研究表明 基因或是導致中年發福的原因大綱

U.S. researchers said Tuesday that they have identified an enzyme that may play a central role in the development of obesity in mid-life.

美國研究人員上週二表示，他們發現了一種可能在中年人發福現象中起到核心作用的酶。

In two groups of mice being fed high-fat foods, those who received an inhibitor that blocked the enzyme had a 40 percent decrease in weight gain compared with those that did not receive the drug.

在兩組餵食高脂肪食物的小白鼠中，一組被使用了阻斷這種酶的抑制劑，結果發現，相比於另一組沒有用藥的小白鼠，這組小白鼠的體重增加量要低40%。

The findings, published in the U.S. journal Cell Metabolism, could upend current notions about why people gain weight as they age, and could one day lead to more effective weight-loss medications.

刊載於美國雜誌《細胞新陳代謝》上的該發現，可能會顛覆人們對於隨着年齡增長身體發福這一現象的認知，或許有一天能夠有助於研製出更有效的減肥藥。

"Our society attributes the weight gain and lack of exercise at mid-life (approximately 30 to 60 years) primarily to poor lifestyle choices and lack of will power, but this study shows that there is a genetic program driven by an overactive enzyme that promotes weight gain and loss of exercise capacity at mid-life," said lead study author Jay H. Chung, head of the Laboratory of Obesity and Aging Research at the National Heart, Lung, and Blood Institute (NHLBI), part of the U.S. National Institutes of Health.

Jay H. Chung是這項研究的主要作者，他是美國心肺血液研究所（該研究所是美國國家衛生研究院的一部分）下屬肥胖和衰老研究室主任，他說道：“我們的社會通常認爲，中年人（30到60歲）體重增加和缺乏鍛鍊，是因爲不良的生活方式和缺乏意志力的原因，但是這項研究表明也存在着遺傳因素--一種過度活躍的酶會使得人們中年時體重增加、喪失運動能力。”

Chung and his associates searched for biochemical changes that occurred in middle-aged animals that are equivalent to 45 years in humans. They found that an enzyme called DNA-dependent protein kinase, or DNA-PK, increases in activity with age.

Chung和他的同事們在中年動物（相當於45歲的人類）的身體上尋找生物學變化。他們發現，隨着年齡的增長，一種被稱之爲DNA依賴性蛋白激酶的物質的活性與日俱增。

Further work showed that DNA-PK promotes conversion of nutrients to fat and decreases the number of mitochondria, tiny organelles in the cells that turn fat into energy to fuel the body.

進一步的研究發現，DNA依賴性蛋白激酶會促進營養物質轉化爲脂肪，並且減少線粒體的數量--而線粒體是將脂肪轉化爲能量以供應人體的細胞器。

Mitochondria can be found in abundance among young people, but the numbers drop considerably in older people. Researchers know that decreased mitochondria can promote obesity as well as loss of exercise capacity.

年輕人體內存在着大量線粒體，但是老年人體內線粒體的數量卻大幅下降。研究人員發現，線粒體數量的減少會促進肥胖、並且導致運動能力喪失。