The effects of vitamin E on toxicity by minute amounts of paraquat fed continuously for some period to rats were investigated. Two experiments were carried out as experiments 1 and 2. In both experiments, weaning rats were divided at first into two groups; one group was given a vitamin E-deficient diet, and the other a vitamin E-supplemented control diet (50mg α-tocopherol/kg of diet). They were fed on these diets for 40 days. After that, in both experiments, the rats that had been fed the vitamin E-deficient diet were further divided into two groups, which were either given a paraquat-added diet (+PQ-E) or continuously fed the same vitamin E-deficient diet (-E). The amount of paraquat added was 250 mg of methyl viologen per kg of diet. After the addition of paraquat, these two groups were pair-fed. In experiment 1, paraquat was given to all the rats fed the vitamin E-supplemented control diet (+PQ+E). In experiment 2, rats fed the control diet were divided into paraquat-added (+PQ+E) and non-paraquat-added (+ E) groups, similar to those of vitamin E-deficient rats. These two groups were also pair-fed thereafter. In both experiments, about 35 days after paraquat addition, they were sacrificed. Plasma and liver α-tocopherol contents were measured by HPLC, and liver peroxidation value was measured by chemiluminescence and the TBA method. And, as parameters of vitamin E deficiency, plasma pyruvate kinase and GOT activities and a-cysteine proteinase inhibitor (α-CPI) level were measured. When the analyzed values were compared between paraquat-added and the corresponding not-added control groups (+PQ-E vs. -E, +PQ+E vs. +E), the following results were obtained. In experiment 1, the values of plasma and liver α-tocopherol levels were significantly lower in the +PQ-E group than those of the -E group; however, liver peroxidation values and values of the three parameters of vitamin E deficiency were not different significantly. In experiment 2, the value of liver α-tocopherol level was significantly lower in the +PQ+E group than that of the +E group. As to liver peroxidation values, in the case of TBA reactive substance (TBA-RS), the value of the +PQ-E group was significantly higher than that of the -E group, and in the case of chemiluminescence, the value of the +PQ+E group was significantly higher than that of the +E group. As to the three parameters of vitamin E deficiency, the values of all three parameters were significantly higher in the +PQ-E group than those of the -E group, and the values of pyruvate kinase activity and α-CPI level were significantly higher in the +PQ+E group than those of the +E group. But, when ratios of weights of lung, kidney and liver to body weight were compared, these values increased significantly in both experiments by paraquat addition irrespective of the presence of vitamin E. Moreover, in experiment 2, occurrence of gross pathological signs were noticed in the paraquat-fed two groups.

View full abstract

The contents of total, free, and bound vitamin B₂ (B₂) in bovine milk and their distribution in four separate milk fractions, including milk during the early lactation stage, were estimated. The total B₂ content in whole mature milk was 179±25μg/100g (n=16), and its distribution in the cream, whey, skim milk membrane, and casein fractions was 6, 67, 9, and 18%, respectively. The amount of flavins bound to protein in the total B₂ was 13.6% in whole milk and rich in membrane fraction. The total B₂ content (μg/100g of milk) was higher in colostrum at 1-3 days (287±120) than in colostrum at 4-7 days (173±27), in transitional milk (182±33), and in mature milk (179±44). The bound flavin content decreased slightly as lactation progressed (20-30μg/100g), but the ratio of bound/total B2 did not vary (12-15%). Milk fat globule membrane (MFGM) contained 414±65μg of B₂/g of protein, most of it being bound to protein (92%). Market milks contained as much total B₂ as raw whole milk, but the amount of bound form was only 2%. Guanidine HCl, urea, sodium dodecyl sulfate, pH at 3.0-3.5, delipidation, and boiling released most of the B₂ bound to protein, suggesting that bound flavins bind to milk proteins by a hydrophobic linkage.

View full abstract

The effects of dietary zinc (Zn) and cadmium (Cd) on tissue selenium (Se) concentration and glutathione peroxidase (GSH-Px) activity were studied in weanling male Wistar rats. One group of rats was fed a purified diet based on casein and sucrose, and the other rats used in a 2×2×2 factorial arrangement of treatment were fed this diet supplemented with 0.1mg Se/kg, either as DL-selenomethionine or sodium selenite and plus 100mg Zn/kg as zinc sulfate or 5mg Cd/kg as cadmium chloride or both for 4 weeks. Se concentrations in plasma, erythrocytes, muscle, heart, and liver were significantly elevated by Zn. Cd significantly decreased Se concentration in muscle. Addition of Zn to the diets markedly increased (p<0.001) hepatic GSH-Px activity. However, Cd in the diets produced a significant increase (p<0.001) in erythrocyte GSH-Px activity. These results indicate that Zn level of marginal deficiency(8.6mg/kg diet) can decrease Se availability and a small excess of Zn increases Se availability for hepatic GSH-Px activity.

View full abstract

The effects of dietary protein and soybean oil on the metabolism of L-tryptophan through the NAD pathway and the activity of α-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD) [EC 4.1.1.45] in rat liver and kidney were investigated. The animals were fed on the following niacin-free diets for 11 days: group 1, a fat-free 20% casein diet (20% Cas); group 2, a fat-free 40% casein diet (40% Cas); group 3, a 40% casein diet containing 20% soybean oil (40% Cas+20% F). After feeding on each diet for 7 days, the urine was collected during 48 h. On day 9, L-tryptophan was force-fed and the urine was collected during 48h. Niacin metabolites such as N-methylnicotinamide (MNA), N-methyl-2-pyridone-5-carboxamide (2-Py) and N-methyl-4-pyridone-3carboxamide (4-Py) in the urine samples were analyzed by chromatography. The activity of ACMSD in the liver and kidney was assayed immediately after the last urine collection. The results indicate that the urinary excretion of the niacin metabolites in the 40% Cas group was lower than that of the 20% Cas group in spite of the more intake of tryptophan in the former group. On the other hand, in the 40% Cas+20% F group, tryptophan intake was lower and the excretion of the metabolites was significantly higher than that in the 40% Cas group. The hepatic ACMSD activity in the 40% Cas group was 5.8 times that of the 20% Cas group and that in the 40% Cas+20% F group was one tenth that of the 20% Cas group. These results indicate that the ratio of the excreted metabolites to the tryptophan intake was reduced by the high dietary protein level, but increased by the addition of high soybean oil. The data analysis shows that the amount of urinary total niacin metabolites ([TNM]: MNA+2-Py+4-Py) could be expressed in the following equation in the rats fed on each diet: where [ACMSD] is the hepatic ACMSD activity, [Trp] the tryptophan intake, and Δw the body weight gain.

View full abstract

The effect of milk and skim milk intake on serum lipid and apoprotein levels was investigated in young females with consideration of each subject's menstrual period. When milk and dairy products were not allowed, the serum cholesterol concentration tended to decrease in high density lipoprotein (HDL) and very low density lipoprotein (VLDL), the triglyceride concentration tended to increase in HDL and low density lipoprotein (LDL), the phospholipid concentration showed no change, and the apoB, apoC-III and apoE significantly decreased. In the milk group, VLDL cholesterol and phospholipid concentrations were increased with a significant increase in the apoB concentration after intake of 200ml/day of milk for one menstrual period, and these levels did not change when the milk intake was doubled. VLDL phospholipid increased and apoE decreased after the intake of 20g/day of skim milk, and LDL cholesterol and HDL phospholipid concentrations tended to decrease when the skim milk intake was doubled.

View full abstract

The effect of ascorbic acid deficiency on serum levels of high density lipoprotein- (HDL-), low density lipoprotein- (LDL-), very low density lipoprotein- (VLDL-) and chylomicron-cholesterol was examined in ODS-od/od rat (ODS rat), that is a rat mutant unable to synthesize ascorbic acid. Male ODS rats were fed an ascrobic acid-free diet for 20 days. In another two groups, the diet supplemented with 300mg ascorbic acid/kg diet was fed either ad libitum (ad libitum control) or in pair-feeding (pair-fed control). Pair-fed rats received the same amount of diet as rats fed the ascorbic acid-free diet. Serum level of total cholesterol in the ad libitum control rats, ascorbic acid-deficient rats, and the pair-fed control rats were 100.1±8.4mg/dl, 92.8±6.2mg/dl and 72.2±4.8mg/dl, respectively. The level of LDL-cholesterol in ascorbic acid-deficient rats was significantly higher than that in the ad libitum control or that in the pair-fed control. The level of HDL-cholesterol in ascorbic acid-deficient rats was lower than that in the ad libitum control, but was not changed as compared with that in the pair-fed control. Ascorbic acid deficiency did not affect serum level of VLDL-cholesterol or chylomicron-cholesterol as compared with those in the controls. These results demonstrate that ascorbic acid deficiency causes the elevation of serum level of LDL-cholesterol both in ad libitum feeding condition and pair feeding condition.

View full abstract

The effects of dietary pantethine levels on the contents and compositions of fatty acids and on the levels of lipid peroxides were investigated with rat liver and its S-9 fraction under administration of 0 (non), 0.2 (low dose), and 0.35ml (high dose) of autoxidized linoleate (AL) per 100g body weight of the rats per day for 5 days. AL having 800meq/kg of peroxide value (PV) and 1, 700meq/kg of carbonyl value (CV) was dosed to the rats of each group given drinking water containing 0mg% (deficient), 6.25mg% (adequate), and 125mg% pantethine (excess). In the pantethine-deficient and -adequate groups, the contents of fatty acids both in the liver homogenate and in the S-9 fraction were correspondingly decreased by increasing dose levels of AL, and the decrease was remarkable especially in the pantethine-deficient group, but was not significant in the pantethine-excess group even by a high dose of AL. Particularly, in the high dose of AL, the notable decreases of oleic acid (C_18:1) contents in both the liver and the S-9 fraction were observed in rats of the pantethine-deficient and -adequate groups. The thiobarbituric acid (TBA) values in the liver homogenate and the S-9 fraction were increased correspondingly by increasing dose levels of AL, and the increases were repressed in the pantethine-excess group.

View full abstract

Effect of vitamin B₂ deficiency on rat liver dihydropyrimidine dehydrogenase was investigated. It was found that the purified enzyme contains 2 mol flavin per molecule, which consists of equal proportions of flavinTadenine dinucleotide (FAD) and riboflavin 5'-phosphate (FMN). When rats were fed on a vitamin B₂-deficient diet for 5 weeks, dihydropyrimidine dehydrogenase activity in the liver was diminished, followed by a decrease in enzyme concentration. Moreover, the addition of exogenous FAD or FMN did not restore the activity. Thus endogenous flavin may regulate the enzyme half-life or synthesis. Lowering of dihydropyrimidine dehydrogenase activity in the livers of rats fed on a vitamin B₂-deficient diet did not affect the uridine, uracil and ∑UMP (the sum of acid soluble uracil 5'-nucleotides) pool in liver.

View full abstract

Four-week-old Wistar male rats were fed a vitamin E (VE)-deficient (OE) or a VE-sufficient (10E) diet for 6 weeks and then intraperitoneally treated with buthionine sulfoximine (BSO) at 1mmol/kg body weight once a day for 3 days. Glutathione (GSH) depletion by BSO treatment caused injuries especially in the kidneys of VE-deficient rats. The kidney weight increased in the VE-deficient rats after BSO treatment (OE-BSO). It was observed that the epithelial cells of the renal tubules in this group were strongly impaired and the injuries were necrosis and desquamation. No injury was observed in the kidneys of the BSO-untreated 0E group and the 10E groups. The TBA value of the kidney of 0E-BSO group was lower than that of the BSO-untreated OE group, but the lipofuscin content of the kidney of the OE-BSO group was 10 times higher than that of the BSO-untreated 0E group. These results suggest that the kidney injuries in rats may be caused by lipid peroxidation induced by vitamin E deficiency and glutathione depletion.

View full abstract

Effects of corn fiber residue (5g/day for 10 days) on fecal weight, moisture, pH, fecal flora, ammonia content, and on the activities of β-glucuronidase and β-glucosidase were investigated in six healthy subjects. Corn fiber residue was remnant of hemicellulose extraction from corn fiber by calcium hydroxide. Fecal weight showed a tendency to increase, and fecal pH did not change during corn fiber residue supplementation. No remarkable changes in the fecal flora at the bacterial group level were observed. Fecal ammonia content and β-glucuronidase activity per gram of wet feces decreased slightly but the daily output did not change. Fecal β-glucosidase activities per gram of wet feces increased significantly (p<0.05) and the daily output also tended to increase during corn fiber residue supplementation.

View full abstract