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How insulin resistance causes high cholesterol
It all begins when key cells start to ignore insulin.
The glucose gates don’t swing open on cue. Glucose molecules get stuck on the outside and……… more and more of them arrive. And in a flash, sugar levels rise to DANGEROUS.
Prompting a metabolic crisis.
With enough yelling and screaming and insulin reinforcements, the glucose eventually gets moved out of the circulation.
And uneasy “peace” returns, until the next meal.
And then it all begins again.
The other half of the story
Well that is how the story goes, but truth be told, this is only half the story. It is the story that gets everyone’s attention because
HIGH SUGAR LEVELS are TOXIC !
But, insulin is not just in charge of sugar. Officially, he is in charge of putting ALL the groceries away.
All the groceries includes sugar, amino acids and fats.
Partnering with the liver
Now he does have to co-ordinate his activities with the liver. You see, the liver is in charge of feeding everyone, when insulin is NOT around.
It is a very important job.
The liver has to keep the brain supplied with SUGAR !
If sugar supplies in the blood are low, the liver has to whip up a batch of sugar pronto, in a process known as gluconeogenesis. It is quite literally a matter of life and death, since parts of the brain can’t use anything else.
And a STARVING brain is life ending.
Two cooks spoil the broth
When insulin is supervising the putting away of the groceries, he doesn’t want competition.
Insulin wants to be the EXCLUSIVE provider.
So he tells the liver to stop sugar production i.e. gluconeogenesis decreases.
Not forever of course, but just long enough, to get the groceries packed away safely. Worried that the liver will be bored, he encourages the liver to switch it’s attention to fat production i.e. lipogenesis increases.
This is pretty important, since when there are a lot of groceries, it is prudent to store them up………………. for rainy days.
SREBP1c (Sterol Regulatory Element binding protein 1 c) is the little guy who carries out insulin’s orders, in the fat production department. He kick starts the fat production system, which involves arranging for several fat metabolising enzymes to come on line and get busy.
Now we’re told, the problem in insulin resistance, is the cells IGNORE INSULIN.
So we’re “expecting”
Glucose production to continue. And fat production to cease.
But this is not what happens.
Glucose production does continue, but fat production goes into overdrive.
SREBP1c on his own agenda. And this is what contributes to a lot of the metabolic mayhem.
Insulin resistance is selective
Instead of lipogenesis being something that happens in response to the arrival of a big supply of groceries. Fat production is an on going process. As a consequence fat burning, happens on high days and holidays – it’s rather hard to store and burn fat, simultaneously.
One of the consequences of this continuous fat production in the liver is a FATTY LIVER.
What to do with all that fat ?
Too much fat
Grappling with a self-induced oversupply of fats, the liver makes a plan to distribute it. So fat levels (triglycerides) in the blood rise, along with cholesterol (the cholesterol is involved in fat transport).
Fat cells try hard to take up all the extra fat, until they too fail.
Cells are spoilt for choice
If you’re delivering food across the body, you don’t want the liver, stealing your thunder, by waving juicy fatty acids to all the cells, you’re servicing.
Insulin’s grocery delivery programme is thwarted.
Cells become fussy !
The cells turn a deaf ear to insulin’s cries, to open up and take up some sugar…… they’re just not hungry !
Leading to “insulin resistance”…….
Why the “dis-obedience” ?
Researchers from South University of Texas Southwestern Medical Center think they know why.
SREBP1c is not actually ignoring insulin per se, he has ANOTHER BOSS.
THE BIG BOSS !
Is this the REAL bogey man in metabolic syndrome ? Is insulin just the fall guy ? Maybe…………
The chemistry of fats is complicated. High fat levels are not because you stacked your plate with butter, meat, cream and eggs – your body made those fats.
In the middle of the night, muscles aren’t busy and the brain is taking it easy, so when your live makes sugar, it has nowhere to go, giving you fasting hyperglycemia
When the right workers are on the job, things run pretty smoothly but keeping fat production running smoothly in the liver requires tight supervision.