The effects of large amounts of tryptophan, Pyrazinamide, or nicotinic acid in diets on the contents of total NAD (NAD+NADH) and NADP (NADP + NADPH) of various organs were investigated in mice with or without γ-irradiation. Female C3H/HeN mice were fed one of the following 4 kinds of experimental diets for one week: l) control diet (20% casein diet containing 3 mg niacin per 100 g diet); 2) diet supplemented by 0.5% L-tryptophan (T-diet); 3) diet supplemented by 0.5% L-tryptophan (T-diet); 3) diet supplemented by 0.5% pyrazinamide and 0.5% L-tryptophan (PT-diet); 4) diet supplemented by 0.1% nicotinic acid (NA-diet). Half of the mice in each group were subsequently irradiated with 8 Gy of y-ray (60Co) after 4 h of fasting. Then, the contents of total NAD and NADP in thymus, spleen, kidney, liver, and blood were determined in all animals. The results indicated that NAD content of spleen was higher in PT-group (21.5%) and NA-group (23.2%) than in that of control group. In thymus, however, NAD content of only the PT-group was significantly greater (13.1%) than control. NAD level of kidney was also significatly higher (32.6%) in PT-group. By γ-irradiation, NAD contents of thymus and spleen of all groups tended to be decreased, but those of kidney and liver were not always reduced. In the latter two organs, significant NAD reduction was shown only in kidney of PT-group and in liver of PT and NA-groups. Even after irradiation, NAD levels of spleen and thymus in PT and NA-groups tended to be kept higher than those in irradiated control group. On the other hand, NADP contents of all kinds of organs examined were not significantly affected by those dietary supplements. By the γ-irradiation, however, NADP levels of spleen and thymus were decreased remarkably in all dietary groups. NAD and NADP contents of blood were not significantly affected by those dietary supplements, and their levels were not altered by γ-irradiation except that NAD levels of T and NA-groups were slightly increased. These results indicate that ingestion of pyrazinamide-tryptophan or nicotinic acid influences the contents of pyridine nucleotides in some tissues and that such alteration affects the radiation-induced NAD(P) reduction in those tissues, a reduction which is possibly caused mainly by poly(ADP-ribose) synthesis reaction.
The transfer of menaquinone-4 (vitamin K2(20)) to the fetus and milk was studied in pregnant and lactating rats, respectively, after oral administration (4 mg/kg) of [3'-14C]menaquinone-4. Intestinal absorption of menaquinone-4 was rapid and the highest level of radioactivity in each tissue except guts of fetal rats was observed at 4 h after dosing. The level in the fetal homogenate was low. At that time, the concentration of menaquinone-4 in the fetal liver was 84 ng/g, corresponding to 9% of the value found in the placenta. Therefore, we conclude that the transfer of menaquinone-4 to the developing rat fetus is restricted by the blood-placenta barrier, but that a sufficient amount of menaquinone-4 (more than the essential amount of vitamin K to ensure full carboxylation) can be transferred into the fetal liver. It was also observed that the radioactivity was transferred to milk after oral administration to lactating rats. Milk/blood concentration ratios at 6 and 24 h after dosing were 13.8 and 65.1, respectively. The elimination half-life of radioactivity in milk was about 17 h. Eighty-four percent of milk radioactivity was due to menaquinone-4. These results suggest that the prophylactic maternal oral administration of menaquinone-4 may be efficacious for a prophylaxis of neonatal and infantile vitamin K deficiency.
To determine whether vitamin E protects against thyroxineinduced oxidative stress in heart and soleus (slow oxidative) muscles, lipid peroxide (thiobarbituric acid-reactive substances) and antioxidant enzymes were measured in those tissues of hyperthyroid rats supplemented with vitamin E. The rats were rendered hyperthyroid by the administration of L-thyroxme in their drinking water. In experiment (EXPT) 1, 30 mg/kg/dose of alpha-tocopheryl acetate was administered to the vitamin E-treated group. In EXPT II, the rats were fed a diet containing either <1 IU/kg (deficient diet), 20IU/kg (control E diet), or 500IU/kg (high E diet) of vitamin E and hyperthyroidism was induced. In EXPT I, hyperthyroidism induced an increase in oxidative enzymes, mitochondrial superoxide dismutase and lipid peroxide level, and a decrease in cytosolic superoxide dismutase, glutathione peroxidase and catalase in both tissues. Vitamin E treatment inhibited the increase in lipid peroxide level totally in the heart and partially in the soleus, with minimal changes in the other biochemical indices studied. In EXPT II, the lipid peroxide level was markedly increased in both tissues of the vitamin E-deficient group, and decreased in those of the group fed high E diet. There were some adaptive changes in the levels of cytosolic superoxide dismutase, glutathione peroxidase, and catalase in response to vitamin E deficiency, whereas neither oxidative enzymes nor mitochondrial superoxide dismutase were altered. These results suggest that vitamin E protects against lipid peroxidation in hyperthyroid heart and skeletal muscle independently of the changes in oxidative enzymes and antioxidant enzymes.
This study has been done to determine the effect of vitamin E deficiency on the functions of splenic lymphocytes and alveolar macrophages (AM) in rats. Vitamin E deficiency did not cause any changes of body weight, spleen and thymus weights, and numbers of splenocytes and AM compared with those of control rats. And also, we could not find any significant changes of lymphocyte responses to mitogens (PHA, Con A, and LPS) and natural killer cell (NK) activity except for AM function in vitamin E-deficient rats. In vitamin E-deficient rats, AM showed a higher phagocytosis than that of control rats. After in vitro treatment with a macrophage-activating factor (MAF) for 4 h at 37°C, AM from control rats showed a greater enhancement (167%) of phagocytic activity compared with that of AM from vitamin E-deficient rats. When the effect of MAF prepared from splenic lymphocytes of rats from control or vitamin E-deficient rats on phagocytosis of AM was studied, MAF from control rats showed an about 150% increase of phagocytic activity in a 1/250 dilution of MAF. However, MAF from vitamin E-deficient group had almost no effect on phagocytosis of AM in the same dilution of MAF as control rats. These results may suggest that vitamin E deficiency induces the higher phagocytic function of AM responsible for host defense in the lung, but their enhancement is not due to the activation by MAF from lymphocytes.
Effects of dietary ethanol on ascorbic acid and lipid metabolism, and liver drug-metabolizing enzymes in rats fed a semi-purified diet containing a powdered ethanol preparation (30 cal% in the diet) were studied. Administration of ethanol increased urinary ascorbic acid excretion (p<0.001) and ascorbic acid level in the liver (p<0.001) and the spleen (p<0.01). The activity of hepatic aniline hydroxylase was increased (p<0.05) by ethanol feeding but that of aminopyrine Ndemethylase was not. Increases of serum total and high-density-lipoprotein (HDL) cholesterol level, commonly observed by the administration of xenobiotics, were not observed. These results showed ethanol possessed rather similar properties to xenobiotics such as polychlorinated biphenyls (PCB) or 1, 1, 1-trichloro-2, 2-bis(p-chlorophenyl)ethane (DDT) in some metabolic changes. In this study, no accumulation of lipid in the liver was observed. Key Fords ethanol, ascorbic acid, drug-metabolizing enzymes, cholesterol, liver lipids
1. A lactose tolerance test was perfomed in infants and children. The majority of the infants showed a good response with serum glucose elevations, while there were poor responders among children more than 2 years old. During this test, serum galactose usually was nondetectable, even in the good responders. 2. After simultaneous loading with a constant amount of galactose and varying amounts of glucose in neonates, the degree of elevation of serum galactose levels decreased with increasing amounts of glucose, and loading with equal amounts of galactose and glucose resulted in no elevation of serum galactose levels. 3. In a 6-year-old galactosemic child, serum galactose levels were markedly and continuously elevated after lactose loading. 4. After galactose loading with simultaneous intravenous glucose loading in neonates, elevation of serum galactose was markedly suppressed, as compared with that after galactose loading alone, while it was higher than that after oral loading with the equal doses of galactose and glucose. From the above, the fact that no increase was observed in serum galactose concentration when lactose was loaded orally in neonates is ascribable partially to inhibited absorption of galactose by glucose in the intestine but in the most part to accelerated metabolism of galactose by the glucose absorbed.
The effect of 6-azauracil on j3-alanine metabolism was investigated in vivo in the rat. Both of the enzymes β-alanine-oxoglutarate aminotransferase (aminobutyrate aminotransferase) and D-3-aminoisobutyrate-pyruvate aminotransferase ((R)-3-amino-2-methylpropionate-pyruvate aminotransferase), which are β-alanine catabolizing enzymes from rat liver and kidney, were inactivated by 6-azauracil injection, while dihydrouracil dehydrogenase, dihydropyrimidinase, and J3-ureidopropionase, which are pyrimidine metabolizing enzymes, were not affected. The content of β-alanine was increased, but the level of uridine and uracil in rat liver was not affected, by 6-azauracil. When a crude enzyme preparation was passed through a Sephacryl S-200 column, both enzymes could be separated from each other. β-Aaanine-oxoglutarate aminotransferase and β-alanine-pyruvate aminotransferase activities in rat liver decreased to 27.4% and 63.9%, respectively, upon 6-azauracil injection, and those in kidney were 11.7% and 38.3%, respectively. From these findings, it is suggested that the accumulation of β-alanine in 6-azauracil-treated rat liver might be caused by the inhibition of β-alanine catabolizing enzymes, but not by an increase in the uridine pool nor by the activation of pyrimidine metabolism.
Rats hyper-resposive to a diet containing cholesterol plus cholic acid (exgenous hypercholesterolemic (ExHC) rats) were used to assess if cholesterol feeding at weanling period influences later serum cholesterol homeostasis. Diets containing cholesterol plus cholic acid (atherogenic diet) in early life, when compared to non-atherogenic diet, caused a transient suppression of serum cholesterol elevation in very-low and low-density lipoprotein fractions during refeeding of the atherogenic diet in later life. Such an effect was not observed when ExHC rats were early given a diet supplemented with cholesterol or cholic acid alone, nor when ordinary Sprague-Dawley rats were given atherogenic diet. Early atherogenic diet caused an increased secretion of cholesterol as very-low-density lipoprotein from the perfused livers of adult ExHC rats. Neither the activity of hepatic cholesterol-7α-hydroxylase of fecal steroid excretion in later life was influenced by the early dietary manipulation. Therefore, the present results show the deferred effect of early dietary manipulation on later serum cholesterol metabolism in ExHC rats, but the underlying mechanism(s) remains to be determined.
A high-performance liquid chromatographic procedure for the determination of carnitine that is converted to coenzyme A(CoA) stoichiometrically by carnitine acetyltransferase is described. The chromatographic separation was accomplished by using Unisil QC8 column and a mixture of 190 m t KH2PO4 and methanol (87: 13, v/v) as eluent. The present method is rapid, sensitive, and can be used for the routine analysis of animal tissues and plasma.
Cholesterol-lowering activity of enzymatic hydrolysate of bagasse alkaline extract was studied in rats fed a cholesterol-enriched diet. The bagasse alkaline extract was found to be vulnerable to the enzymic attack of a-amylase. Thus the alkaline extract was degraded into two fractions: long-chain fraction (polysaccharides) and short-chain fraction (oligosaccharides). The long-chain fraction was active in lowering the serum cholesterol level while feeding the short-chain fraction resulted in a slightly elevated serum cholesterol level. The feeding by gavege of the long-chain fraction 12 h after the meal also was effective in lowering serum cholesterol concentration. These findings were compatible with the concept that the bagasse alkaline extract affect the cholesterol dynamics apart from input-output balance of cholesterol. Possible mechanisms responsible for the cholesterol-lowering activity of the extract were discussed.
This study was conducted to determine the effect of a high protein diet on calcium metabolism in rat. Wistar strain male rats (50 days old) were divided into 5 groups (day 0): control diet (18% casein); high protein diet (18% casein +20% lactalbumin); high protein and 0.1% sodium bicarbonate diet; high protein and 0.2% sodium bicarbonate diet; and high protein and 0.4% sodium bicarbonate diet. On days 0, 1, 3, 5, 7, 9, urine samples were collected and, at the same time, feces were collected from half of the animals in each group. Urinary titratable acidity (TA-HCO3-), ammonium ion (NH4+), and net acid excretion (NAE) were measured as an index of acid-base balance in rat body. Urinary volume was rapidly increased and the increase of urinary volume continued throughout the study in rats fed the high protein diet. Urinary excretions of calcium and phosphorus were increased after day 3 and day 1, respectively, in rats fed the high protein diet. The high protein diet depressed calcium absorption and elevated phosphorus absorption from the digestive tract in rats fed the high protein diet. The high protein diet decreased TA-HCO3-, which was closely correlated with the decrease of NAE. Sodium bicarbonate supplementation to the high protein diet had little effect on urinary calcium excretion and NAE. This study suggested that there was no relationship between metabolic acidosis and hypercalciuria in rats fed the high protein diet.
Six variable supplementations of thiamine magnesium, and sulfates were given to 30 male adult rats in their diets. After 3 weeks, the concentrations of thiamine in the blood and liver and those of cholesterol, phospholipids, and triglycerides in the serum were determined. Blood thiamine level did not reflect the vitamin content in liver. Sufficient and/or excessive intake of the 3 supplementations caused an increase in liver thiamine content and body weight gain; it also caused a reduction in serum cholesterol level without a change in the levels of serum triglycerides and phospholipids. Deficiency of both magnesium and sufate salts in thiamine-supplemented groups decreased body weight gain and liver thiamine content with a significant elevation of serum triglycerides.
The nutritive utilization of calcium was studied in adult rats in which 50% of the distal small intestine (DSI) had been resected and in sham-operated controls one month and three months after the operation. Resection of half the DSI reduced the digestive utilization of Ca as reflected by mineral content in bone. Three months after resection, nutritive utilization of Ca had still not recovered. Feeding the resected rats with a diet in which fat content consisted of equal parts of medium-chain triglycerides (MCT), sunflower seed oil, and olive oil failed to improve nutritive utilization of Ca after one or three months in comparison with a diet containing olive oil as the only source of lipids. Supplementation with vitamin D3 (0.04 mg/100 g diet) enhanced nutritive utilization of Ca in resected rats after one month, the beneficial effect becoming much more patent after three months. At the dose used, vitamin D3 favored calcium deposition in bone tissue. Serum levels of Ca remained unchanged under all experimental conditions, both one month and three months after 50% DSI resection.
Protein binding properties of 22-oxa-lα, 25-dihydroxyvitamin D3(22-oxa-1, 25-D3), a synthetic analogue of 1α, 25-dihydroxyvitamin D3(1, 25-D3), were compared with those of vitamin D3derivatives. The order of binding affinity to the chick embryonic intestinal receptor was 1, 25-D3>22-oxa-1, 25-D3>25-hydroxyvitamin D3(25-D3) >24R, 25-dihydroxyvitamin D3(24, 25-D3) >vitamin D3(D3), while that to the rat plasma vitamin D-binding protein (DBP) was 25-D3>24, 25-D3>D3>1, 25-D3>22-oxa-1, 25-D3. The binding potencies of 22-oxa-1, 25-D3to the receptor and DBP were about 1/8 and 1/600 of the respective values of 1, 25-D3. When the distribution of the tritiated compounds in human plasma components was examined by an in vitro polyacrylamide gel electrophoretic method, [3H]-22-oxa-1, 25-D3was found to bind only to the lipoproteins including chyromicron. These results suggest that the replacement of a carbon atom into an oxygen atom in the side chain structure of 1, 25-D3results significant decrease in the binding affinity to DBP and that 22-oxa-1, 25-D3is transported as a complex-form not with DBP but with lipoprotein to the target tissues.