Word: weightness
(lookup in dictionary)
(lookup stats)
Dates: during 1990-1999
Sort By: most recent first
(reverse)
...studying a strain of obese laboratory mice. In a series of ingenious experiments, Coleman surgically joined the blood vessels of an obese mouse to those of a normal-size mouse, creating a sort of artificial Siamese twin. What happened then was astonishing: the fat animal immediately began to lose weight. This suggested that the blood of nonobese mice carried a potent biochemical messenger, one that played a vital role in regulating appetite and metabolism. But the mysterious agent was present in such minuscule quantities that no one was able to isolate...
...reasoned, must be produced by a gene that was defective in the obese mice. So he began to hunt for such a gene, the ob, or obese, gene. Sure enough, late last year, after eight years of effort, Friedman and his colleagues pinpointed the ob gene in both average-weight and obese mice. They then inserted the normal gene into bacterial cells, providing at long last detectable quantities of the protein they called leptin...
...thermostat--or in this case a "fatstat"--to tell the body whether to turn metabolism and appetite up or down. Thus when leptin is low, hunger pangs increase, body temperature drops, and metabolism slows. When leptin is high, everything reverses. In such fashion, the brain strives to keep body weight stable and fluctuations small...
Because leptin is produced in fat tissue, the fatter an animal is, the more leptin its cells should make. Normal mice then respond to weight gain by turning out more leptin. As a result, their appetites slacken and their energy consumption speeds up. But the obese mice cannot produce leptin, so their brains never receive this vital message. "These animals," marvels Friedman, "get fat because they think they're starving, and then when we give them the protein, they get thin because they think they...
...others become fat not because they lack willpower or moral character but because they have a biochemical abnormality. "I'm not lazy or unintelligent," she says. "I do as many of the right things as slimmer people. But something's going on in my body that makes controlling my weight more difficult than it is for everyone else...