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Old 07-22-2010
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Drug Fibrates Mechanism of action?

in the first aid book, the diagram shows that gemfibrozil stimulates lipoprotein lipase, which would break down VLDL to IDL, but how would that reduce cholesterol?

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Old 07-22-2010
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Lipoprotein lipase is needed to hydrolize lipids from chylomicrons and VLDL. So it takes the lipids from these particles and free them as fatty acids. These fatty acids will then be combined with glycerol 3-P (that comes from glycolysis) to from triglycerides which are stored in adipose tissue.

If you stimulate lipoprotein lipase then you are certainly going to enhance the process mentioned above and so you are going clean up your chylomicrons and VLDL off their triglycerides content.

By the way it does not have much effects on cholesterol that's why fibrates are mainly indicated in hypertriglyceridemia such as Type III and Type IV. Not Type I or Type II.
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Old 07-22-2010
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Quote:
Originally Posted by LionofJudo View Post
in the first aid book, the diagram shows that gemfibrozil stimulates lipoprotein lipase, which would break down VLDL to IDL, but how would that reduce cholesterol?

thanks

without lipoprotein lipase (LPL), the adipose tissue cannot take up chylomicrons. cholesterol esters (not cholesterol) are absorbed from the intestine n packaged in chylomicrons, then the LPL (at adipose tissue) hydrolyzes this complex to form chylomicron remnant, which is taken to the liver, then back out again as VLDL (which now carries cholesterol).

then it is transported back to the adipose tissue, where LPL hydrolizes it to form IDL. this is then transported back to the liver. in the adipose tissue, the LPL is used to hydrolyze the FA from the TGs carried by this chylomicron n VLDL.

remember, LPL is activated by apoC.

it is in kaplan notes (biochem) but it was best explained in the kaplan videos (biochem).
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thank you!
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Old 07-23-2010
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this is somewhat related - How does niacin cause hyperuricemia and hyperglycemia
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Quote:
Originally Posted by Seetal View Post
without lipoprotein lipase (LPL), the adipose tissue cannot take up chylomicrons. cholesterol esters (not cholesterol) are absorbed from the intestine n packaged in chylomicrons, then the LPL (at adipose tissue) hydrolyzes this complex to form chylomicron remnant, which is taken to the liver, then back out again as VLDL (which now carries cholesterol).

then it is transported back to the adipose tissue, where LPL hydrolizes it to form IDL. this is then transported back to the liver. in the adipose tissue, the LPL is used to hydrolyze the FA from the TGs carried by this chylomicron n VLDL.

remember, LPL is activated by apoC.

it is in kaplan notes (biochem) but it was best explained in the kaplan videos (biochem).
what is the difference between esterified cholesterol (on chylomicron) and just cholesterol (on VLDL) ?
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