Researchers looking for uses for new fat-fighting
enzyme
November 30, 2004
By Ed Edelson
A newly discovered enzyme that plays a major role in fat metabolism
could be a target for a different kind of weight-loss drug, Austrian
researchers report.
The enzyme, designated ATGL, starts the process by which the body
metabolizes fats, using them for energy. Blocking ATGL's activity
could mean that more fat would exit the body rather than being stored
in what scientists call adipose tissue, says a report in a recent
issue of Science. The research was carried out at the University
of Graz Research Institute of Molecular Pathology.
The enzyme has been identified in mice, said study author Rudolf
Zechner, a scientist at the institute. "Whether such an inhibition
could be beneficial for patients with obesity and type 2 diabetes
remains to be determined," Zechner said. "Right now we
are at the stage of optimistic speculations."
ATGL is a member of a family of enzymes called lipases that act
to metabolize fats. Until now, only one other lipase has been known
to play a role in human fat metabolism. That enzyme, hormone-sensitive
lipase (HSL), was discovered a number of years ago. The drug Xenical,
which blocks the activity of HSL, is marketed by the Roche Pharmaceuticals
for weight reduction.
Asked to assess the Austrian report, Terence J. Hurley, a Roche
spokesman, said, "It really wouldn't be appropriate for us
to comment on this."
Blocking the activity of ATGL might be a more effective strategy
because mouse experiments indicate that HSL blockage results in
unwanted accumulation of fats called diglycerides, Zechner said.
"Inhibition of ATGL, which is much more a triglyceride than
diglyceride lipase, might not show this unwanted side effect,"
he said. "To make a more competent judgment, however, it is
absolutely necessary to analyze ATGL knockout mice."
A knockout mouse is one that has been genetically engineered to
lack a specific enzyme.
Researchers are working to get a better understanding of exactly
what ATGL does, Zechner said, with a marketable product definitely
in mind.
"As soon as these results support our present view that inhibition
of ATGL could be beneficial for lipid (fat) and energy metabolism,
we expect drug companies to develop specific ATGL inhibitors,"
he said.
Source:www.news-press.com
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