A comparison was made of neutral lipid biosynthesis by intact Euchaeta norvegica, gut tissue isolated from E. norvegica and the E. norvegica from which the gut tissue had been removed. Incorporation of radioactive glucose and alanine into triacylglycerols by all three systems exceeded that into wax esters. Whereas 86.7% of the glucose incorporated into triacylglycerols by gut tissue was located in the glycerol moiety, only 21.8 and 23.8% of glucose incorporated into triacylglycerols by intact and disembowelled copepods, respectively, was recovered in the glycerol moiety. Incorporated alanine in triacylglycerols was always located preferentially in the fatty acid moiety. Radioactive hexadecanol was always extensively incorporated into wax esters, with internal tissues being much more active than gut tissue. The major portion of glucose and alanine incorporated into wax esters was in the fatty alcohol moiety. Gut tissue was much more active than internal tissues in oxidising hexadecanol to hexadecanoic acid. We conclude that gut tissue synthesises glycerol 3-phosphate for use in the esterification of dietary fatty acids to form triacylglycerols. Gut tissue is also activenin oxidising dietary fatty alcohols. Fatty acid biosynthesis, leading to wax ester formation, is a property of internal tissues rather than of the gut.
KeywordsHexadecanoic Acid Neutral Lipid Fatty Alcohol Fatty Acid Biosynthesis Dietary Fatty Acid
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