Effects of Dietary Level of Iron and Ascorbic Acid on Cadmium Toxicity in Rats

The transxylosylation reaction products of β-xylosidase-1, excreted by Penicillium wortmanni IFO 7237 using β-(1→4)-xylobiose as substrate, have been separated by chromatography on activated charcoal into four fractions, designated as P-1, P-2, P-3, and P-4, respectively. They were further purified by preparative paper chromatography. The characterization and structural analysis were done by measurement of the degree of polymerization (DP) and specific rotation followed by methylation analysis. Moreover, the enzymatic structural analysis of transxylosylation products, with high performance liquid chromatography (HPLC), allowed the confirmation of each structure. The first product, P-1, was β-(1→3)-xylobiose and the second, P-2, was β-(1→4)-xylotriose, but, P-3 was O-β-d-xylopyranosyl-(1→3)-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose or isomeric xylo-triose and P-4 was assumed to be O-β-d-xylopyranosyl-(1→4)-[O-β-d-xylopyranosyl-(1→3)]-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose.     

Effect of Dietary Composition on Lipids in Serum and in Liver of Rats Fed a Cystine-excess Diet

The effects of dietary composition on lipids in serum and in liver of rats fed with a cystine- excess diet were investigated.

When starch was used as the carbohydrate source, the addition of excess-cystine caused an increase in serum cholesterol and phospholipids, and hepatomegaly. Phospholipids in serum of rats fed with a cystine-excess diet containing 5% corn oil were higher than those with a cystine-excess diet that was low in corn oil (0.1 %). The addition of konjac mannan and pectin prevented hypercholesterolemia, and the rise in phospholipids in serum was prevented by the addition of konjac mannan.

Liver cholesterol (mg/liver/100 g of body wt.) increased in rats fed with a cystine-excess diet.

The addition of excess cystine to a diet containing sucrose as the carbohydrate source resulted in a marked increase of cholesterol in serum and liver, and a decrease of serum triglycerides.

The replacement of starch by sucrose in the cystine-excess diet increased liver cholesterol.

Lipids, cholesterol, phospholipids and triglycerides in the liver, but not phospholipids, when expressed as mg per g of liver for rats fed with the diets containing sucrose, increased when compared to those for rats fed with the diets containing starch. In contrast, serum triglycerides increased.     

Effect on Lipids in Liver and Serum,and Some Urinary Components of Dietary Supplement of Excess Lysine Given to Previously Starved or Non-starved Rats

In order to obtain further information on the changes in liver lipids, either a basal or a lysine-sexcess diet was refed to previously starved rats or fed to previously non-starved rats. Liver lipid accumulation was observed in previously starved rats refed the lysine-excess diet for 7 days, but not in rats without previous starvation. The liver lipid did not accumulate with another 8 days’ feeding (15 days⁹ refeeding). The addition of methionine alone or in combination with threonine to the lysine-excess diet had no effect on the liver lipid level. The decrease in serum triacylglycerol in rats refed the lysine-excess diet was preceded by lipid accumulation in the liver. Urinary potassium during the initial two days increased with refeeding and feeding. Marked excretion of orotate was observed for 2 days from the initiation of refeeding of the lysine-excess diet and it then decreased. Thus, such a marked increase in the urinary excretion of orotate might be associated with the stimulation of orotate biosynthesis and with lipid accumulation in the liver.     

Short-term Effects of Ethanol Intoxication on Ascorbic Acid and Lipid Metabolism and on Drug-metabolizing Enzymes in Liver of Rats

The effects of one-time ethanol intoxication on ascorbic acid and lipid metabolism and on drug-metabolizing enzymes in liver of rats were investigated. Male Donryu rats that had been fed semi-purified feed were given 5 g/kg ethanol solution (25%, w/v) via a stomach tube and killed 16 h after intubation. The amount of ascorbic acid excreted in the urine after ethanol administration increased, but renal and adrenal concentrations of ascorbic acid decreased. The serum levels of total cholesterol, high-density-lipoprotein cholesterol, triglycerides, phospholipids, and non-esterified fatty acids were elevated in rats given ethanol, but hepatic level of total lipids, cholesterol, triglycerides, phospholipids were not. The hepatic concentrations of cytochrome P-450 and cytochrome b₅ did not increase, but this large dose of ethanol increased the activities of aminopyrine N-demethylase and cytochrome c reductase.

These results indicated that the single dose of ethanol affected the ascorbic acid and lipid metabolism of rats, and induced drug-metabolizing enzymes in their liver.     

Effects of Dietary Polychlorinated Biphenyls and Protein Level on Liver and Serum Lipid Metabolism of Rats

The effects of polychlorinated biphenyls (PCB) and dietary protein level on the liver and serum lipid metabolism of rats were studied. Rats were fed an experimental diet containing 7 or 30% casein with or without 0.1 % PCB for 24 days. Dietary PCB increased the level of triglyceride, phospholipid and cholesterol in the liver. The accumulation of triglyceride and cholesterol in liver was markedly increased with a low protein diet. The incorporation of injected ³H₂O into liver cholesterol was increased by PCB, but not affected by the dietary level of protein. The incorporation of the tracer into liver fatty acids was not increased by PCB intake. Dietary PCB also raised serum cholesterol and phospholipid, while PCB decreased triglyceride level, especially in rats on low protein diet. In addition, PCB intake clearly raised serum high density lipoprotein and diminished very low density lipoprotein. In the low protein group, PCB markedly repressed the incorporation of ³H₂O into serum lipids. The results suggest that the hepatic lipids accumulation by the addition of 0.1 % PCB to a low protein diet might be mainly ascribed to a repression in the transport of triglyceride from liver to blood. KEY WORDS: PCB, dietary protein, liver lipids, serum lipoprotein.     

Influence of Amino Acid Supplementation to Egg Albumin Reacted with Oxidized Lipids on Liver Lipids of Rats

Fatty infiltration in the liver of rats fed a low egg albumin diet was apparently disappeared by substituting the protein source for the albumin reacted with oxidized lipids (the mixture of egg albumin-ethyl linoleate (2: 1, w/w) was kept at RH 80.4% and at 50°C for 7 days and defatted). The present study deals with the mechanism causing such a phenomenon.

The decrease in the content of liver triglyceride (TG) due to feeding the reacted albumin was essentially disturbed by supplementing amino acids for lost ones accompanied by lipid oxidation.

Feeding the amino acid mixture simulating the reacted albumin showed the same response to the reacted protein.

Supplementation of basic amino acids damaged to the amino acid mixture simulating the reacted albumin increased the content of liver TG, while that of sulfur amino acids inclined to decrease liver TG.

These results indicate that the disappearance of fatty liver in rats fed the reacted albumin is almost entirely, but not exclusively, ascribed to the change in the amino acid pattern, particulary to the loss of the basic amino acids. However, since the plasma lipid levels did not respond similarly, participation of other factor(s) could not be excluded.     

Effects of Dietary Nasunin on the Serum Cholesterol Level in Rats

The effects of nasunin, a major anthocyanin in eggplant, and its aglycone, delphinidin, on the serum cholesterol conpentration were determined in rats fed with a cholesterol-enriched diet. The serum total cholesterol and HDL-cholesterol concentrations tended to be decreased and increased, respectively, by feeding nasunin and delphinidin, while the fecal excretion of both cholesterol and bile acids tended to be increased by feeding with the anthocyanins. There was no difference between the nasunin and delphinidin activity to decrease serum total cholesterol, nor to increase serum HDL-cholesterol or the fecal excretion of cholesterol and bile acids. These results suggest that the slightly lower serum total cholesterol concentration in rats fed with nasunin and delphinidin may in part be due to inhibition of the intestinal absorption of both cholesterol and bile acids by these anthocyanins, and that the delphinidin moiety of nasunin mainly contributes to this activity.     

Effects of Ethanol and Polychlorinated Biphenyls in Combination on Ascorbic Acid Metabolism,Liver Drug-metabolizing Enzymes,and Lipid Metabolism in Rats

We investigated the combined effects of ethanol and polychlorinated biphenyls (PCB) on ascorbic acid metabolism, liver drug-metabolizing enzymes, and lipid metabolism in rats fed on a diet containing by 36% by energy of ethanol and 0.005% of PCB, either singly or in combination, for 49 days. Ethanol and PCB given together synergistically affected the amount of ascorbic acid excreted in the urine and the serum concentration of ascorbic acid. This synergistic effect was also observed in the activity of aniline hydroxylase in the liver. Ethanol and PCB given together seem to have had different effects on lipid metabolism. These results suggest that the effect of ethanol on the metabolism of ascorbic acid and of drugs may be enhanced by combined administration with PCB, and that the ascrobic acid deficiency and/or modification of the drug metabolism may become more serious.     

Serum and Urinary Folate in Liver Disease

During the active phase of viral hepatitis urinary folate loss was found to be 8·0 to 48·3 (mean 31·1) μg./day, compared with a normal urinary folate excretion of 0·1 to 18·0 (mean 9·5) μg./day. In cirrhosis and cardiac failure with congestive hepatomegaly the corresponding values were 25·8 to 55·0 (mean 35·7) μg./day and 2·5 to 61·6 (mean 26·9) μg./day, respectively. Urinary folate loss may be a significant factor in the aetiology of folate deficiency of chronic liver disease, particularly when dietary intake is poor.After prolonged dialysis in Visking casing urinary folate was almost totally dialysable, but an appreciable fraction of serum folate was not, even after 72 hours. The dialysable (free) folate fraction of serum and urine disappeared maximally during the first six hours'' dialysis, and was virtually cleared after 24 hours'' dialysis; clearance curves in normal individuals and in liver disease were comparable. The non-dialysable serum folate fraction was of similar magnitude in all subjects studied, in spite of marked variation in total folate, and probably represented protein-bound folate.     

Effects of Ellagic Acid on Copper,Zinc, and Biochemical Values in Serum and Liver of Experimental Cholestatic Rats

Ellagic acid (EA) is a natural polyphenolic compound. Although, modulator effects of EA on copper (Cu) and zinc (Zn) levels in some liver diseases have been reported in experimental animals, its effects in obstructive jaundice (OJ) has not been clarified. We aimed to evaluate potential effects of EA on Cu and Zn levels in liver and serum of cholestatic rats. Forty Wistar albino rats were equally divided into four groups. First group was used as controls. Second group received EA (60 mg⁻¹ kg⁻¹ day⁻¹) for 8 days. Third was OJ group, and fourth group was OJ plus EA group. After 8 days, blood and liver samples were obtained. Higher serum and liver Cu and lower serum and liver Zn levels were found in OJ group (p < 0.05) compared with other groups. However, these differences reached to significant levels for Cu in serum and for Zn in lever. Higher serum copper levels were decreased, and lower liver Zn levels were increased by EA treatment in cholestatic rats (p < 0.05). Also, higher Cu/Zn ratio in OJ group was decreased by EA treatment both in liver (p < 0.05) and in serum (p < 0.05). Significantly higher serum bilirubin, alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase values were found in OJ and OJ + EA groups compared with the control and EA groups (p < 0.05). In conclusion, result of the current study indicated that ellagic acid has modulator effects on Cu and Zn levels in liver and serum of cholestatic rats.     

Defatting and Desalting Treatment of Indonesian Dried-salted Fish: Dietary Effects on Alpha-tocopherol and Peroxide Levels in the Serum and Liver of Rats

The main problem with dried-salted fish (DSF) products is lipid oxidation. PUFA of fish oil is very easily oxidized, and sodium chloride is known to be a pro-oxidant. Many researchers have found that the products of lipid oxidation had negative effects on a variety of species, so we evaluated the effect of a desalting and defatting treatment on the lipid oxidation of Indonesian DSF. The dietary effect of untreated DSF, defatted DSF and desalted DSF on diarrhea, on the internal organs, on hepatic, serum, and urinary lipid peroxidation, and on hepatic and serum alpha-tocopherol were evaluated by using rats. The defatting treatment had a significant effect (p < 0.01) on reducing the lipid oxidation variables of the DSF sample and on protecting the rats from diarrhea. Compared with the rats in the casein group, these in the untreated DSF group had significantly higher values (p < 0.05) for hepatic, serum and urinary lipid peroxidation, but significantly lower values for hepatic and serum alpha-tocopherol. No significant differences were observed between the rats fed with casein and defatted DSF.     

共轭亚油酸甘油酯对大鼠血清脂肪酸组成影响的研究

目的：研究共轭亚油酸甘油酯对高脂饮食大鼠血清脂肪酸组成变化的影响;方法：60 只SD 大鼠随机分为5 组：正常对照 组、高脂对照组,共轭亚油酸甘油酯低（2 g/kg·bw）、中（4 g/kg·bw）、高（6 g/kg·bw）剂量组,除基础对照组外其余各组均喂饲高脂 饲料,建立高脂模型,以灌胃方式给予受试物,6 周后取血清测定其脂肪酸组成。采用一步法直接对血清中脂肪酸进行甲酯化,气 相色谱毛细管柱分离,氢火焰离子化检测器（FID）定性定量分析;结果：共轭亚油酸甘油酯低、中、高剂量组大鼠血清中单不饱和 脂肪酸含量为25.66%,18.74%,17.72%,与高脂对照组相比显著性下降（P<0.01）,各剂量组饱和脂肪酸和多不饱和脂肪酸含量分 别为48.08%,48.52%,51.15%和27.03%,29.28%,31.13%,与高脂对照组相比显著性升高（P<0.01）。几种代表性脂肪酸如各剂量 组中的油酸、亚油酸与高脂对照组相比分别增加了26.48%,41.56%,51.26% 和9.18%,8.61%,8.73%,各剂量组中棕榈酸与高脂对 照组相比降低了5.28%, 8.80%, 10.92%。结论：共轭亚油酸甘油酯能够增加大鼠血清中饱和脂肪酸和多不饱和脂肪酸的含量,减 少单不饱和脂肪酸含量,改变血清脂肪酸组成。     

Effects of Dietary Fish Oil on Polyunsaturated Fatty Acid Desaturation in Fetal and Postnatal Rats

The effects were determined of dietary fish oil on the polyunsaturated fatty acid desaturation in rats fed on fish oil-containing diets (FS group) and on non-fish oil diets (CN group) during the fetal to postnatal periods. Although the desaturase activity in the liver microsomes of the FS group was higher than that of the CN group before birth, this was not altered by dietary fish oil after birth. However, a lower 20:4n-6 concentration before and after birth, and lower linoleic acid desaturation index ((dihomo-γ-linolenic acid + arachidonic acid)/linoleic acid)) at 10 wk of age in the FS group than in the CN group were observed in the liver microsomal phospholipids. The Δ6-desaturase activity in the brain microsomes of the FS group was lower than that of the CN group. These findings suggest that an intake of dietary fish oil by dams and postnatal rats affected the arachidonic acid concentration due to the decreased desaturase activity in the rats’ microsomes.     

Gastroprotective and Anti-oxidative Properties of Ascorbic Acid on Indomethacin-induced Gastric Injuries in Rats

Reactive oxygen species (ROS) have been implicated in the etiology of indomethacin-induced gastric mucosal damage. This study investigated ascorbic acid (vitamin C)'s protective effects against oxidative gastric mucosal damage induced by indomethacin. Ascorbic acid is a powerful antioxidant because it can donate a hydrogen atom and form a relatively stable ascorbyl free radical. We have investigated alterations in the levels of myeloperoxidase, antioxidant system enzymes (glutathione S-transferase, superoxide dismutase, glutathione reductase, catalase, glutathione peroxidase), lipid peroxidation and glutathione, as markers for ulceration process following oral administration of ascorbic acid, famotidine, lansoprazole, and ranitidine in rats with indomethacin-induced ulcers. In the present study, we found that (1) ascorbic acid, famotidine, lansoprazole and ranitidine reduced the development of indomethacin-induced gastric damages; (2) the administration of indomethacin caused a significant decrease in the levels of superoxide dismutase, glutathione peroxidase, glutathione S-transferase and glutathione, and an increase in the lipid peroxidation level; (3) the administration of ascorbic acid reversed the trend, inducing a significant increase of these enzymes' levels and a reduction in lipid peroxidation level in tissues; and (4) catalase, glutathione reductase and myeloperoxidase activities, increased by indomethacin, were found to be lower in the ascorbic acid, famotidine, lansoprazole and ranitidine-treated groups. The results indicate that the gastroprotective properties of ascorbic acid could be related to its positive effects on the antioxidant system and myeloperoxidase activity in indomethacin-induced gastric ulcers in rats.     

几种天然产物对高尿酸血症大鼠血清尿酸水平的影响初探

目的:探讨几种天然产物对高尿酸血症大鼠血清尿酸水平及尿酸排泄的影响.方法:对wistar大鼠灌胃氧嗪酸钾和酵母膏,制作高尿酸血症大鼠动物模型.灌胃给药褐藻糖胶、柠檬酸钾和东哥阿里提取物,2周后采血并进行代谢实验,检测血清尿酸、尿素氮,24小时尿液体积、pH值、尿酸浓度及总量,分析三种活性物质对机体尿酸水平、尿酸排泄、肾脏功能的影响.结果:三种物质均可显著降低高尿酸血症模型大鼠的血清尿酸水平,其中东哥阿里提取物组的24小时排泄尿酸总量较模型组显著降低,褐藻糖胶对实验大鼠的血清尿素氮水平升高有抑制作用.结论:三种活性物质对高尿酸血症大鼠血清尿酸浓度有降低作用,其中褐藻糖胶对肾脏功能有保护作用,从而保证尿酸的顺利排泄,而东哥阿里在降低血尿酸水平的同时,24小时尿液中排泄的尿酸总量也显著低于模型对照组,其机制可能与抑制尿酸生成有关.     

昆布（海带）对高脂血症大鼠血脂的调节作用和机制

目的：探讨昆布（海带）在实验性高脂血症大鼠中的降血脂作用和机制。方法：健康雌性Wistar大鼠40只,应用高脂饲料喂养方法建立高脂血症动物模型,海带粉饲料喂养干预治疗。生化法检测大鼠血清甘油三酯（TG）、总胆固醇（TC）、低密度脂蛋白（LDL）和高密度脂蛋白（HDL）水平。硫代巴比妥酸法和硝酸还原酶法分别检测脂质过氧化物丙二醛（MDA）和一氧化氮（NO）含量,黄嘌呤氧化酶法和化学比色法分别测定超氧化物歧化酶（SOD）和谷胱甘肽过氧化物酶（GSH-PX）活性。结果：经海带干预治疗后,动物血清TG、TC和LDL水平较模型组显著降低、HDL水平显著升高（P〈0.05）。治疗组动物血清和肝组织MDA和NO水平显著低于、而SOD和GSH-PX活性均显著高于模型组（P〈0.05）。结论：海带可能影响TG、TC、LDL和HDL等组分的代谢,通过增强抗氧化SOD和GSH-PX的活性,降低体内MDA和NO的水平,发挥调节血脂水平的作用。     

Effects of Iron Overload on Ascorbic Acid Metabolism

Studies of the ascorbic acid status in two subjects with idiopathic haemochromatosis and in 12 with transfusional siderosis showed that all had decreased levels of white cell ascorbic acid. The urinary excretion of ascorbic acid was also diminished in those subjects in whom such measurements were made. The administration of ascorbic acid was followed by only a small rise in the urinary ascorbic acid output, while the oxalic acid levels (measured in two subjects) showed a significant rise. These findings resemble those described in siderotic Bantu, and support the thesis that increased iron stores lead to irreversible oxidation of some of the available ascorbic acid.