Ct-linolenic acid

Linolenic acid [ct-linolenic acid, (a/f-Z)-9,12,lS-oc-tadecatrienoic acid]. 

Examples of dietary omega-3 FAs are a-linolenic add (ALA C,83), eicosapen-taenoic acid (EPA Cjo s), and docosahexaenoic acid (DHA C226)- ct-linolenic acid is foimd primarily in soybean oil and flaxseed oil, but we are more likely to obtain EPA and DHA from fish oils. The latter molecules are converted to prostaglandins (PG3) of the 3 series and leukotrienes (LT5) of the 5 series. 

LA, linoleic acid ALA, ct-linolenic acid AA, arachidonic acid DHA, docosahexaenoic acid ERA, eicosapentaenoic acid TRANS-FA, frans-fatty adds SAT, saturated fatty acids MONOs, monounsaturated fatty acids. 

Mammals can insert a cts-alkene into the chain, providing that it is no further away from the carbonyl group than C9. We cannot synthesize linoleic or linolenic acids (see chart a few pages back) directly as they have alkenes at Cl 2 and Cl 5. These acids must be present in our diet. And why are we so keen to have them They are needed for the synthesis of arachidonic acid, a C20 tetraenoic acid that is the precursor for some very interesting and important compounds. Here is the biosynthesis of arachidonic acid. 

Fig. 4. Gas chromatograms and distribution of radioactivity in % of polyunsaturated fatty acids of rat liver, (a) Fat-free diet with addition of linoleic acid, at the end of the experiment 14-Ct<-A t2-Cjg.2. (b) Fat-free diet with addition of linolenic acid, at the end of the experiment (c) Normal diet...

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