Word: leptin
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...also controls the flow of a hormone called leptin, which affects appetite, energy metabolism and reproduction...
Frisch says a successful pregnancy takes about 50,000 calories more than normal metabolic requirements. If the body does not have the necessary calories, the brain restricts the flow of leptin and switches off the ability to reproduce...
...while it's tempting to think that ghrelin is a magic bullet that could be used to keep us all at a perfect weight, doctors think that's highly unlikely. Similar hopes were raised a few years ago for leptin, a hormone that acts as an appetite suppressant. After years of trying, nobody has found a way to make it into a useful medication, largely because patients quickly develop a leptin tolerance...
What doctors suspect is that both leptin and ghrelin are part of a complex system of brain and body chemicals that have evolved over millions of years to govern weight and appetite. Says Dr. Rudy Leibel, an obesity expert and head of the molecular-genetics department at Columbia University: "It's just unlikely that any single component of this system will necessarily lead to a definitive therapeutic agent...
...announcement of leptin's discovery was big news to biologists, particularly after Friedman administered it to the obese mice and saw their weight drop by a dramatic 30% within as little as two weeks. A next, obvious step was to look for humans with the same defective gene. In Britain, endocrinologist Stephen O'Rahilly of the University of Cambridge did find a pair of leptin-deficient children, one of whom at age 9 weighed a staggering 208 lbs. After modest leptin treatments were begun, both children began dropping weight at a steady rate that sometimes exceeded 4 lbs. a month...