|
 |
Biochemistry
Figuring Out Fat - Behind the bulge, there's a lot of activity.
When scientists start
talking about what
molecules do inside
cells, listeners' eyes often start to
glaze over. But when David
Bernlohr, head of the Department
of Biochemistry, Molecular
Biology, and Biophysics, mentions
his sub-cellular research, people
prick up their ears instead.
Bernlohr studies adipocytes, the
cells that suck fat from our bloodstream
and stash it away in our
hips, stomachs, and thighs. In
today's overweight world, plenty
of folks would like to know how
these cells do what they do and
how we can keep them from
doing it so darn well.
Adipocytes were literally lifesavers
for past generations,
helping keep our ancestors from
starving by providing a backup
energy source when food was
scarce. But in a food-saturated
environment, their
fat-hoarding tends
to cause trouble
instead. Thanks to
their diligence, two-thirds
of Americans
are overweight.
Moreover, obesity
directly leads to
other diseases such
as type II diabetes,
hypertension, and
cardiovascular
disease, making it
the nation's number
one health issue.
"Humans evolved
under conditions of
nutrient limitation,"
says Bernlohr.
"Now, with industrialization, we
live in an environment of nutrient
excess, and our bodies don't know
how to respond."
Up until 10 years ago or so,
the prevailing view was that
adipocytes were little more than
expandable containers where our
bodies stocked up supplies for
hard times. "Over the last decade,
that view has changed dramatically,"
Bernlohr says. In addition
to collecting calories, he says, we
now know that adipocytes
"secrete a raft of hormones that
regulates a number of processes"
related to the fate of fat within our
bodies. The more we learn about
how they do this, Bernlohr says,
the better able we will be to direct
their activity so they help rather
than harm us.
David Bernlohr and Ann Hertzel are part of a research group
gaining a new understanding of fat and how it behaves in
the body.
Bernlohr is currently working to
understand how fats enter
adipocytes, how they move once
inside, and how they regulate
genes that might influence the
onset of obesity-related health
problems. In one set of studies
he's looking at the class of
molecules, known as FATPs,
that ferry fat across the cell
membranes. He has cloned the
gene that makes one such ferry.
He has also discovered that a
helper molecule known as
Coenzyme A plays a key role in
their ability to do so.
Within cells, Bernlohr is focusing
on fatty acid binding proteins
(FABPs), which shuttle fatty acids
from one place to another. By
studying animals that lack FABP
genes, he's learning a lot about
the role these proteins play in not
only making fat cells fatter, but
also in sending messages to
other parts of the body that may
result in obesity-related disease.
Bernlohr has not only been
studying adipocytes, he also has
applied what he"s learned to
develop an innovative eating
regimen he calls the Northwoods
Diet. "Miami has its South Beach,
I figure we could have our
Northwoods," he says. The plan
allows carbohydrates in the
morning (to get insulin flowing),
but switches to proteins and fats
in the afternoon, with no food at
all after 7:30 p.m. Bernlohr has
dropped 45 pounds following his
own advice, and says others in his
lab who have tried the plan have
lost weight as well.
-Mary K. Hoff
|
