Lipid, analysis inhibition

It appears that dc novo synthesis of saturated fatty acids in the endoplasmic reticulum is not strongly inhibited by fatty acids and acyl CoA s whereas the formation of these acids in the mitochondria, probably by elongation, is completely inhibited under these conditions. Thus the appearance of elongation products in the mitochondria in a mixed incubation may very well involve a transfer process. In order to test this probability, microsomes and mitochondria were incubated separately under optimal conditions with radioactive malonyl or acetyl CoA and in the presence or absence of linoleate. They were then washed free of precursors, and the unincubated particles were added, followed by incubation, separation, and fatty acid and lipid analysis. It can be seen in Tables 3 and 4 that there is very rapid exchange of elongation products in both directions despite the absence of the cytosol which presumably contains... 

In vitro, allicin and related compounds inhibit HMG-CoA reductase, which is involved in cholesterol biosynthesis (see Chapter 35 Agents Used in Hyperlipidemia). Several clinical trials have investigated the lipid-lowering potential of garlic. Some have shown significant reductions in cholesterol and others no effect. The most recent meta-analysis suggested a minor (5%) reduction of total cholesterol that was insignificant when dietary controls were in place. 

The antiatherosclerotic effect of proanthocyanidin-rich grape seed extracts was examined in cholesterol-fed rabbits. The proanthocyanidin-rich extracts [0.1% and 1% in diets (w/w)] did not change the serum lipid profile, but reduced the level of the cholesteryl ester hydroperoxides (ChE-OOH) induced by 2,2/-azo-bis(2-amidinopropane-dihydrochloride (AAPH), the aortic malonaldehyde (MDA) content and severe atherosclerosis. The immuno-histochemical analysis revealed a decrease in the number of the oxidized LDL-positive macrophage-derived foam cells on the atherosclerotic lesions of the aorta in the rabbits fed the proanthocyanidin-rich extract. When the proanthocyanidin-rich extract was administered orally to the rats, proantho-cyanidin was detected in the plasma. In an in vitro experiment using human plasma, the addition of the proanthocyanidin-rich extract to the plasma inhibited the oxidation of cholesteryl linoleate in the LDL, but not in the LDL isolated after the plasma and the extract were incubated in advance. From these results, proanthocyanidins of the major polyphenols in red wine might trap ROSs in the plasma and interstitial fluid of the arterial wall, and consequently display antiatherosclerotic activity by inhibiting the oxidation of the LDL [92]. 

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