Increase in heart glutathione redox ratio and total antioxidant capacity and decrease in lipid peroxidation after vitamin e dietary supplementation in guinea pigs

Dietary treatment with three diets differing in vitamin E, Low E (15 mg of vitamin E/kg diet), Medium E (150 mg/kg), or High E (1,500 mg/kg), resulted in guinea pigs with low (but nondeficient), intermediate, or high heart a-tocopherol concentration. Neither the antioxidant enzymes superoxide dismutase, catalase, glutathione peroxidase, and reductase, nor the nonenzymatic antioxidants, GSH, ascorbate, and uric acid were homeostatically depressed by increases in heart a-tocopherol. Protection from both enzymatic (NADPH dependent) and nonenzymatic (ascorbate-Fe²⁺) lipid peroxidation was strongly increased by vitamin E supplementation from Low to Medium E Whereas no additional gain was obtained from the Medium E to the High E group. The GSH/GSSG and GSH/total glutathione ratios increased as a function of the vitamin E dietary concentration closely resembling the shape of the dependence of heart a-tocopherol on dietary vitamin E. The results show the capacity of dietary vitamin E to increase the global antioxidant capacity of the heart and to improve the heart redox status in both the lipid and water-soluble compartments. This capacity occurred at levels six times higher than the minimum daily requirement of vitamin E, even in the presence of optimum dietary vitamin C concentrations and basal unstressed conditions. The need for vitamin E dietary supplementation seems specially important in this tissue due to the low constitutive levels of endogenous enzymatic and nonenzymatic antioxidants present of the mammalian heart in comparison with those of other internal organs.     

Vitamin E Concentrations in the Brains and Some Selected Peripheral Tissues of Selenium-Deficient and Vitamin E-Deficient Mice

Abstract: Weanling male CD-1 mice were fed control, vitamin E-deficient or selenium-deficient diets for periods of 12 to 20 weeks. α-Tocopherol concentrations in plasma, liver, and testes, as well as in three specific areas in the brain (cerebral hemisphere, cerebellum, and medulla plus pons) were determined by high performance liquid chromatography. Significant concentrations of α-tocopherol were found in all brain samples from vitamin E-deficient animals long after the peripheral tissues were depleted, indicating that brain is more resistant to vitamin E deficiency than peripheral tissues. Cerebellar concentrations of α-tocopherol were consistently lower than those of cerebral hemisphere and medulla-pons. Further more, the cerebellar α-tocopherol concentration sustained a larger decline than the other two brain areas within 6 weeks of vitamin E deficiency treatment. These and other data suggest that cerebellum may be more susceptible to damage from vitamin E deficiency than other parts of the brain. Selenium deficiency did not affect brain a-tocopherol concentrations during the 12 weeks of the study.     

Concentrations of vitamin A, beta-carotene and vitamin E in individual bovine follicles of different quality

The degree of atresia of the follicle had no influence on the intrafollicular concentrations of beta-carotene, vitamin E and cholesterol. This might result from the passive transfer of these substances from blood to follicular fluid bound to high density lipoproteins. However, concentrations of vitamin A in follicular fluid were significantly (P less than 0.001) influenced by follicle quality, with highest concentrations (0.32 microgram/ml) in non-atretic follicles and lowest values (0.15 microgram/ml) in greatly atretic follicles. The higher concentrations of vitamin A in healthy follicles might be due to a local conversion of beta-carotene into vitamin A in follicular structures. By influencing hormone and protein synthesis, vitamin A may have a potential for local modulation of follicular development and therefore be one of the factors controlling recruitment, selection and growth of the dominant follicle in cattle.     

Photoprotective potential of lycopene,beta-carotene,vitamin E,vitamin C and carnosic acid in UVA-irradiated human skin fibroblasts

The photoprotective potential of the dietary antioxidants vitamin C, vitamin E, lycopene, beta-carotene, and the rosemary polyphenol, carnosic acid, was tested in human dermal fibroblasts exposed to ultraviolet-A (UVA) light. The carotenoids were prepared in special nanoparticle formulations together with vitamin C and/or vitamin E. Nanoparticle formulations, in contrast to dimethylsulphoxide, stablized lycopene in the cell culture medium and allowed efficient cellular uptake. The presence of vitamin E in the formulation further increased the stability and cellular uptake of lycopene. UVA irradiation of the human skin fibroblasts led to a 10-15-fold rise in metalloproteinase 1 (MMP-1) mRNA. This rise was suppressed in the presence of low microM concentrations of vitamin E, vitamin C, or carnosic acid but not with beta-carotene or lycopene. Indeed, in the presence of 0.5-1.0 microM beta-carotene or lycopene, the UVA-induced MMP-1 mRNA was further increased by 1.5-2-fold. This increase was totally suppressed when vitamin E was included in the nanoparticle formulation. Heme-oxygenase 1 (HO-1) mRNA expression was strongly induced by UVA irradiation but none of the antioxidants inhibited this effect at the concentrations used in this study. Indeed, beta-carotene or lycopene (0.5-1.0 microM) led to a further 1.5-fold rise in the UVA-induced HO-1 mRNA levels. In conclusion, vitamin C, vitamin E, and carnosic acid showed photoprotective potential. Lycopene and beta-carotene did not protect on their own but in the presence of vitamin E, their stability in culture was improved and the rise in MMP-1 mRNA expression was suppressed, suggesting a requirement for antioxidant protection of the carotenoids against formation of oxidative derivatives that can influence the cellular and molecular responses.     

Effects of vitamin C and vitamin E on lipid peroxidation, blood serum metabolites, and mineral concentrations of laying hens reared at high ambient temperature

This study was conducted to determine the effects of vitamin C (L-ascorbic acid) and vitamin E (alpha-tocopherol acetate) on serum concentrations of lipid peroxidation (MDA) and triiodothyronine (T3), thyroxine (T4), adrenocorticotropic hormone (ACTH), and some metabolite and mineral in laying hens reared at high ambient temperatures ranging from 25 degrees C to 35 degrees C. One hundred twenty laying hens (18 wk old; Hy-Line) were divided into 4 groups, 30 hens per group. The laying hens were fed either a basal diet (control) or the basal diet supplemented with either 250 mg of L-ascorbic acid/kg of diet (vitamin C), 250 mg of alpha-tocopherol acetate/kg of diet (vitamin E), or 250 mg of L-ascorbic acid plus 250 mg alpha-tocopherol acetate/kg of diet (combination). Separately or as a combination vitamins C and E increased serum vitamin C and vitamin E concentrations (p < 0.001) but decreased serum MDA concentration (p < 0.05). Serum concentrations of vitamin E and vitamin C were found highest but serum MDA concentration was lowest in the combination group. Supplemental vitamins C and E either separately or in a combination increased serum T3 and T4 concentrations (p < 0.05), whereas decreased serum ACTH concentration (p < 0.01). Serum glucose and cholesterol concentrations decreased, whereas serum protein concentration increased (p < 0.05) when vitamins C and E singly or together were added to the diet. Vitamin C and vitamin E supplementation resulted in an increase in serum concentrations of Ca, P, and K (p < 0.01) but a decrease in serum concentration of Na (p < 0.05). The results of the present study suggest that supplemental vitamin C and vitamin E alter serum lipid peroxidation, vitamin C, vitamin E and metabolite status, and diets supplemented with a combination of these two vitamins offer a good management practice in laying hens reared at high temperatures. In addition, the results suggest that dietary vitamin C and vitamin E act synergistically.     

Transport of vitamin E by differentiated Caco-2 cells

In hepatocytes, vitamin E is secreted via the efflux pathway and is believed to associate with apolipoprotein B (apoB)-lipoproteins extracellularly. The molecular mechanisms involved in the uptake, intracellular trafficking, and secretion of dietary vitamin E by the intestinal cells are unknown. We observed that low concentrations of Tween-40 were better for the solubilization and delivery of vitamin E to differentiated Caco-2 cells, whereas high concentrations of Tween-40 and sera inhibited this uptake. Vitamin E uptake was initially rapid and then reached saturation. Subcellular localization revealed that vitamin E primarily accumulated in microsomal membranes. Oleic acid (OA) treatment, which induces chylomicron assembly and secretion, decreased microsomal membrane-bound vitamin E in a time-dependent manner. To study secretion, differentiated Caco-2 cells were pulse-labeled with vitamin E and chased in the presence and absence of OA. In the absence of OA, vitamin E was associated with intestinal high density lipoprotein (I-HDL), whereas OA-treated cells secreted vitamin E with I-HDL and chylomicrons. No extracellular transfer of vitamin E between these lipoproteins was observed. Glyburide, an antagonist of ABCA1, partially inhibited its secretion with I-HDL, whereas plasma HDL increased vitamin E efflux. An antagonist of microsomal triglyceride transfer protein, brefeldin A, and monensin specifically inhibited vitamin E secretion with chylomicrons. These studies indicate that vitamin E taken up by Caco-2 cells is stored in the microsomal membranes and secreted with chylomicrons and I-HDL. Transport via I-HDL might contribute to vitamin E absorption in patients with abetalipoproteinemia receiving large oral doses of the vitamin.     

Influence of vitamin E and C supplementation on lipoprotein oxidation in patients with Alzheimer's disease.

Because increased oxidation is an important feature of Alzheimer's disease (AD) and low concentrations of antioxidant vitamins C and E have been observed in cerebrospinal fluid (CSF) of AD patients, supplementation with these antioxidants might delay the development of AD. Major targets for oxidation in brain are lipids and lipoproteins. We studied whether supplementation with antioxidative vitamins E and C can increase their concentrations not only in plasma but also in CSF, and as a consequence decrease the susceptibility of lipoproteins to in vitro oxidation. Two groups, each consisting of 10 patients with AD, were for 1 month supplemented daily with either a combination of 400 IU vitamin E and 1000 mg vitamin C, or 400 IU vitamin E alone. We found that supplementation with vitamin E and C significantly increased the concentrations of both vitamins in plasma and CSF. Importantly, the abnormally low concentrations of vitamin C were returned to normal level following treatment. As a consequence, susceptibility of CSF and plasma lipoproteins to in vitro oxidation was significantly decreased. In contrast, the supplementation with vitamin E alone significantly increased its CSF and plasma concentrations, but was unable to decrease the lipoprotein oxidizability. These findings document a superiority of a combined vitamin E + C supplementation over a vitamin E supplementation alone in AD and provide a biochemical basis for its use.     

Effects of intraperitoneally administered lipoic acid,vitamin E,and linalool on the level of total lipid and fatty acids in guinea pig brain with oxidative stress induced by H2O2

The aim of our study was to investigate the protective effects of intraperitoneally-administrated vitamin E, dlalpha lipoic acid, and linalool on the level of total lipid and fatty acid in guinea pig brains with oxidative stress that was induced by H2O2. The total brain lipid content in the H2O2 group decreased when compared to the H2O2 + vitamin E (p<0.05), H2O2+ linalool (p<0.05), ALA (p<0.05), control (p<0.01), linalool (p<0.01), and vitamin E (p<0.01) groups. While the proportion of total saturated fatty acid ( infinity SFA) in the H2O2 group significantly increased (p<0.005) when compared to the vitamin E group, it only slightly increased (p<0.01) when compared to the control and H2O2 + vitamin E groups. The ratio of the total unsaturated fatty acid (infinity USFA) in the H2O2 groups was lower (p<0.05) than the control, vitamin E, and H2O2+ vitamin E groups. The level of the total polyunsaturated fatty acid (infinity USFA) in the H2O2 group decreased in when compared to the control, vitamin E, and H2O2+vitamin E groups. While the proportion of the total w3 (omega 3), w6 (omega 6), and PUFA were found to be lowest in the H2O2 group, they were slightly increased (p<0.05) in the lipoic acid group when compared to the control and H2O2 + lipoic acid groups. However, the level of infinity SFA in the H2O2 group was highest; the level of infinity USFA in same group was lowest. As the proportion of infinity USFA and infinity PUFA were found to be highest in the linalool group, they were decreased in the H2O2 group when compared to the control group. Our results show that linalool has antioxidant properties, much the same as vitamin E and lipoic acid, to prevent lipid peroxidation. Additionally, vitamin E, lipoic acid, and linalool could lead to therapeutic approaches for limiting damage from oxidation reaction in unsaturated fatty acids, as well as for complementing existing therapy for the treatment of complications of oxidative damage.     

Photoprotective potential of lycopene, β-carotene, vitamin E, vitamin C and carnosic acid in UVA-irradiated human skin fibroblasts

The photoprotective potential of the dietary antioxidants vitamin C, vitamin E, lycopene, β-carotene, and the rosemary polyphenol, carnosic acid, was tested in human dermal fibroblasts exposed to ultraviolet-A (UVA) light. The carotenoids were prepared in special nanoparticle formulations together with vitamin C and/or vitamin E. Nanoparticle formulations, in contrast to dimethylsulphoxide, stablized lycopene in the cell culture medium and allowed efficient cellular uptake. The presence of vitamin E in the formulation further increased the stability and cellular uptake of lycopene. UVA irradiation of the human skin fibroblasts led to a 10–15-fold rise in metalloproteinase 1 (MMP-1) mRNA. This rise was suppressed in the presence of low μM concentrations of vitamin E, vitamin C, or carnosic acid but not with β-carotene or lycopene. Indeed, in the presence of 0.5–1.0 μM β-carotene or lycopene, the UVA-induced MMP-1 mRNA was further increased by 1.5–2-fold. This increase was totally suppressed when vitamin E was included in the nanoparticle formulation. Heme-oxygenase 1 (HO-1) mRNA expression was strongly induced by UVA irradiation but none of the antioxidants inhibited this effect at the concentrations used in this study. Indeed, β-carotene or lycopene (0.5–1.0 μM) led to a further 1.5-fold rise in the UVA-induced HO-1 mRNA levels. In conclusion, vitamin C, vitamin E, and carnosic acid showed photoprotective potential. Lycopene and β-carotene did not protect on their own but in the presence of vitamin E, their stability in culture was improved and the rise in MMP-1 mRNA expression was suppressed, suggesting a requirement for antioxidant protection of the carotenoids against formation of oxidative derivatives that can influence the cellular and molecular responses.     

Dolichol in Human Brain: Regional and Developmental Aspects

Distinct regional differences in dolichol content were defined in human brain from 15 to 76 years of age. Concerning the regional distribution of dolichol, levels were: higher in cortical gray matter than in subcortical white matter, highest among cortical regions in temporal gray matter, highest among all brain regions in thalamus, and lowest among all brain regions in lower brain stem and spinal cord. The developmental changes in the contents of dolichol were found to be different among brain regions. For example, among regions with the highest levels of dolichol, in thalamus there was a six to sevenfold increase, but in parietal gray matter, only a 2.5-fold increase. Regional and developmental changes in the proportions of the individual molecular species (isoprenologues) of dolichol were also observed. The findings indicate that the metabolism of dolichol is not uniform among regions of developing and aging human brain and may have implications for the role of dolichol in normal and diseased human brain.     

Antiproliferative effects of tocopherols (vitamin E) on murine glioma C6 cells: homologue-specific control of PKC/ERK and cyclin signaling

Chemoprevention strategies for brain tumors (specifically gliomas) are few and surprisingly poorly investigated. We have studied the effects of tocopherols (TOCs; vitamin E) on proliferation and death processes of murine glioma C6 cells. These vitamers showed different cell uptake and concentration- and time-dependent inhibitory effects on cell growth that were significant at the lowest concentrations tested (1-10 microM). However, the inhibitory potency of TOCs seemed to reflect at least in part their actual cell concentrations at steady state, with the order of magnitude gamma-TOC >or= alpha-TOC > delta-TOC approximately or = beta-TOC. Moreover, for extracellular concentrations >or=10 microM, TOCs also showed a significant cytotoxic effects due mainly to necrosis, while apoptosis was negligible. Gamma-TOC (the form showing preferential cell uptake and lowest unspecific cytotoxicity) was the most effective inhibitor of cell cycle progression (arrest in G0/G1 phase) leading to lowered expression of cyclin E and cyclin-dependent kinases 2 and 4 and overexpression of p27 (specific inhibitor of S-phase entering). According to these signals, activated ERK1/2 and PKC upstream and Rb phosphorylation downstream were decreased. In conclusion, within TOCs the gamma form exerts the most potent and specific control of cell cycle progression in C6 cells (cytostatic effect). This suggests a chemopreventive role of this form of vitamin E in gliomas.     

Phosphatidylcholine metabolism in isolated rat heart: modulation by ethanol and vitamin E

Prolonged ethanol administration has been reported to cause defects in cardiac performance and abnormal cardiac lipid contents. However, little is known regarding the short-term administration of ethanol to the perfused heart and its effect on cardiac phospholipid metabolism. In this study, the isolated Langendorff heart perfusion was used as a model to study the effects of ethanol and a combination of ethanol and vitamin E (DL-alpha-tocopherol) on phospholipid metabolism. When perfused with 1% ethanol for 4 h, the major cardiac phospholipids were not altered but a 60% increase in lysophosphatidylcholine level was observed. Studies on the lysophosphatidylcholine metabolic enzymes revealed that phospholipase A (both phospholipase A1 and A2) activity was enhanced in the ethanol-perfused heart, but lysophospholipase and acyltransferase activities were unaffected by ethanol treatment. When the heart was perfused with 1% ethanol in the presence of 50-100 microM vitamin E, the ethanol-induced lysophosphatidylcholine accumulation was completely abolished. This was largely attributed to the attenuation of phospholipase A activities by vitamin E. In order to delineate the opposing effects of ethanol and vitamin E on phospholipid metabolism in the heart, phospholipase A activities in the subcellular fractions were determined in the presence of 0.5-2.0% ethanol or a combination of 1% ethanol and 0-100 microM vitamin E. Ethanol alone exhibited a biphasic effect on phospholipase A activity with maximum stimulation of enzyme activities at 1% concentration. When phospholipase A was assayed in 1% ethanol and vitamin E (25-100 microM), its activity was inhibited by vitamin E in a dose-dependent manner. The mechanism by which ethanol enhanced phospholipase A activities was further investigated with a partially purified enzyme from the rat heart cytosol. Kinetic studies with different concentrations of phosphatidylcholine revealed that at low substrate concentrations, ethanol was inhibitory to the reaction, whereas at high substrate concentrations, the reaction was enhanced by ethanol. Vitamin E (50 microM) completely abolished the ethanol-induced enhancement of enzyme activity in a noncompetitive manner. Since lysophosphatidylcholine is cytolytic at high concentration and its accumulation in the heart has been postulated as a biochemical cause of cardiac dysfunction, the level of the lysolipid in the heart must be under rigid control. Our result suggest that the modulation of cardiac phospholipase A activity is an important mechanism for the the regulation of lysophosphatidylcholine levels in the rat heart.     

Biochemical interaction of arachidonic acid and vitamin e in human platelets

The effect of α-tocopherol on the oxidative transformation of arachidonic acid was investigated in human platelets. The major products of lipoxygenase and cyclo-oxygenase pathways were separated by high performance liquid chromatography (HPLC) and thin layer chromatoggaphy (TLC) evaluated by scanning the radiochromatograms. This study differs from others in the vitamin E field in important aspects of its experimental design: the prelabeling of platelets with non-aggregating concentrations of ¹⁴C-arachidonic acid, and the addition of α-tocopherol as a colloidal suspension rather than as an ethanolic solution. A moderately potent but consistent reduction of apparent cyclo-oxygenase activity by α-tocopherol could be demonstrated by TLC and HPLC. This effect was best shown by the change of the HETE/HHT ratio which increased significantly in vitamin E-treated platelets. It was found to be dosedependent up to 1 MM a-tocopherol, the maximal concentration tested in this study. Alpha-tocopherol quinone was equally effective in this action.     

Regional and Subcellular Distribution of Thy-1 in Human Brain Assayed by a Solid-Phase Radioimmunoassay

A solid-phase radioimmunoassay, specific for the monomeric form of human Thy-1, was developed and used for quantitation of the Thy-1 antigen in human brain tissue. Determination of Thy-1 in homogenates of 12 anatomically defined brain regions showed that Thy-1 is present throughout the human brain. However, significant variation was found in the expression of the glycoprotein in different regions. Thy-1 appears to be generally enriched within gray matter: caudate nucleus, cerebral cortex, and putamen were found to contain the highest Thy-1 concentration (approximately 2.5 micrograms Thy-1/mg protein). Interestingly, the cerebellar cortex contained only 25% of the Thy-1 concentration of cerebral gray matter. Cerebral subcortical white matter contained half the amount of Thy-1 compared to cerebral cortex. Determination of Thy-1 in subcellular fractions prepared from human brain biopsy tissue indicated that the highest relative concentration of Thy-1 is associated with synaptosomal membranes and myelin/axonal membrane fractions.     

Absorption,Transport and Metabolism of Vitamin E

Vitamin E includes eight naturally occurring fat-soluble nutrients called tocopherols and dietary intake of vitamin E activity is essential in many species. α-Tocopherol has the highest biological activity and the highest molar concentration of lipid soluble antioxidant in man. Deficiency of vitamin E may cause neurological dysfunction, myopathies and diminished erythrocyte life span. α-Tocopherol is absorbed via the lymphatic pathway and transported in association with chylomicrons. In plasma α-tocopherol is found in all lipoprotein fractions, but mostly associated with apo B-containing lipoproteins in man. In rats approximately 50% of α-tocopherol is bound to high density lipoproteins (HDL). After intestinal absorption and transport with chylomicrons α-tocopherol is mostly transferred to parenchymal cells of the liver were most of the fat-soluble vitamin is stored. Little vitamin E is stored in the non-parenchymal cells (endothelial, stellate and Kupffer cells). α-Tocopherol is secreted in association with very low density lipoprotein (VLDL) from the liver. In the rat about 90% of total body mass of α-tocopherol is recovered in the liver, skeletal muscle and adipose tissue. Most α-tocopherol is located in the mitochondrial fractions and in the endoplasmic reticulum, whereas little is found in cytosol and peroxisomes. Clinical evidence from heavy drinkers and from experimental work in rats suggests that alcohol may increase oxidation of α-tocopherol, causing reduced tissue concentrations of α-tocopherol. Increased demand for vitamin E has also been observed in premature babies and patients with malabsorption, but there is little evidence that the well balanced diet of the healthy population would be improved by supplementation with vitamin E.     

Effect of vitamin on 2-deoxy-d-glucose uptake in human fibroblast cultures

Summary 2-Deoxy-d-glucose (2-DOG) uptake was tested in human fibroblast cultures in the presence and absence of vitamin E. Addition of 10 μg/ml vitamin E to the culture medium significantly reduced this uptake for 2-DOG concentrations of 0.005, to 10 mmol/liter (P≤0.01). The decrease of 2-DOG uptake was inversely proportional to the rise in 2-DOG concentration (P≤0.01). The presence of vitamin E reduced by 71% the average cellular level of lipid peroxides (expressed as thiobarbituric acid reactive substances) and caused a small but significant decrease in the cholesterol concentration (P≤0.01). These last results might explain the decrease in 2-DOG uptake observed in the presence of vitamin E.     

Serum Retinol,alpha‐tocopherol,and lipids in four species of adult captive pinnipeds

The sera of adult aquarium‐held pinnipeds from four species (family Phocidae: harbor seals (Phoca vitulina) and gray seals (Halichoerus grypus); family Otariidae: northern fur seals (Callorhinus ursinus) and California sea lions (Zalophus californianus)) were analyzed for vitamin A (retinol), vitamin E (α‐tocopherol), total cholesterol, triglycerides, phospholipids, and fatty acids. Each subject animal was healthy at the time of blood collection, was fasted for at least 12 hr prior to sampling, and was maintained on a constant diet and supplement regime throughout the study. Retinol values for the four species ranged from 0.16 to 0.92 μg/mL, with the lowest concentrations seen in the harbor seals and the highest in the northern fur seals. Vitamin E values ranged from 10.55 to 43.58 μg/mL, with northern fur seals showing the highest and gray seals the lowest levels. Vitamin E/lipid ratios (cholesterol, triglyceride, phospholipid, and total lipids) were also examined. A significant correlation was seen between vitamin E and total lipids (P<0.05) and phospholipid (P<0.01). Statistical analysis of the retinol, tocopherol, triglyceride, and phospholipid levels showed significant differences between phocid and otariid seals. Otariids had significantly lower tocopherol and phospholipid values (19.36 μg/mL, 4.29 mg/mL) and the phocids had significantly lower retinol and triglyceride levels (0.29 μg/mL, 124 mg/dL). There was no significant difference in serum cholesterol. Zoo Biol 22:83–96, 2003. © 2003 Wiley‐Liss, Inc.     

Assay and subcellular localization of the arylsulphatases in rat brain

—The properties and subcellular localization of type I (nitrophenyl) and type II (nitrocatechol) arylsulphatases were investigated in brain tissue of the rat, and optimal assay conditions were established. Sulphate, phosphate and sulphite ions inhibited the nitrocatechol sulphatases; nitrophenyl sulphatase was inhibited only by sulphite. The presence of latent enzyme activity was demonstrated for the nitrocatechol sulphatases, beta-glucuronidase, and beta-glycerophosphatase in rat and mouse brain homogenates. These hydrolases were highly sensitive to mechanical and osmotic damage; and Triton X-100 was very effective in releasing their latent (bound) activities, a finding suggestive of a lysosomal localization. Activity of nitrophenyl sulphatase was unaffected by osmotic changes or Triton X-100, characteristics suggesting a membranous association for this enzyme. Total activity of nitrophenyl sulphatase was approximately twice as great in canine gray matter as in canine white matter; the converse obtained for beta-glucuronidase activity. Values for total enzymic activity of the nitrocatechol sulphatases in canine white and gray matter were similar. Fractionation of homogenates from rat brain by differential centrifugations and separation of crude mitochondrial fractions by sucrose density gradient centrifugations revealed the following: (1) most of the nitrocatechol sulphatase activity (93 per cent) and all of the nitrophenyl sulphatase activity were sedimentable; (2) crude mitochondrial fractions exhibited the highest relative specific activity (RSA = 1·38) for the nitrocatechol sulphatases, whereas microsomal fractions displayed the highest RSA for nitrophenyl sulphatase (1·89); (3) the lightest fraction (A + B) and the densest fraction (E) from the sucrose density gradient contained most of the activity for both the type I and type II arylsulphatases, whereas the RSA of cytochrome oxidase was greatest in the intermediate density regions (fractions C and D); (4) the highest RSA for beta-glucuronidase and beta-glycerophosphatase occurred in gradient fraction C; (5) appreciable activity of beta-glycerophosphatase was found in a nerve ending fraction (M₃). It is suggested that the hydrolases in heterogeneous tissue like brain might be associated with lysosomal particles of differing enzyme compositions and varying populations, and that the data on distribution lend credence to the concept of bimodal and possible trimodal particle affinity for the hydrolases of brain tissues.     

Effect of dietary fish oil, vitamin E, and probucol on renal injury in the rat

Dietary fish oil, vitamin E, and probucol have been considered in a variety of human and experimental models of kidney disease. Using subtotal nephrectomized cholesterol-fed rats as a model for progressive kidney disease, we examined the effect of 5% dietary fish oil, or a combination of 5% dietary fish oil with 500 IU vitamin E/kg diet or 1% probucol on renal injury. Three-month-old Sprague Dawley rats were fed a control diet (C group) or a cholesterol supplemented (2%) diet (Ch group) containing either fish oil (FO group) or fish oil plus vitamin E (FO+E group) or fish oil plus probucol (FO+P group). After 4 weeks of dietary treatment, the right kidney was electrocoagulated and the left kidney nephrectomized. After 8 weeks, 24-hour urine was collected before sacrifice. No effect of the dietary treatments was noted on serum creatinine, blood urea nitrogen, or proteinuria, except that proteinuria was highest in FO+P group. Rats receiving the cholesterol diets had higher serum low density lipoprotein (LDL) + very low density lipoprotein (VLDL) cholesterol (P < 0.05). In contrast, rats in the FO+P group had the lowest serum total cholesterol and LDL+VLDL cholesterol among all groups. The FO group had 26% lower kidney alpha-tocopherol concentrations than the C group. However, inclusion of vitamin E in the diet (FO+E group) increased the kidney alpha-tocopherol status to a level comparable to that in the C group, whereas inclusion of probucol in fish oil diet (FO+P group) did not improve the kidney alpha-tocopherol status. Rats fed the cholesterol diet had a 2.5-fold higher glomerular segmental sclerosis (GSS) score and 1.5-fold higher glomerular macrophage (GM) subpopulation than the C group. These effects of the cholesterol diet were ameliorated by a fish oil diet (FO group: GSS by 30%, GM by 24%). The inclusion of vitamin E in the fish oil diet (FO+E group) did not further improve the GSS score or GM subpopulation. However, inclusion of probucol in fish oil diet (FO+P group) lowered the GSS score by 73% and reduced GM subpopulation by 83% compared with the Ch group. These remarkable changes can be attributed to the powerful hypocholesterolemic activity of probucol. Our findings indicate that progression of glomerular sclerosis in the rat remnant kidney model of progressive kidney disease can be significantly modulated with fish oil treatment.     

Effects of phosphorus and vitamin C deficiency,vitamin A toxicity,and lipid peroxidation on skeletal abnormalities in Atlantic halibut (Hippoglossus hippoglossus)

Dietary nutrients play an important role in skeletal tissue metabolism of fish. Deficiency and toxicity of certain nutrients have been linked to bone deformities in larval and juvenile fish. The pathogenesis of skeletal disorders in larval and juvenile fish from the same genetic stock, cultured under similar environment conditions is often difficult to distinguish when marginal deficiencies of multiple nutrients are involved. A study was conducted to characterize the skeletal deformities linked to the deficiency of phosphorus and ascorbic acid, vitamin A toxicity and lipid peroxidation in juvenile halibut. Five experimental diets containing a low level of phosphorus (0.5% dry matter basis), no vitamin C supplement, high level of vitamin A (80 000 IU kg^?1) and oxidized marine fish oil (peroxide value, 7.53 meq kg^?1) and a control diet based on cod fillet and vitamin free casein were fed to juvenile Atlantic halibut for 14 weeks in an attempt to characterize the skeletal deformities. Phosphorus, ascorbic acid, retinol, and α‐tocopherol concentrations of liver and kidney were measured at 0 and 14 weeks. Reduced vertebral ash and phosphorus content were observed in fish fed the low phosphorus diet. Skeletal abnormalities included abnormal hemal and neural spines in the hemal region and scoliosis in the cephalic and hemal regions of the vertebral column. Hepatic and kidney ascorbic acid concentrations were significantly lower in the group fed no ascorbic acid supplement. Skeletal abnormalities were scoliosis and lordosis primarily in the hemal region of the vertebral column. High levels of vitamin A in the diet caused increased hepatic retinol content and scoliosis spanning the cephalic/prehemal and anterior hemal regions of the vertebral column. Fish fed the oxidized oil diet showed increased thiobarbituric acid (TBA) value in the liver and muscle tissue with no significant decrease in hepatic vitamin E concentration. The most frequent skeletal deformity observed was scoliosis, spanning the cephalic/prehemal regions as well as the anterior hemal region of the vertebral column. The pattern and type of abnormalities observed in fish fed these experimental diets were similar to those observed in a commercial halibut hatchery.