Polyunsaturated Fatty Acids In Tissues Research Articles

Levels of polyunsaturated fatty acids in tissues from zinc-deficient rats fed a linseed oil diet.

The effect of zinc deficiency on the levels of n-6 and n-3 polyunsaturated fatty acids (PUFA) in lipids from tissues of rats fed a diet containing linseed oil was investigated. Rats were fed either a control diet (25 mg Zn/kg) or a zinc-deficient diet (0.8 mg Zn/kg) for 10 d. To avoid energy and nutrient deficiency, 11.6 g of diet per day was administered by gastric tube. At the end of the experiment, rats fed the zinc-deficient diet had drastically reduced plasma zinc concentration and alkaline phosphatase activity consistent with severe zinc deficiency in these rats. Zinc-deficient rats had higher levels of n-3 PUFA, in particular eicosapentaenoic acid (EPA), and lower levels of n-6 PUFA, in particular linoleic acid, in liver and plasma phosphatidylcholine (PC) and in erythrocyte membrane total lipids than did control rats. By contrast, the levels of n-3 PUFA in PC from testes and heart, and in phosphatidylethanolamine (PE) from liver, testes and heart, were only slightly different between zinc-deficient and control rats. The study suggests that desaturation of alpha-linolenic acid is not inhibited by zinc deficiency, and that in zinc-deficient rats, n-3 PUFA preferentially incorporated into phospholipids at the expense of n-6 PUFA, especially EPA into PC. The study also shows that the effect of zinc deficiency on PUFA levels is different for PC and PE in rat tissues.

Polyunsaturated dietary lipids lower the selected body temperature of a lizard.

Cold acclimation lowers the selected body temperature (Tb) in many ectothermic vertebrates. This change in behavioural thermoregulation is accompanied by an increase in the proportion of polyunsaturated fatty acids in tissues and cellular membranes. We investigated how diets containing different fatty acids, known to significantly alter the fatty acid composition of animal tissues and membranes, affect the selected Tb of the lizard Tiliqua rugosa. Lizards on a diet containing many polyunsaturated fatty acids (10% sunflower oil) showed a 3-5 degrees C decrease in Tb, whereas Tb in animals on a diet containing mainly saturated fatty acids (10% sheep fat) did not change. Our study suggests that the composition of dietary lipids influences thermoregulation in ectothermic vertebrates and may thus play a role in the seasonal adjustment of their physiology.

Impact of dietary fatty acid supplementation on renal injury in obese Zucker rats

We previously reported that renal injury in hyperlipidemic, obese Zucker rats was associated with a relative deficiency of tissue polyunsaturated fatty acids (PUFA). In the present study 10-week-old obese Zucker rats were pair fed regular chow or chow containing either 20% sunflower oil rich in n-6 PUFA, fish oil rich in n-3 PUFA, coconut oil medium-chain saturated fatty acid, or beef tallow long-chain saturated fatty acid. At 34 weeks of age there were comparable reductions in albuminuria, mesangial matrix expansion, and glomerulosclerosis in the fish oil and sunflower oil groups. While both fish oil and sunflower oil reduced serum triglycerides, and improved the composition of triglyceride-enriched lipoproteins, only fish oil decreased serum cholesterol. The effect of the dietary fatty acid supplementation on fatty acid profiles were similar in isolated glomeruli and cortical tissue. In general, the amelioration in injury in the fish oil and sunflower oil fed rats was most closely linked to glomerular levels of PUFA, either n-6 or n-3. These data suggest that hyperlipidemia and abnormalities in tissue FA are closely linked, and that dietary supplementation with PUFA may ameliorate chronic, progressive renal injury.

Polyunsaturated fatty acids in tissues of rats fed trielaidin and high or low levels of linolenic acid

Male and female weanling rats that were born to dams fed a diet low in linolenic acid received diets of 15% lipids by weight containing 45% elaidic acid (as trielaidin) and 8.5% or 0.1% linolenic acid for 10 weeks. Four other groups, in which palmitic or oleic acid replaced elaidic acid in the diet, served as controls. The fatty acid profiles of several lipid classes were determined in adipose tissue, adrenals, testes, heart and brain. Elaidic acid was incorporated into tissue lipids in varying degrees, depending on the organ and on the lipid class. Feeding elaidic acid induced no changes in the polyunsaturated fatty acid (PUFA) profiles of testes lipids but resulted in definite modifications of the PUFA patterns of heart phosphatidylcholine (PC) and phosphatidylethanolamine (PE). In linolenic acid-deprived rats, arachidonic acid was decreased in PC and linoleic acid was increased in both PC and PE; 22:5n-6 was strongly depressed in both PC and PE. In linolenic acid-fed rats, 22:6n-3 was decreased in PC and PE. These changes, on the whole, were more evident in females, and some also were observed in adrenal cholesteryl esters but only slightly in brain phospholipids. The apparent inhibition of the biosynthesis of PUFA induced by dietary elaidic acid appeared to be complex and of greater intensity in the n-6 fatty acid series than in their n-3 homologues.

The inhibition of lipid autoxidation by human serum and its relation to serum proteins and alpha-tocopherol.

1. The inhibitory (antioxidant) effect of serum on the autoxidation of tissue polyunsaturated fatty acids has been investigated. 2. Dialysis studies, DEAE-cellulose chromatography, gel filtration, immunoelectrophoresis and immunodiffusion experiments showed that this effect is the function of two serum protein fractions. 3. One fraction was identified as transferrin. The second fraction includes caeruloplasmin. 4. Studies with radioactively labelled α-tocopherol showed that serum tocopherol in the physiological concentration range contributes only marginally to the total antioxidant activity of serum. 5. These findings are discussed in the wider context of biological antioxidant protection.

Oxidation of unsaturated fatty acids by ozone and nitrogen dioxide. A common mechanism of action.

Trace quantities of ozone and nitrogen dioxide, 1.5 ppm, catalyzed the rapid oxidation of unsaturated fatty acids. Nitrogen dioxide-catalyzed oxidations were dependent upon the NO2 concentration in the atmosphere. Both thin films and aqueous emulsions of fatty acids are oxidized by NO2 through a mechanism akin to the spontaneous autoxidation in air. Phenolic antioxidants, including vitamin E, retarded the oxidation. Ozone catalyzed a more rapid and complete oxidation than NO2 by a direct attack upon the double bonds of the fatty acid. Phenolic antioxidants are protective only in aqueous emulsions where the oxidation proceeds by peroxidation as well. Oxidation of essential tissue polyunsaturated fatty acids by O3 and NO2 is a likely common mechanism of toxicity.

Lipid peroxidation in vivo.

AbstractUnder a rather rigidly defined set of empirical conditions, the kinetics of production of a specific tocopherol‐deficiency sign, creatinuria, in the rat were comparable to the kinetics of the autoxidation of pure polyunsaturated fatty acids in model systemsin vitro. The tocopherol requirement of the rat under these conditions was clearly related to the kinetics of lipid peroxidation. Dietary, biologically available selenium decreased the rate of production of creatinuria and the rate of disappearance of tissue polyunsaturated fatty acids (PUFA) equally and, therefore, may have functioned as a lipid antioxidantin vivo. A hypothetical model of lipid peroxidation was prepared in an attempt to describe the interaction of PUFA, tocopherol, biologically available selenium, and sulfur amino acids.

The influence of dietary fatty acids and environmental temperature on the fatty acid composition of teleost fish

AbstractMarine and fresh water fish were depleted of tissue unsaturated fatty acids to various degrees and subsequently presented with linoleic and linolenic acids at different dietary levels, at different temperatures, with and without other dietary fat.Examination of the tissue fatty acids demonstrated that marine and fresh water fish do not differ between themselves or from other classes of animals in the following basic mechanisms of deposition and interconversions of dietary fatty acids: The fish are readily depleted of tissue polyunsaturated fatty acids. Dietary linoleic and linolenic acids are deposited, the former to a greater degree than the latter. At high levels of linoleic or linolenic acids in the diet there is no significant degree of their conversion to the longer chain more highly unsaturated acids typical of marine oils. At low levels of linoleic or linolenic acids in the tissues there is a significant, but slight, conversion to the longer chain acids at low environmental temperatures. The increase in the level of linoleic acid in tissue lipids which accompanies increases in the dietary levels, quickly tapers off above dietary levels of 5%. Temperature differences between 13 and 23C had little or no influence on the deposition or interconversion of polyunsaturated acids. Dietary cottonseed oil, which contains cyclopropene fatty acids, produces an increase in tissue stearic acid in the fundulus.

Polyunsaturated fatty acids in tissues of growing male and female rats

Polyunsaturated fatty acid concentrations of tissues were determined in male and female Sprague-Dawley rats of weanling, 3 months, and 6 months of age. No significant differences were found in concentrations of polyunsaturated fatty acids in corresponding tissues of male and female animals. Concentrations of polyunsaturated fatty acids in tissues of rats changed with age. The changes were different for each tissue and varied with the polyene concerned. Hexaenes comprised the greatest portion of polyunsaturated fatty acids in the brain of rats while dienes predominated in muscle and pentaenes in the testes. Tetraenes were in uniformly high concentrations in all organs and tissues studied and varied less with age than any of the other polyenes. Brain differed from other tissues in that it contained only trace amounts of dienes but relatively large quantities of tetraenes. In all tissues except brain a marked decrease was observed in hexaene concentration as animals matured from weanling to 6 months of age. Many of the tissues had lower tetraene and pentaene levels at 3 months than at either weanling or 6 months. The most marked change with age was the large increase in pentaene levels of testicular tissue between the ages of 3 weeks and 3 months.