Triglyceride and Free Fatty Acid

The flux of glucose and its metabolites in adipocytes is depicted in Fig. 6.7c. The uptake and phosphorylation follow the same rules as for muscle [62], so Eqs. (29) and (30) are assumed valid for the adipocytes also. They can also build glycogen, but the amount is believed to be small [62]. The main part of the incoming glucose is therefore converted to lactate or used for lipogenesis. Only a small part is oxidized. 

The destiny of ingested fat is shown in Fig. 6.15. The ingested triglyceride (TG) is broken down in the intestine to fatty acids (FAs) and glycerol or monoglycerides [74]. Inside the intestinal cell, the TG is rebuilt and released to the lymph as chylomicrons that later reaches the blood [74]. The TG in the chylomicrons is again broken down to FAs and glycerol by lipoprotein lipase (LPL) in the vessel wall [74]. The FAs are either released to plasma - the so-called spill over [97] - or transported into the adipocytes, rebuilt to TG and stored [74, 97]. 

FAs in plasma - the so-called free fatty acids (FFA) although they are bound to albumin [74] - stem mainly from lipolysis inside the adipocytes and spill-over from the LPL lipolysis [98]. FFA can be taken up and oxidized by most cells, particularly muscle cells [74]. For example the heart lives mainly on fat oxidation [62, 74]. Also the liver takes up FFAs. Some is oxidized, but a large fraction is rebuilt to TG and released to blood as very low density lipoproteins (VLDLs) [74]. The VLDLs undergo the same fate as chylomicrons, but their lipolysis rate is lower. 

An important role of the insulin-glucose control system is therefore to shuffle the ingested nutrients between storing, releasing, and oxidation to smoothen the transitions between eating-fasting and exercise-rest, etc. 

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Finally, dyslipidemia is a feature of FXR knockout mice levels of VLDL, LDL and HDL cholesterol and ApoB lipoproteins are increased concomitant with reduced clearance of HDL cholesteryl ester and elevated triglyceride and free fatty-acid levels. ... 

Chromarod FID peaks of sterols, diglycerides, monoglycerides, and polar lipids are narrower and sharper than peaks of triglycerides and free fatty acids when analyzed using either method described in this unit (see Basic Protocol and Alternate Protocol). Hydrogenation of total lipids (see Support Protocol) results in much sharper and narrower peaks, which in turn substantially improves the resolution between lipid classes. The accuracy and precision in quantitating lipid classes of vegetable oils and animal fats are expected to be better than those from marine lipids. 

The sequence of events in which triglycerides and free fatty acids or derivatives are involved in the oxidation process has been studied by many researchers. The... 

II. Plasma glucose, Triglyceride, and Free Fatty Acids Assay... 

Table 3 Effect of plasma glucose, triglyceride, and free fatty acids in obese diabetic mice treated with Entry 1 at lOmg/kg per day...

Wittwer CT, Beck S, Peterson M, Davidson R, Wilson DE, and Hansen RG (1990) Mild pantothenate deficiency in rats elevates serum triglyceride and free fatty acid levels. Journal of Nutrition 120,719-25. 

The four major plasma lipid fractions (phospholipids, cholesteryl esters, triglycerides, and free fatty acids) exhibited similar changes in response to the fish-oil diet. In the phospholipid fraction, the n-3 fatty acids increased from 0.4% to 34% of total fatty aicds in the fish oil diet. EPA increased from 0% to 19%, accounting for 55 percent of the total increase. Linoleic acid reciprocally decreased from 36% to 5% and total n-6 fatty acids from 48% to 12% of total fatty acids. In cholesteryl esters, n-3 fatty acids increased from 0.2% to 36%. An increase in EPA from 0% to 31% accounted for 86% of the increase, a much greater proportion than in phospholipids, whereas DHA only increased from 0% to 4%. The decline in n-6 fatty acids from 77% to 23% was largely accounted for by a decrease in linoleic acid from 73 % to 17%. Similar changes were seen in the triglycerides and free fatty acid fractions. 

Shapiro el al. (1960) studied the distribution of labeled fatty acids in the triglycerides synthesized by rat mesenteric fat incubated with palmitate-1-C and concluded that the newly synthesized triglycerides primarily resulted from a process involving the total esterification of a-glycerophosphate with 3 molecules of fatty acid, and that esterification of preformed tissue diglycerides, or a lipase-activated exchange between triglycerides and free fatty acid did not make a major contribution. 

Fig. 1. Concentration of cardiac triglycerides and free fatty acids in rats fed HEAR oil or corn oil at 20% by weight of the diet for up to 16 weeks. Data for 0 to 3 days were taken from Kramer and Hulan (1978b) and the remaining values from Kramer et a/. (1979b).

Another fatty acid which is correlated to heart lesions is docosenoic acid (22 1). Apart from the accumulation of 22 1 in the cardiac triglycerides and free fatty acids, 22 1 is also incorporated into the cardiac phospholipids in decreasing order of SP > DPG > PE — PC (Section lll,C,2.). Generally, the 22 1 is incorporated into position 2 of cardiac PE and PC, a position normally occupied by 18 2 n-6 and 20 4 n-6. In this position 22 1 may possibly interfere with prostaglandin formation, although this appears unlikely from... 

Some results for the effects of addition of different lipid compounds on loaf volume of a base flour are shown in Figure 7.10 (Sroan 2007). The natural lipid from flour has been separated into two fractions polar and nonpolar. Thin layer chromatography (TLC) of the fractions is shown in Figure 7.11. Polar lipids comprise mainly galactolipids and phospholipids. Their addition enhances loaf volume. In contrast, the nonpolar fraction, which comprises mono-, di-, and triglycerides and free fatty acids as the main components, causes depression of the loaf volume. The unsaturated linoleic acid, which is the major fatty acid in wheat, also depresses loaf volume, whereas the saturated palmitic acid has no effect. Another saturated fatty acid, myristic acid, affected loaf volume negatively. 

Figure 7.11 TLC patterns for (1) total flour lipid and its (2) polar and (3) nonpolar fractions. Polar lipids comprise phospholipids and galactolipids. The nonpolar fractions include mono-, di-, and triglycerides and free fatty acids.

White and Houck Oligoethers, triglycerides and free fatty acids Capillary column 19 m x 100/ m DB-5, 5m X lO/im DB-225 Carbon dioxide FID Pressure programming... 

The chromatogram-like structure of the carbonyl region shows separation of a mixture from different mono-, di- and triglycerides and free fatty acids (Fig. 4.7). This method is used for quality control of olive oils (Sacchi et al, 1990). Integrals of the respective intensities are directly proportional to the molar amount of the component, with one restriction comparison is only allowed between atoms in the same chemical environment, for example carbonyls only with carbonyls, methyls only with methyls and so on. There is no need for a standard to evaluate the fatty acid distribution, and no calibration and no quality control samples are needed. No chemical modification such as saponification or derivatization is necessary, so degradation of the chemically sensitive polyunsaturated acids is avoided. The material can be recovered unchanged after the measurement. In addition to the general fatty acid distribution a determination of individual distributions is possible. ... 

ScHLiBRF and Wood [140] have carried out semi-quantitative determination of the triglycerides and free fatty acids in serum after thin-layer chromatographic separation on silica gel G it was based on the linear relation between the square root of the area of the substance spot and the logarithm of the amount of substance. The reproducibility of replicate determinations on the same serum was good, with a standard deviation of 8.1—8.5%. The method is complicated in relation to the limited information yielded. 

Two ml edible oil was administered to intact rats orally in the presence or absence of DIMES. The absorption process was followed by measuring the plasma triglyceride and free fatty acid concentration, as demonstrated in Figure 2. 

In acute severe systemic intoxication abnormalities of routine clinical chemistry are usually present such as metabolic acidosis, increased anion gap, cytopenia, hypoglycemia, hyperammonemia (which can mask acidosis), lactic acidemia, elevations of triglycerides and free fatty acids, and ketosis. Testing for ketonuria is an especially simple and useful first line investigation. In most newborns as well as in older children with organic acid disorders, including some patients with fatty acid oxidation defects, there is pronounced ketonuria. Ketonuria is only rarely observed even in very sick newborns without metabolic disease. 

Gousios, A., J. M. Felts, and R. J. Havel The metabolism of serum triglycerides and free fatty acids by the myocardium. Metabolism 12, 76 (1963). 

Additional stndies have been conducted on the extraction of triglycerides and free fatty acids nsing SC-CO2 alone. Typically, an inCTease in pressure increases oil extraction yield and operating pressure has the greatest impact on oil yield. This is confounded by tanperature. An increase in extraction tanperature increases the oil extraaion yield at high pressure. With lower pressure, an increase in extraction tanperature lowers the oil extraction yield (Dunford and TemeUi, 1997 Fattori et al., 1988). Table 8.1 summarizes selected SC-CO2 operating parameters for extraction/ fractionation of oil and components from canola and oilseed rape. 

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