Here's the Reuter's story:
WASHINGTON (Reuter) - A hormone linked to appetite and obesity may be
the trigger that sets off the complex cascade of events in puberty,
scientists said Thursday.
The study by molecular geneticist Farid Chehab and colleagues at the
University of California-San Francisco, appears Friday in the journal
Science.
Although the research on the hormone leptin, done on female mice, has no
immediate clinical applications for humans, it eventually may lead to new
ways of treating certain reproductive disorders, such as the problems women
with anorexia nervosa often experience, Chehab said in a telephone interview.
``It's very important to find out what is the switch that starts the
cascade of events that lead to reproductive function,'' he said. ``Leptin is
an important signal.''
Researchers have long suspected a link between body fat and the onset of
puberty. According to this theory, a girl must reach a ``critical fat'' level
to start puberty.
Obese girls reach puberty earlier in life than girls of normal weight.
And very thin girls, like ballet dancers, may experience delayed puberty.
``We know that a deficiency in fat causes reproductive problems,'' Chehab
said, adding his research suggests these girls have low levels of leptin.
Leptin, identified about two years ago, is contained in fat tissue.
Scientists are studying how it sends signals to the brain that affect
appetite and weight control.
In this experiment Chehab treated normal pre-pubescent mice with leptin
injections. They lost weight, and ate less, as expected.
But the presence of the extra leptin tricked the brain into thinking the
mice had reached the critical fat level, and the mice matured reproductively
sooner than the control group.
Last year, Chehab and colleagues found that leptin treatments enabled
sterile, obese mice to become pregnant and deliver healthy babies.
17:28 01-02-97 |
