Key regulator of blood glucose levels discovered
- From: "GysdeJongh" <jongh711@xxxxxxxxx>
- Date: Mon, 12 Sep 2005 00:37:44 +0200
http://www.salk.edu/news/releases/details.php?id=144
Key regulator of blood glucose levels discovered
September 09, 2005
La Jolla, CA - In many patients with type 2 diabetes, the liver acts like a
sugar factory on overtime, churning out glucose throughout the day, even when
blood sugar levels are high. Scientists at the Salk Institute for Biological
Studies discovered a key cellular switch that controls glucose production in
liver cells.
This switch may be a potential new target for the development of highly specific
diabetes drugs that signal the liver to reduce the production of sugar. The Salk
researchers, led by Marc Montminy, a professor in the Clayton Foundation
Laboratories for Peptide Biology, published their findings in the Sept. 7th
online issue of Nature.
"It is very exciting to understand how glucose production in the liver is
regulated. Now, we can try to improve the way how type 2 diabetics handle blood
sugar," says Montminy.
The newly discovered switch, a protein named TORC2, turns on the expression of
genes necessary for glucose production in liver cells.
When describing glucose's role in health and disease, Montminy compares the
human body to a hybrid car that runs on a mix of fuels depending on its activity
status: gas, or glucose, is used for high-energy activities, and battery power,
or body fat, for low-energy activities. During the day, when food refuels the
"gas tank," the body burns mainly glucose, and during sleep, it burns primarily
fat.
The body switches from glucose to fat burning mainly in response to two key
hormones -- insulin and glucagon -- that are produced by the pancreas. During
feeding, the pancreas releases insulin, which promotes the burning of glucose.
At night, however, the pancreas releases glucagon into the bloodstream, which
signals the body to fire up the fat burner.
But even during sleep, our brain needs a constant supply of glucose to function
properly. For that reason, our body actually manufactures glucose during sleep o
r when we are fasting. That process, called gluconeogenesis, is carried out
mainly in the liver.
Insulin normally shuts down the ability of the liver to produce glucose. In
individuals with Type II diabetes, however, insulin is unable to inhibit sugar
production in the liver, "either because the pancreas is not producing enough
insulin or because insulin's signal can't be 'heard,'" says Montminy. When the
liver is unable to hear the insulin signal, excess glucose builds up in the
bloodstream.
In addition to so-called insulin sensitizing drugs that allow insulin to work
better, researchers are looking for alternative ways to shut down the production
of glucose in the liver of diabetics. "Figuring out how to control glucose
production in the liver is critical because many complications of diabetes, such
as heart disease, kidney failure and blindness, can be reduced by maintaining a
very tight control over blood sugar levels," he says.
As glucose levels run low during fasting, the pancreas sends out the hormone
glucagon and instructs the liver to produce glucose. This increase in glucagon
turns on the TORC2 switch and allows the liver to make more glucose. Mice that
were genetically modified to make more or less TORC2 produced more or less
glucose depending on the amount of available TORC2 (transducer of regulated CREB
activity).
Most of the time, TORC2 sits in the cellular compartment that surrounds the
nucleus, where all the genes are located. When a glucagon signal arrives, the
TORC2 switch crosses the nuclear membrane, teams up with the transcriptional
activator CREB and turns on all the genes necessary for gluconeogenesis. "Being
located in a different part of the cell is what keeps the TORC2 switch off,"
explains Montminy.
The researchers also discovered that a chemical modification on TORC2 itself
sequesters the protein in the cytoplasm, the viscous substance inside the cell
that surrounds the nucleus. "Since we now know the molecular mechanism by which
TORC2 is inactivated we can start looking for small molecules that do the same
thing," says Montminy.
The Salk Institute for Biological Studies in La Jolla, California, is an
independent nonprofit organization dedicated to fundamental discoveries in the
life sciences, the improvement of human health and the training of future
generations of researchers. Jonas Salk, M.D., whose polio vaccine all but
eradicated the crippling disease poliomyelitis in 1955, opened the Institute in
1965 with a gift of land from the City of San Diego and the financial support of
the March of Dimes.
I do not know what it means....
Today I babysitted my grand daughter for the first time
Afterwards my daugther told me that I was the first who she trusted to do
that...
She gave me a bottle of wiskey....
I said that that was totally not neccessary
And that she should not do that the next time
Well....
The whole bottle of wiskey is finished now , as we would expect :(
So...
Bit drunk
And uncoherent
I don't know if it has something to do with this :
Protein plus excercise key combination contribution by :
Quentin Grady
Read mTOR at :
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=2475
Read TORC2 at :
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=200186
Gys
.
- Prev by Date: Re: OT Most Detested Exercise
- Next by Date: Re: PING, CHUCK
- Previous by thread: OT A LETTER TO ALL WHO VOTED FOR GEORGE BUSH
- Next by thread: High-Carb, Vegan Diet Causes Major Weight Loss
- Index(es):
Relevant Pages
|
Loading
