Tissue manganese levels and liver pyruvate carboxylase activity in magnesium-deficient rats

To investigate the manganese status in magnesium deficiency, 40 male Wistar rats, 3 wk old, were divided into two groups and fed a magnesium deficient diet or a normal synthetic diet for 2 wk. Dietary magnesium depletion decreased magnesium levels in brain, spinal cord, lung, spleen, kidney, testis, bone, blood, and plasma, while it elevated the magnesium level in liver. In magnesium-depleted rats, calcium concentration was increased in lung, liver, spleen, kidney, and testis, while it was decreased in tibia. In magnesium-depleted rats, manganese concentration was decreased in plasma and all tissues except adrenal glands and blood. Dietary magnesium depletion diminished pyruvate carboxylase (EC 6.4.1.1) activity in the crude mitochondrial fraction of liver. Positive correlation was found between the liver manganese concentration and the pyruvate carboxylase activity. In the magnesium-depleted rats, glucose was decreased while plasma lipids (triglycerides, phospholipids, and total cholesterol) were increased. These results suggest that dietary magnesium deficiency changes manganese metabolism in rats.     

Effect of Intramuscular Administration of Retinol on Plasma Lipids of Rats

The effect of intramuscular administration of 100,000 I. U. of retinol daily for 13 days on plasma lipids of young rats has been studied. Significant elevations in the plasma total lipids, phospholipids and glycerides were noted in retinol treated rats as compared to control rats. Although significant elevations were noted in plasma phospholipids, the percentage distribution of plasma phospholipid components was unaffected in retinol treated rats as compared to control group.     

Hypolipidemic effect of methanolic extract of Dolichos biflorus Linn. in high fat diet fed rats

High fat diet fed rats showed significant increased levels of plasma and tissue total cholesterol, triglycerides, free fatty acids, phospholipids, plasma LDL cholesterol and decreased level of plasma HDL cholesterol. Methanolic extract of D. biflorus administration to high fat diet fed rats showed near to normal levels of the above lipids in plasma and tissues. Higher dose of the extract (400 mg/kg body weight) showed comparable results with standard drug atorvastatin. It is concluded that the methanolic extract of D. biflorus possesses hypolipidemic activity in high fat diet fed rats.     

Changes in the components of biliary and plasma lipids in selenium-deficient rats

We constructed a chronic oxidative stress model in which Se-deficient diet was fed to male Wister rats for 8 weeks. As expected, effects of oxidative damage, including Fe accumulation and increase in peroxidized lipids, were identified in the liver owing to the lack of glutathione peroxidase. Although the oxidative stress caused Fe accumulation in the liver, the Fe concentration in bile of the SeD rat was almost the same as that in the control rats. The constant excretion of Fe into bile supported the Fe accumulation in the liver. No differences were observed in the principal components of biliary lipids, i.e., bile acids, phospholipids, and cholesterol, between the two groups; moreover, these trends were also reflected in the plasma. Due to the trapping of reactive oxygen species, only bilirubin concentrations in the bile and plasma were decreased in the SeD group, when compared with those in the control group. Measurement of bilirubin concentration may be used as a supplemental oxidative stress marker.     

Effect of essential fatty acid deficiency on the lipid composition of the Yoshida ascites hepatoma (AH 130) and of the liver and blood plasma from host and normal rats.

In order to study the response of a poorly differentiated tumor to nutritional manipulation, the Yoshida ascites hepatoma (AH 130) was grown in rats fed an essential fatty acid (EFA)-deficient diet and in rats fed a control diet. Hepatomas, livers, and blood plasma from host rats and normal rats were studied as to the effects of EFA deficiency on the lipid composition. Normal rats fed an EFA-deficient diet showed an increased concentration of triglycerides and cholesteryl esters in the liver and a reduced level of total phospholipids in plasma. Host rats fed the EFA-deficient diet showed a lower concentration of triglycerides in the liver when compared with the host rats fed a control diet. In addition, EFA-deficient host rats had reduced levels of plasma free fatty acids and triglycerides. These latter were markedly high in host rats under normal dietetic conditions. As compared to the livers of either host rats or normal rats fed the control diet, the Yoshida hepatoma cells had a lower content of total phospholipids and free fatty acids as well as a higher level of free cholesterol; they also showed a typical fatty acid pattern in their phospholipids. The main characteristics of this pattern were a high content of oleic and palmitoleic acids and a low level of C20 and C22 polyunsaturated fatty acids. Exposure of Yoshida hepatoma cells to an EFA-deficient environment resulted in a decrease in the concentration of total phospholipids and free fatty acids and in changes in the fatty acid composition similar to those observed in the livers of normal and host rats. These changes suggest that, under the experimental conditions used, the Yoshida hepatoma cells are responsive to EFA deficiency.     

Beneficial effects of alpha linolenic acid rich flaxseed oil on growth performance and hepatic cholesterol metabolism in high fat diet fed rats

The purpose of the study was to investigate the effect of flaxseed oil (FO), rich in alpha-linolenic acid (ALA) (18:3 n-3) on growth parameters and lipid metabolism of rats fed with high fat diet. High fat diet (HFD) resulted in significant alterations in hepatic lipids, increase in body weight gain and negative effect on lipoprotein metabolism. FO supplementation significantly lowered the increase in body weight gain, liver weight, plasma cholesterol, triglycerides, phospholipids, free fatty acids, high-density lipoprotein (HDL), low-density lipoprotein-cholesterol (LDL-C), very low-density lipoprotein (VLDL), LDL/HDL and TC/HDL ratio in HFD fed rats. FO significantly reduced the hepatic and plasma lipid levels indicating its hypolipidemic activity. On the other hand, oral administration of FO exhibited lower plasma lipoprotein profile as compared to HFD rats. Hepatic protection by FO is further substantiated by the normal liver histological findings in HFD fed rats. These data suggest that FO participate in the normal regulation of plasma lipid concentration and cholesterol metabolism in liver. No adverse effect of FO on growth parameters and plasma lipids in rats fed with fat-free diet. The results of the present study demonstrate that FO may be developed as a useful therapy for hyperlipidemia through reducing hepatic lipids, thereby proving its hypolipidemic activity.     

The effect of dietary menhaden,olive, and coconut oil fed with three levels of vitamin E on plasma and liver lipids and plasma fatty acid composition in rats

The effect of dietary fats with varying degrees of unsaturation in the presence of different concentrations of vitamin E on tissue lipid levels was studied in rats. Rats were fed either menhaden oil, olive oil or coconut oil at 15% levels with either 0.1, 0.3 or 0.6 mg/g of vitamin E as alpha-tocopherol for four weeks. Rat serum and liver were analyzed for total cholesterol, HDL-cholesterol, triacylglycerol and phospholipids. In addition, fatty acid composition of serum lipids was also analyzed. Serum total cholesterol and triacylglycerol were significantly lower in rats fed menhaden oil than in those fed olive or coconut oil, while the HDL-cholesterol was significantly higher in serum of rats fed menhaden and olive oil than in those fed coconut oil. Levels of vitamin E in the diet had only a significant effect on serum cholesterol and liver phospholipids. The Pearson correlation coefficient showed a significant positive relationship between serum triacylglycerol and total cholesterol, and a negative correlation between triacylglycerol and HDL-cholesterol, and between total and HDL-cholesterol.In the liver, total cholesterol was significantly higher in rats fed coconut oil than in rats fed menhaden oil. Total liver phospholipids were lower in rats fed either coconut oil or olive oil compared to those fed menhaden oil, especially with higher levels of vitamin E intake. Higher levels of vitamin E in the diet appear to increase triacylglycerol and phospholipids in livers of rats fed menhaden oil. In the liver a significant negative correlation was observed between phospholipids and cholesterol. The type and degree of unsaturation (polyunsaturated fatty acids in menhaden oil, monounsaturated fatty acids in olive oil and saturated fatty acids in coconut oil) significantly affected plasma and tissue lipids.     

Lipid metabolism in fatty liver of lysine- and threonine-deficient rats

Rats were fed a low protein diet deficient in and supplemented with lysine and threonine. Liver lipids contained more lecithin, sphingomyelin, and free fatty acids, and less amino phospholipids in the deficient rats. No variations in fatty acid composition of choline- and ethanolamine-containing phospholipids were found; only palmitic acid was increased in the serine-containing phospholipids of the deficient animals. The incorporation of acetate-(14)C into phospholipids, but not into other liver lipids, was lower in deficient rats. In the plasma of deficient rats the concentration of esterified fatty acids and phospholipids was lower, of free fatty acids higher, than in the controls. The fatty acid composition of depot fat differed from that of liver neutral fat both in deficient and supplemented animals. The results presented establish that multiple metabolic defects resulting from lysine and threonine deficiency accompany the fatty liver. The design of the experiments does not permit conclusions to be drawn regarding the causal relationship between the various alterations in lipid metabolism and the fatty liver.     

Effect of ovariectomy and replacement therapy on the tissue lipid pattern in rats.

Ovariectomy increases the percentage of total lipids in liver, kidney and uterus of intact cyclic rats. Estrogen and progesterone, when administered individually to ovariectomized rats, caused a decrease in the total lipid content of all tissues. Th effect of progesterone in estrogen-primed rats is not significant. Triglyceride and cholesterol content increases after ovariectomy; treatment with estrogen in ovariectomized rats led to a decrease in the concentration of these lipids. Progesterone has no significant effect on these lipids but showed an antagonistic action when given in estrogen-primed ovariectomized rats. The proportions of ethanolamine, choline and inositol phospholipids decreased after spaying and increased when estrogen was given to spayed rats. Progesterone alone had effect only on the uterus whereas progesterone administered to estrogen-primed rats showed an antagonistic effect in all tissues.     

Effect of low dietary rubidium on plasma biochemical parameters and mineral levels in rats

The effects of low dietary rubidium on plasma biochemical parameters and mineral levels in tissues in rats were studied. Eighteen male Wistar rats, weighing about 40 g, were divided into two groups and fed the diets with or without supplemental rubidium (0.54 vs 8.12 mg/kg diet) for 11 wk. Compared to the rats fed the diet with supplemental rubidium, the animals fed the diet without rubidium supplementation had higher urea nitrogen in plasma; lower rubidium concentration in tissues; lower sodium in muscle; higher potassium in plasma, kidney and tibia, and lower potassium in testis; lower phosphorus in heart and spleen; lower calcium in spleen; higher magnesium in muscle and tibia; higher iron in muscle; lower zinc in plasma and testis; and lower copper in heart, liver, and spleen, and higher copper in kidney. These results suggest that rubidium concentration in tissues reflects rubidium intake, and that rubidium depletion affects mineral (sodium, potassium, phosphorus, calcium, magnesium, iron, zinc, and copper) status.     

Restoration of antioxidants in liver by methionine feeding in experimental rat urolithiasis.

The effect of methionine or citrate on antioxidant defense system has been studied in urolithic rat. Liver weight and its protein concentration did not change in the rats fed with calculi producing diet (CPD) when compared to normal diet fed rats. Feeding rats along with citrate (c-CPD) or methionine (m-CPD) improved their body weight gain. Liver microsomes and mitochondria fractions of CPD and c-CPD fed groups showed increased susceptibility for lipid peroxidation in presence of ascorbate and t-butyl hydroperoxide when compared to either control or m-CPD fed groups. Increased superoxide dismutase and xanthine oxidase activities, decreased catalase, glutathione peroxidase and glucose-6-phosphate dehydrogenase activities, decreased concentrations of reduced glutathione, total thiols, ascorbic acid and vitamin-E and increased formation of hydroxyl radical, hydroperoxides and diene conjugates were observed in the liver of both CPD fed group as well as c-CPD fed group. Except SOD and xanthine oxidase, all other parameters were normalized in m-CPD fed group. This suggested that feeding methionine reduced the susceptibility for lipid peroxidation by restoration of the level of free radical scavengers.     

Effect of n-6 and n-3 dietary fatty acids on phospholipid composition of plasma, platelets and aorta in the rat

Female Wistar rats were fed with diets containing as dietary lipids 10% of hydrogenated coconut oil, grape-seed oil, olive oil, linseed oil and fish oil, respectively, for a period of 60 days. At the end of dietary treatment plasma, platelets and aorta phospholipids were extracted and fatty acid spectra determined. Plasma and platelet phospholipids showed the largest diet dependent changes. Anyway in aorta samples too, phospholipids showed marked increase in oleic (olive oil group) linoleic (grape-seed oil group) and alpha linoleic (linseed oil group) acids percentage. Conversely decreased amounts of arachidonic acid were detected in rats fed with diets containing linseed and fish oils. In these samples eicosapentenoic acid partly replaced arachidonic one.     

Effect of dietary iron deficiency on mineral levels in tissues of rats

To clarify the influence of iron deficiency on mineral status, the following two synthetic diets were fed to male Wistar rats: a control diet containing 128 micrograms iron/g, and an iron-deficient diet containing 5.9 micrograms iron/g. The rats fed the iron-deficient diet showed pale red conjunctiva and less reactiveness than the rats fed the control diet. The hemoglobin concentration and hematocrit of the rats fed the iron-deficient diet were markedly less than the rats fed the control diet. The changes of mineral concentrations observed in tissues of the rats fed the iron-deficient diet, as compared with the rats fed the control diet, are summarized as follows: . Iron concentrations in blood, brain, lung, heart, liver, spleen, kidney, testis, femoral muscle, and tibia decreased; . Calcium concentrations in blood and liver increased; calcium concentration in lung decreased; . Magnesium concentration in blood increased; . Copper concentrations in blood, liver, spleen and tibia increased; copper concentration in femoral muscle decreased; . Zinc concentration in blood decreased; . Manganese concentrations in brain, heart, kidney, testis, femoral muscle and tibia increased. These results suggest that iron deficiency affects mineral status (iron, calcium, magnesium, copper, zinc, and manganese) in rats.     

Free Radical-Induced Liver Injury. I. Effects of Dietary Vitamin E Deficiency on Triacylglycerol Level and its Fatty Acid Profile in Rat Liver

Effects of dietary vitamin E deficiency on the fatty acid compositions of total lipids and phospholipids were studied in several tissues of rats fed a vitamin E-deficient diet for 4, 6, and 9 months. No significant differences were observed between the vitamin E deficiency and controls except in the fatty acid profiles of liver total lipids. Triacylglycerol (TAG) accumulation was found in the liver of rats fed a vitamin E-deficient diet. The levels of TAG-palmitate and -oleate increased particularly in the liver from such animals. The fatty acid compositions of hepatic phospholipids were not affected by the diet. Increased TAG observed in the liver of rats fed a vitamin E-deficient diet was restored to normal when the diet was supplemented with 20 mg α-tocopheryl acetate/kg diet. These findings indicate that dietary vitamin E deficiency causes TAG accumulation in the liver and that the antioxidant, vitamin E, is capable of preventing free radical-induced liver injury.     

Effects of Sterylglycosides from Soybean on Lipid Indices in the Plasma,Liver, and Feces of Rats

The effects of soybean oil (SOO, control), soybean lecithin (SOL), and of sterylglycocides (STG) and phospholipids (PL) fractionated from SOL on lipid indices in the plasma, liver, and feces were examined for male Wistar rats fed with diets containing these lipids for 3 weeks. The body weight gain and liver weight decreased or tended to be reduced in the animals given the diet containing a 5% STG mixture (STGM) compared with the values in the other dietary groups. The plasma lipid concentration in general declined in the rats fed with the diets supplemented with 5% SOL, STGM, or the PL mixture (PLM), and with 1% of STGM, acylated STG (ASTG), or non-acylated STG (NSTG). The triacylglycerol level was significantly depressed in the rats fed with the diets including 1 or 5% of STGM, ASTG, or NSTG when compared to the level of the SOO—fed animals. The total cholesterol and triacylglycerol contents in the liver were lower in the rats provided with the diets containing 5% of SOL, PC, or PLM than in the SOO- or STGM-diet-fed animals. The rats given the diets supplemented with 1 or 5% of STGM, ASTG, or NSTG had a decreased content of liver triacylglycerol compared with the content of the SOO—fed animals. The amounts of total lipids and total cholesterol excreted into the feces were higher in the rats fed with the diets supplemented with 5% SOL, or with 1% of STGM, ASTG, or NSTG, or especially with 5% STGM than in the SOO—fed animals. The present results suggest that STG suppressed the absorption of cholesterol and fatty acids in the intestines.     

Effect of citrate feeding on free radical induced changes in experimental urolithiasis.

Feeding calculi producing diet (CPD) to rats for 4 weeks produced calcium oxaltate stones. Supplementation of sodium citrate to CPD (c-CPD) prevented stone formation. Except oxalate, the excretion of calcium, phosphorus and magnesium was restored to normal in c-CPD fed rats. The CPD fed rats exhibited increase in glycolic acid oxidase (GAO) and lactate dehydrogenase (LDH) activities and only GAO activity was partially restored in c-CPD fed rats. Kidney sub-cellular fractions of calculi producing diet (CPD) fed rats showed increased susceptibility for lipid peroxidation in presence of promotors. Antioxidant enzyme activities of superoxide dismutase (SOD), catalase and glutathione peroxidase and antioxidant concentrations of reduced glutathione, total thiols, ascorbic acid and vitamin E were significantly decreased while the xanthine oxidase activity, and concentrations of hydroxyl radical, diene conjugates and hydroperoxides were significantly increased in CPD fed rats. The susceptibility to lipid peroxidation, activities of antioxidant enzymes, and the concentration of antioxidants were not normalized by feeding citrate.     

Bioavailability of the isomer mixture of phytoene and phytofluene-rich alga Dunaliella bardawil in rat plasma and tissues

Dunaliella bardawil, a beta-carotene-accumulating alga was treated by the bleaching herbicide norflurazon to select sub-species rich with a mixture of 9-cis and all-trans stereoisomers of phytoene and phytofluene. The present study determines the bioavailability of phytoene and phytofluene with their stereoisomers in rats fed on a diet supplemented with Dunaliella phytoene-rich spray dried powder. Three groups of female weanling rats, eight animals each, were fed AIN diets for two weeks. The control consumed the diet as is. The experimental group was supplemented with 50 g Dunaliella powder to give phytoene/phytofluene at a level of 1 g/kg diet, and the placebo was provided with the oxidized algae free of carotenoids at the same amount. Weight gain and tissues weight of rats fed on the control diet, or on the experimental diets were statistically same. Tissue analyses were carried out by liquid chromatography at the end of two weeks feeding for vitamin A, carotenoids, phytoene and phytofluene and theirs stereoisomers. Liver analyses revealed high hepatic storage of phytoene in the experimental group. Analysis of the other tissues, adrenal, brain, heart, kidney, lung, and spleen detected small amounts of phytoene in the adrenal, kidney and spleen and in the plasma. High-pressure liquid chromatography for stereoisomeric composition was performed to all phytoene-containing tissues. The original algal diet content of 9-cis-to-all-trans ratio of 1:1 was maintained in the plasma and adrenal while in the liver, spleen and kidney the ratio was reduced to 1:3. The preferential accumulation of all-trans phytoene over 9-cis phytoene in the liver, spleen and kidney may be interpreted as indicating stronger antioxidative effect of 9-cis phytoene over the all-trans isomer or alternatively, in vivo streoisomerization of 9-cis phytoene to the all-trans structure.     

Effect of sex and gonadal hormones on rat plasma lipids during the development of an essential fatty acid deficiency

1. Male, female and castrated rats treated with oestradiol (30mug./week) or testosterone (2mg./week) were given an essential fatty acid-deficient diet containing 10% of hydrogenated coconut oil for 9 weeks. The concentrations and fatty acid composition of plasma phospholipids, cholesteryl esters and triglycerides were determined. 2. Between the second and third weeks of the deficiency, concentrations of plasma cholesteryl esters, phospholipids and triglycerides decreased, then remained relatively constant. There were no significant differences between males and females, but oestradiol caused a significant rise in plasma phospholipids and triglycerides as compared with testosterone-treated animals. 3. During the first 2 weeks of the deficiency, linoleic acid in the plasma lipids of all groups decreased to low concentrations and changed very little thereafter. 4. Female rats maintained higher percentages and concentrations of arachidonic acid and stearic acid in plasma phospholipids and arachidonic acid in cholesteryl esters than did males. Males had higher proportions of eicosatrienoic acid and oleic acid. There was no sex difference in the fatty acid composition of plasma triglycerides. 5. Oestradiol-treated rats had concentrations of cholesteryl and phospholipid arachidonate comparable with those of female rats and higher than the testosterone-treated group. Eicosatrienoic acid in the oestradiol-treated rats was high and resembled that of the male rats, apparently because of the higher concentration of plasma phospho lipids in this group. 6. Supplementation of the essential fatty acid-deficient rats with linoleate restored plasma cholesteryl and phospholipid linoleate and arachidonate nearly to normal concentrations in a single day. The increase in arachidonic acid in these fractions was accompanied by a similar quantitative decrease in eicosatrienoic acid. 7. These sex differences appear to be related to the smaller size of the female rat and to a more direct influence of oestradiol on the formation or maintenance of phospholipids rich in arachidonic acid.     

Effect of age on the modification of rat plasma lipids by fish and soybean oil diets

The effects of sardine and soybean oils on plasma lipids have been studied in young and aged rats. Plasma cholesterol and bile acids of aged rats fed on a sardine oil diet decreased to a greater degree than those of young rats. Cholesterol, bile acids and phospholipids of the soybean oil diet group decreased only in aged rats. Increases in plasma eicosapentaenoic (sardine) and linoleic (soybean) acid levels of aged rats were observed to be greater than those of young rats. These results indicate that the age enhances the effects of fish and soybean oils on plasma lipids by suppressing their characteristic fatty acid metabolism.     

Methionine feeding prevents kidney stone deposition by restoration of free radical mediated changes in experimental rat urolithiasis

Feeding calculi producing diet (CPD) to rats for 4 weeks produced calcium oxalate stones deposition. Supplementation of methionine to CPD (m-CPD) prevented the stone deposition. However the urine pH and excretion of oxalate and calcium in m-CPD-fed rats was still as high as in CPD-fed groups compared to that of the control group. The CPD-fed rats exhibited an increase in liver oxalate synthesizing enzymes and glycolic acid oxidase (GAO) and lactate dehydrogenase (LDH), and these activities were not restored in m-CPD-fed rats. Similarly, the elevated LDH activity and oxalate concentration observed in the kidney of CPD-fed rats were not restored by methionine supplementation. Kidney sub-cellular fractions of CPD-fed rats showed increased susceptibility for lipid peroxidation in presence of iron, ascorbate, and t-butyl hydroperoxide. Antioxidant enzyme activities of superoxide dismutase (SOD), catalase, and glutathione peroxidase and antioxidant concentrations of reduced glutathione, total thiols, ascorbic acid, and vitamin E were significantly decreased, while the xanthine oxidase activity and concentrations of hydroxyl radical, diene conjugates, and hydroperoxides were significantly increased in CPD-fed rats. The susceptibility to lipid peroxidation, activities of antioxidant enzymes, and the concentration of antioxidants were normalized in m-CPD—fed rats, thus suggesting that methionine feeding prevents the stone formation by neutralizing the free radical induced changes.