAG代谢的机制不同；在假手术（正常）大鼠中，高脂饮食通过降低TAG的清除而不增加肝脏TAG分泌来提高血浆TAG水平。相比之下，高糖饮食通过增加肝脏TAG分泌和降低TAG清除来诱导更高的血浆TAG水平。高脂或高糖饮食的影响相似，但在VMH损伤的动物中更为明显。
