Intersting finding on control of leptin:
Researchers Link Gene to Hispanic, Black Obesity
By DON FINLEY
c.1998 San Antonio Express-News
SAN ANTONIO -- Researchers say they have pinpointed a gene
that appears to have a major effect on obesity in both Mexican
Americans and African Americans by regulating the hormone leptin.
Variations in the gene appear to be responsible for about half the high
leptin levels found in both ethnic groups, said Anthony Comuzzie, a
geneticist at Southwest Foundation for Biomedical Research.
''This is a remarkable finding,'' he said.
Leptin is produced by another gene, the OB gene, and is secreted by
fat cells. Researchers believe there is a correlation between high leptin
levels in the blood and obesity.
Discovery of a regulatory gene for leptin could lead to a better
understanding of the hormone's complex mechanism and provide clues
toward better treatments for obesity, Comuzzie said.
About a third of Americans are considered obese and the percentage
is even higher among minorities.
Obesity has been linked to diabetes, high blood pressure, heart
disease, osteoarthritis and some cancers.
Comuzzie discussed the still-unpublished findings at the Southwest
Foundation Forum meeting here Wednesday. A similar presentation
was presented at the same time at a scientific meeting in San Diego.
The gene, called POMC, which stands for proopiomelanocortin, is
located on Chromosome 2.
Last year, the group published a report in the journal Nature Medicine
that said they had narrowed the search for the gene to a region on
Chromosome 2.
''This is the strongest indication of a gene being involved in this type of
trait,'' Comuzzie said.
The findings are the latest from the San Antonio Family Heart Study, a
seven-year study of some 1,400 Mexican Americans in San Antonio.
After proving the genetic association in Mexican Americans, the group
collaborated with researchers in Chicago to confirm the findings in a
group of 600 blacks, Comuzzie said.
In November, researchers at Oregon Health Sciences University in
Portland published a study in Science magazine linking high leptin
levels and obesity in mice to a defect in a part of the brain affected by
the protein produced by the POMC gene.
''POMC was studied quite extensively in the late '70s through the
'80s, mainly for neurological implications,'' Comuzzie said. ''It was
implicated early on in schizophrenia and other things, which never
panned out.''
Comuzzie said the POMC gene has a complicated role in the
regulation of several important body systems, particularly in the brain.
Leptin has been the subject of intense research since scientists at
Rockefeller University in New York demonstrated three years ago it
caused fat mice to shed weight. |
