Here's more on Leptin:
Tuesday March 3 1:25 PM EST
Leptin May Help Trigger Puberty
NEW YORK (Reuters) -- In mice, mutations in the leptin gene lead to severe obesity and infertility.
Now, scientists have discovered that in humans, mutations of this gene may lead to low levels of
leptin -- and individuals with two copies of the mutant gene have very low leptin levels associated
with reproductive abnormalities, including a failure to enter puberty.
The scientists, led by Professor A. Donny Strosberg of Universite de Paris, France, report their
discovery in Nature Genetics. In a previous study, the only two obese patients with confirmed
mutations in the leptin gene were children, so it was not possible to determine the effects of the
genetic mutation on their reproductive function.
Strosberg and his team found a Turkish family in which two obese adults had mutations in both
copies of the leptin gene. One of these individuals, a woman, had primary amenorrhea -- she had
never menstruated. The second was a male who "...had never entered into puberty and had clinical
features of hypogonadism: no beard, scanty pubic and axillary (underarm) hair, bilateral
gynecomastia (enlarged breasts), and small penis and testes," write the researchers. Strosberg's team
reports family members who were not affected by the mutation "...had normal body weight."
The male also had low levels of testosterone, but levels of the hormone rose when he was given a
hormone that stimulated testosterone production. "These results... establish that leptin indeed plays an
important role in human reproductive function," conclude the researchers.
The researchers believe their findings suggest "...that leptin not only controls body mass but may also
be a necessary signal for the initiation of human puberty." SOURCE Nature Genetics
(1998;18:213-215) |
