Fatty Acid Components of Ovine Tissue Lipids, and The Response to Prolonged Protein Depletion

Abstract

SummaryThe lipids of ovina liver and plasma have been separated by silicic acid chromatography into cholesterol ester, triglyceride, free fatty acid, and phospholipid fractions. Fatty acid constituents of these fractions have been determined by gas chromatography. The lipid content of these tissues was also determined for animals subjected to a prolonged protein depletion. Several significant differences were caused by the experimental diet, with the liver showing more alterations than plasma. The unsaturated C 18 fatty acids were affected to the greatest degree.Implications of these results have been discussed in relation to comparative biochemistry and intermediary lipid metabolism.

Fatty Acid Components of Ovine Erythrocyte Lipids

“…Analyses for the corresponding plasma specimens were in general agreement with previously published findings for this source (Horgan and Masters 1963). …”

“…The high oleic acid content of ovine erythrocytes (Table 1; Kogl et al 1960) is unusual when the saturated character of most ruminant lipids are compared (Horgan and Masters 1963;Masters 1964c), and in view of the low oleic acid content in erythrocytes from monogastric animals (Veerkamp et al 1962). Examination of the results shows that this acid is located predominantly in the phospholipid fraction (Table 1), which contains the highest level ofthis acid in all the major owe tissues (Horgan and Masters 1963;Masters 1964c).…”

“…Examination of the results shows that this acid is located predominantly in the phospholipid fraction (Table 1), which contains the highest level ofthis acid in all the major owe tissues (Horgan and Masters 1963;Masters 1964c). Possibly this is a factor contributing to the peculiar properties of the ruminant erythrocyte membrane (Rapaport and Guest 1941;Dawson et al 1960).…”

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As part of a study of comparative lipid metabolism, the distribution of fatty acids has been investigated in a number of mammalian tissues (Horgan and Masters 1963;Masters 1964aMasters , 1964bMasters , 1964cConnellan and Masters 1965), a major aim of these studies being to facilitate correlation between lipid composition and function. In this context, it is widely recognized that membranes playa fundamental role in cellular metabolism, and that lipid is an essential component of these biomembranes (Stein and Danielli 1956).

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“…After each centrifugation, the upper layer of cells (containing leucocytes and thrombocytes) was removed and discarded. The lipids were then extracted from the erythrocytes and the corresponding plasma specimens, fractionated on silicic acid columns, and the fatty acids determined by gas chromatography.These techniques have been fully described previously (Horgan and Masters 1963). …”