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更新时间:2017-8-8 18:52:58 来源:纽约时报中文网 作者:佚名

Researchers Track an Unlikely Culprit in Weight Gain

For middle-aged women struggling with their weight, a recent spate of scientific findings sounds too good to be true. And they may be, researchers caution.


Studies in mice indicate that a single hormone whose levels rise at menopause could be responsible for a characteristic redistribution of weight in middle age to the abdomen, turning many women from “pears” to “apples.” At the same time, the hormone may spur the loss of bone.


In mouse studies, blocking the hormone solves those problems, increasing the calories burned, reducing abdominal fat, slowing bone loss and even encouraging physical activity.


The notion that such a simple intervention could solve two big problems of menopause has received the attention of researchers and has prompted commentaries in prestigious journals like The New England Journal of Medicine and Cell Metabolism.

这种据称可以解决更年期两大问题的简单干预措施,得到了研究人员的关注,并得到《新英格兰医学杂志》(New England Journal of Medicine)和《细胞-代谢》(Cell Metabolism)等著名期刊的报道。

“It’s a super interesting idea,” said Dr. Daniel Bessesen, an obesity expert and professor of medicine at the University of Colorado School of Medicine. With obesity rising, “we definitely need some new ideas.”

“这是一个超级有趣的想法,”科罗拉多大学医学院肥胖问题专家和医学教授丹尼尔·贝塞森(Daniel Bessesen)说。随着肥胖问题的增加,“我们肯定需要一些新的想法。”

The work began when Dr. Mone Zaidi, a professor of medicine at the Icahn School of Medicine at Mount Sinai in New York City, became curious about whether a reproductive hormone — F.S.H., or follicle-stimulating hormone — affects bone density.

这项工作始于纽约市西奈山伊坎医学院(Icahn School of Medicine at Mount Sinai)的医学教授莫尼·扎伊迪(Mone Zaidi),他对FSH生殖激素(或称促卵泡激素)给骨密度带来的影响感到好奇。

It had long been assumed that the hormone’s role was limited to reproduction. F.S.H. stimulates the production of eggs in women and sperm in men.


Researchers knew that blood levels of F.S.H. soar as women’s ovaries start to fail before menopause. At the same time, women rapidly lose bone — even when blood levels of estrogen, which can preserve bone, remain steady.


Dr. Zaidi reasoned that F.S.H. could be a culprit in bone loss. So he and his colleagues created an antibody that blocked F.S.H. in female mice whose ovaries had been removed.


Since the mice were making no estrogen at all, they ought to have been losing bone. Indeed, the bone marrow in such mice usually fills with fat instead of developing bone cells. Much the same happens in women: That’s why their bones become less dense.


But in Dr. Zaidi’s lab, the mice that received the antibody did not developed fat-filled bone marrow — and, to his enormous surprise, they lost large amounts of fat.


“This is a weird, weird finding,” he recalled telling his friend Dr. Clifford J. Rosen, a bone specialist at Maine Medical Center Research Institute. Dr. Zaidi persuaded Dr. Rosen to help repeat the experiments independently, each in his own lab.

“这是一个非常奇怪的发现,”他回忆自己当时把这个发现告诉了朋友、缅因州医学中心研究所(Maine Medical Center Research Institute)的骨科专家克利福德·J·罗森(Clifford J. Rosen)。扎伊迪劝说罗森,在后者的实验室中独立地重复这一实验。

At first, Dr. Rosen was dubious: “I said, ‘I don’t believe it, I think it’s not going to work, and it will cost a lot of money.’” But he received a grant for the research, and the two labs got started.


Two and a half years later, they had their results — and they replicated Dr. Zaidi’s original findings. The researchers also came up with a theory that might explain increased metabolic rates in mice in which F.S.H. is blocked.


There are two kinds of fat in the body: White fat primarily stores energy, and brown fat burns calories and throws off heat.


Brown fat is more common in children, but researchers have found that adults also carry small amounts. In the experimental mice, white fat was being converted to brown fat.


At the moment, Dr. Rosen is withholding judgment about whether the results will apply to humans. “I think the idea has some credibility,” he said. “But does it mean anything? I don’t know.”


But these are not the only researchers to find a link between obesity and the strange interplay of hormones.


Wendy Kohrt, a professor of medicine at the University of Colorado, has been studying the effects of menopause on women’s body fat and the amount of calories women burn.

科罗拉多大学医学教授温迪·柯尔特(Wendy Kohrt)一直在研究更年期对女性体脂以及女性卡路里燃烧的影响。

Dr. Kohrt has given healthy premenopausal women a drug that blocks production of estrogen and F.S.H., putting them into a reversible state of menopause.


Within five months, she found, the women’s fat moves to their abdomens, increasing by 11 percent on average. And they burn 50 fewer calories per day.


The effect is reversed when the participants stop taking the drug or when Dr. Kohrt gives them estrogen.