Word: leptin
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Dates: during 2000-2009
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Some of the most provocative sleep research doesn't have anything to do with the brain at all. A few years after researchers isolated a natural hormone they called leptin, which tells the brain that the body has enough fatty tissue, Eve Van Cauter and her colleagues at the University of Chicago began to wonder whether sleep deprivation has any effect on the amount of leptin in the blood. They soon discovered that after just a couple of days in which 12 male volunteers were allowed to get only four hours of sleep a night, their leptin levels fell sharply...
There are many other factors that affect this delicate balance. For example, laboratory evidence suggests that a diet that boosts your triglycerides--typically, one high in fatty, fried or highly refined foods--may interfere with both leptin's and insulin's actions on the brain, leading to an erroneous signal that the body is in danger of starving. The same receptors in the brain that are responsible for a marijuana high also boost appetite, which is why pot smokers get the munchies...
Doctors used to joke that the best way to combat obesity was to build up your biceps ... in order to push yourself away from the table. Then came the discovery in 1995 of genes that regulate leptin, the hormone that controls how much fat your body stores. Since then, scientists have identified dozens of compounds related to weight, some released in the brain and others...
Scientists at Regeneron, based in New York, are tapping into the same feeding hub in the brain but through a different protein that is more closely related to leptin. Regeneron's agent, Axokine, fools the brain into thinking that the body's fat stores are well stocked, short-circuiting the need to eat. People who took Axokine and stayed on a low-calorie diet and exercise program lost twice as much weight as those who relied on diet and exercise alone...
Even more exciting is a compound that appears to attack obesity through both the brain and the gut. Called rimonabant, and developed by Paris-based Sanofi, it is entering the final stages of human testing. Like Axokine and leptin, rimonabant was designed to make the body feel full. But scientists were pleasantly surprised to find that it also lowered triglyceride levels 15% and raised good cholesterol 22%--far more than would have been expected from weight loss alone. There is also evidence that patients on rimonabant may become more sensitive to the action of insulin, which can halt the progression...