No abstract

Effects of diets containing mixtures of safflower oil, hydrogenated coconut oil with elaidate of linolelaidate on growth, fatty acid composition, serum lecithin: cholesterol acyl transferase (LCAT) and postheparin plasma lipoprotein lipase activities in essential fatty acid (EFA) deficient rats were determined. Addition of trans fatty acids to the diet lowered the growth response to linoleic acid. Both elaidate and linolelaidate accumulated in the serum and liver, imparied the conversion of oleic acid to eicosatrienoic acid and linoleic acid to arachidonic acid, and the incorporation of eicosatrienoic acid into cholesteryl esters. Trans fatty acids also influenced the fatty acid composition of testicular lipids, but much lower amounts of these acids accumlated in tests than in liver or serum. Serum lecithin:cholesterol acyl transferase activity was elevated by an EFA deficiency, was unaffected by dietary elaidate, but was significantly decreased by linolelaidate. These effects were nullified by the addition of safflower oil to the diet. Postheparin plasma extrahepatic and hepatic lipase activities were also affected by an EFA deficiency, and by the addition of elaidate or linolelaidate alone or in combination with safflower oil to the diets of EFA deficient rats. It is suggested that trans fatty acids exhibit particular effects on the metabolism of lipids in addition to aggravation of an EFA deficiency.

Techniques for the quantitative analysis of lipids using thin‐layer chromatography (TLC) are reviewed. The general procedures are divided into two groups on the basis of whether or not the methods involve the recovery of substances from chromatoplates. Recovery methods are elaborated under detection of spots, recovery of substances and quantification. Methods are described for the recovery of labile compounds from chromatoplates and for the determination of the structures of triglycerides and lecithins. Methods for the direct quantitative analysis of spots on chromatoplates are reviewed. These include measurements of spot size, reflectance, absorbance of transmitted light, and fluorescence. Details of the photodensitometric method, particularly, spot visualization and instrumentation are described. The analysis of lipid classes using a combination of DEAE cellulose chromatography and TLC by the densitomery of charred spots is illustrated.