Enzymatic activity of xenobiotic metabolism in rats with a varying body allowance of vitamin B1

Vitamin B1 in rats induced in the liver elevation of activity of metabolic enzymes of xenobiotics bound with membranes (dimethylaniline N-demethylase, aniline n-hydroxylase, aryl esterase). At the same time activity of the cytoplasmatic enzymes alcohol dehydrogenase and glutathione-S-transferase was appreciably lowered. An additional load with thiamine (20 mg/kg) led to a drop in activity of the membrane-bound enzymes. Vitamin B1 deficiency modified the effect of the inductor phenobarbital. Additional administration of vitamin B1 to thiamine-deficient animals normalized the thiamine level in the liver, and activity of hydroxylase, aryl esterase, formaldehyde dehydrogenase, and significantly decreased demethylase activity. In vitamin B1-deficient animals high detergent concentrations significantly suppressed NADH-dichlorophenol-indophenol-reductase activity, while low concentrations activated this enzyme as compared to the control.     

Features of thiamine metabolism with vitamin B1 deficiency in hypokinesis

The authors have studied activity of thiamine-dependent enzymes: transketolase, pyruvate- and alpha-ketoglutarate dehydrogenases, the content of thiamine diphosphate in the tissue of the liver and musculus gastrocnemius, activity of transketolase of the whole blood hemolysates and different age populations of red blood cells under 15-day hypokinesia with B1-deficiency induced by enteral administration of oxythiamine. The animals received oxythiamine in a dose of 2 mg/kg during 15 days. It was found that limitation of motor activity significantly aggravated the course of vitamin deficiency resulting in disordered utilization of coenzymic thiamine, and in a more pronounced suppression of vitamin-dependent enzymes (transketolase, alpha-ketoglutarate dehydrogenase) activity.     

Thiamine metabolism in experimental hepatitis and the intake of Naftusia mineral water

The level and metabolism of vitamin B1 and its coenzymic form were studied in the tissues and subcellular structures of the internal organs of white rats with experimental toxic hepatitis, receiving mineral water naphtusya. It was found that naphtusya given per os stimulated the metabolism of thiamine pyrophosphate (TPP), enhanced its concentration in the hepatic tissue and intestinal mucosa, producing a stabilizing effect on the TPP activity. It is concluded that the mineral water naphtusya can be used for enteral correction of vitamin balance in hepatitis patients.     

Specific activity of thiamine and oxythiamine immobilized on modified cellulose

The effect of thiamine and oxythiamine preparations on the activities of vitamin B1-dependent enzymes in the body of white mice was studied. It was found that the cellulose oxythiamine derivative was similar to the initial compound in the character and intensity of its antivitamin action. It was also shown that the cellulose thiamine derivative had a prolonged effect in the body, which was manifested in a slower increase in the activities of transketolase, pyruvate dehydrogenase and in the amount of thiamine diphosphate in tissues of vitamin B1-deficient animals, as compared to the effect of thiamine.     

Influence wheat bran on organism vitamin (experiment on rats)

The inclusion of wheat bran (at a dose of 2,3 and 4,6% of the dry weight) in the semi-synthetic diet of rats under combined deficiency of vitamins (20 and 50% of the adequate level) did not have a significant effect on vitamins C, B1 and B2 liver levels, riboflavin blood plasma level, and thiamine and riboflavin urinary excretion. The consumption of bran in high dose has been accompanied by a decrease of retinol blood plasma level on 19-28% but it has no effect on liver retinol palmitate content. Bran intake in both doses resulted in a deterioration of rats sufficiency with vitamin E, which had been confirmed by a simultaneous significant decrease of blood plasma alpha-tocopherol concentration on 31-40%, and its liver level on 23-43%. The results obtained indicate the advisability of vitamin E enrichment of diets with a high content of dietary fiber.     

The effect of various levels of chitosan in rat diet on vitamins assimilation under their combined deficiency

he effect of chitosan inclusion in the semi-synthetic diet of rats at a dose of 0,24 and 0,9% of dry weight on vitamin assimilation under combined moderate and deep deficiency has been studied. Four-week introduction of chitosan did not have a significant effect on levels of vitamins C, B1, B2 and A in the liver of animals, on vitamin B2 blood plasma concentration and thiamine and riboflavin urinary excretion regardless of the degree of vitamin deficiency intensity. The significantly decrease of vitamin E blood plasma concentration has been observed at high dose of chitosan in the diet under moderate vitamin deficiency, whereas under deep deficit such reduction has been detected even at a low dose. Thus, long-term chitosan inclusion in the diet under existing polyhypovitaminosis can lead to the deterioration of the sufficiency with fat-soluble vitamins.     

Use of thiamine for correcting the immune response during physical loading

A study was made of the effect of thiamine on the development of the immune response under exercise. It was established that the 4-hour swimming inhibited the development of the immune response to sheep red blood cells in Wistar rats fed about 40 g thiamine per day with the diet. Additional administration of 100 g vitamin increased the intensity of the immune response after exercise. The serum from the swimming rats suppressed the development of the immune response in intact animals. Thiamine did not produce any effect on the exercise-induced synthesis and release of immunosuppressant factors but reduced the sensitivity of effector cells of the humoral immune response to the action of those factors.     

Enzyme activity of gluconeogenesis in dietary thiamine deficiency

Activity of the main enzymes of gluconeogenesis under food thiamine deficiency was studied in tissues of satiated and 48-hour starved rats. Starvation of control rats (with no vitamin B1-deficiency) led to increased activity of glucose 6-phosphatase (G-6-P) in the liver, kidney and small intestinal mucosa, and of phosphoenolpyruvate carboxykinase (PEPCK) in the liver and kidneys. Fructose 1,6-diphosphatase (F-D-P) activity in the control animals was not changed in the liver and kidneys but decreased in the small intestinal mucosa. Starvation of the test animals (with vitamin B1-deficiency) was attended by increased G-6-P and PEPCK activity in the liver and kidneys, and F-D-P activity in the liver. Thiamine deficiency led to lowered G-6-P and F-D-P activities in the liver and kidneys and PEPCK in the liver of the test animals as compared to the control. The data obtained have evidenced disorders in the gluconeogenesis under conditions of vitamin B1-deficiency.     

Effect of dietary factor deficiency on the membranotoxic and cytostatic activity of splenocytes

The influence of alimentary factor deficiency on the membranotoxic and cytostatic action of splenocyte effectors was studied in VAG rats. Four groups of animals were kept on different rations during 60 days: group I received a balanced ration, group II was given a ration with essential amino acid deficiency, group III--with vitamin A and E deficiency, group IV--with essential amino acid and vitamin A and E deficiency (polyimbalance). It was shown that in polyimbalance and vitamin A and E deficiency the membranotoxic and cytostatic activity of splenocytes was decreased, the cytostatic action being more sensitive to the deficiency of these factors. Addition of interleukin-2 to the incubation mixture restored the membranotoxic activity up to the normal level. The immunological parameters studied were not substantially changed in the deficiency of essential amino acids. It is suggested that the disordered T-cell regulatory function of amplifiers, which are the main producers of interleukin-2, is one of the principal mechanisms decreasing the splenocyte membranotoxic activity.     

Adaptive processes occurring during the development of thiamine deficiency

In the presence of the total of the level of vitamin B1 derivatives, the liver shows an uniform decrease in the content of thiamine diphosphate (TDP) with phase changes in the activities of thiamine phosphokinase and thiamine pyrophosphatase. The activity of transketolase and the blood ratio of cholo- and apoform enzyme seen over time are liable to phase oscillations which are likely to mirror the involvement of the enzyme in TDP deposition and transport. The data obtained are regarded as evidence for adaptive shifts in the metabolism of thiamine proper, aimed at partial compensation for its deficiency by redistribution of the vitamin among different tissue of the body.     

Postruminal lysine and methionine infusion in steers fed a urea-supplemental diet adequate in sulfur

Postruminal utilization of methionine by growing steer calves fed ground shelled corn, urea, and cottonseed hulls adequate in sulfur was studied by abomasal infusion of graded quantities of methionine with lysine adequate. A 6 X 6 Latin square of treatments was replicated in which infusions provided lysine and methionine in grams per day: A) 0,0; B) 24,0; C) 24,4; D) 24,8; E) 24,12; and F) 24,12 plus 140 g sodium caseinate. Treatments were brought to volume in 2 liters of water and infused continuously over 24 h. Responses measured were nitrogen retention, urea nitrogen in plasma, and concentrations of free amino acids. Retention of nitrogen was increased in steers abomasally infused with lysine or lysine in combination with graded quantities of methionine. Infusion of 4, 8, or 12 g/day of methionine with constant lysine (24 g/day) did not alter nitrogen retained from lysine infused alone. Infusion of a lysine-methionine-sodium caseinate positive control raised nitrogen retention compared with no caseinate. Lysine of plasma was higher in treatments in which lysine was infused compared with the negative control. Methionine increased linearly with infusion of incremental quantities. Methionine was not limiting when infused prostruminally with adequate lysine to growing steers fed the urea-supplemented diet with sulfur adequate.     

Oxidation of methionine and cystine in foods treated with hydrogen peroxide

The damage to sulphur-containing amino acids in two experimental samples of casein and fish meal treated with hydrogen peroxide was studied. Methionine, cystine (cysteine), methionine sulphoxide (according to Neumann), methionine sulphone and cysteic acid contents were determined chemically. The nutritive value of proteins was determined biologically. In the treated samples, methionine appeared to be oxidised almost completely. The major part was oxidised to the methionine sulphoxide level. Both treated samples contained methionine sulphone and cysteic acid. It was noted that the percentage of total sulphur-containing amino acids being oxidised to methionine sulphone and cysteic acid was about the same as the percentage decrease in n.p.u. The results suggest that peptide-bound methionine sulphoxide is as available as peptide-bound methionine.     

Effect of Partial Methionine Oxidation on the Nutritional Quality of Soy Isolate and Casein

The bioavallabllity of methionine sulfoxide residues in two food proteins, casein and soy isolate, was determined in weanling (21- day-old) and mature rats (101-day-old). Methionine sulfoxide residues within these two proteins had no significant effect on protein digestibility in either group of rats or on the growth of mature rats, but slowed the growth of weanling rats. The impact of methionine sulfone on the protein efficiency ratio (PER) bioassay for protein nutritional quality, which uses weanling rats, was also measured. Results from this study indicated that for each 10% of the methionine residues which are present as partially oxidized methionlne sulfone, the PER of the protein is lowered by 0.085 units.     

Vitamin B 12 metabolism and the status of sulfhydryl groups in protein-choline deficiency in rats. Effects of methyl- and adenosylcobalamins]

The effect of low protein choline-deficient diet on total vitamin B12 content and individual cobalamin level in the blood serum and liver of rats was determined. Moreover the total and non-protein SH-group content and glutathione transferase activity in the liver of rats were studied. Total cobalamin content increased in the blood serum, but it did not change in the liver of rats fed choline-deficient low protein diet. Total and non-protein SH-group level as well as glutathione transferase activity in the liver decreased significantly. The causes of changes revealed are discussed. Methylcobalamin (but not adenosylcobalamin) administration normalized individual cobalamin level in the blood serum. Administration of both methylcobalamin and adenosyl-cobalamin resulted in total SH-group content restoration whereas non-protein SH-group level and glutathione transferase activity were restored only in methylcobalamin-treated rats.     

Effect of combined vitamin D and E deficiencies on calcium metabolism and bone tissue of the rat

In experiments on young rats a study was made of the influence of combined vitamin D and E deficiency on biochemical signs of rickets. It was shown that in intact animals vitamin E deficiency induced moderate hypocalcemia, a tendency to decreased Ca active transport in the small intestine and mineral saturation of the bone tissue, as well as a significantly increased Ca content in the skeletal muscles and heart. The concentration of 25-oxyvitamin D (25-OVD) in the blood serum of these animals was not changed. Combined vitamin D and E deficiency intensified disorders typical for rickets; sometimes synergy of such a negative effect was recorded. A delay in the recovery of Ca metabolism parameters, bone tissue condition and 25-OVD circulating concentration persisted, when the animals with vitamin D and E deficiency were injected cholecalciferol during 6 days. The data obtained have evidenced a possible role of vitamin E deficiency in the rickets development, that is, probably, mediated, to a certain extent, by its influence on metabolism and (or) biochemical function of vitamin D.     

Nature of the vitamin composition of mare's milk and koumiss depending on the time of year

It was shown that the content of vitamins E, C, thiamine, riboflavin and niacin in mare's milk and kumyss varies depending on the season. The highest level of vitamins E, C and niacin was noted in May-June. The technological processing of mare's milk leads to the decreased content of vitamin C and niacin. Mare's milk and kumyss were found to contain dehydroascorbic acid in a considerable amount, especially in summer.     

Preventive antioxidant effects of cocoa polyphenolic extract on free radical production and cognitive performances after heat exposure in Wistar rats

ABSTRACT:  The preventive effects of ACTICOA powder (AP), a cocoa polyphenolic extract, on free radicals produced by leucocytes in rats after heat exposure (HE) and its protective effects on subsequent cognitive impairments were assessed. AP or vitamin E, the antioxidant reference, was orally administered to rats for 14 d before HE at 40 °C temperature during 2 h. The day after HE, free radical production by leucocytes in rats treated with AP or vitamin E was significantly reduced as compared to control. Unlike controls, AP- and vitamin E-treated rats discriminated between active lever and inactive levers in a light extinction paradigm. In the Morris water maze, escape latencies before reaching the hidden platform by AP- and vitamin E-treated rats decreased throughout testing. The daily oral administration of AP or vitamin E protected rats from cognitive impairments after HE by counteracting the overproduction of free radicals.     

Proteinization and biotransformation of pantothenic acid in the liver during the activation of lipogenesis

White female rats received a balanced synthetic ration (control) or a ration devoid of pantothenic acid (PAA) during 3 weeks. After 36-hour fasting adaptive hyperlipogenesis was induced by feeding the animals with a high-carbohydrate ration, then [114-C]-PAA (sodium salt, 182 nmol/kg) was administered with intervals of 3, 6, 24 hours up to 1 hour before decapitation. Radioactivity of the rats' boiled liver extracts depended on the hyperlipogenesis stage, its level rose progressively, in the control and reached the maximum in PAA-deficient animals by hour 6 after the feeding resumption. The PAA-deficient animals possessed a high PAA-accumulating capacity of the liver and cytosole of the liver including non-covalent radionuclide binding by protein complexes. CoA-synthesizing capacity of the liver in the control animals, evaluated by the biotransformation of the labeled vitamin with CoA precursors of CoA, was intensified with the lipogenesis activation; in vitamin-deficiency CoA biosynthesis was accelerated more than two-fold as compared to the control at the initial and extended periods of hyperlipogenesis (3.6 h). The differences in proteinization and biotransformation of PAA in the liver of control and PAA-deficient animals disappeared by 25 h of adaptive hyperlipogenesis.     

Effect of physical loading of various intensities on the thiamine allowance and ascorbic acid content of the blood and adrenals of rats of different ages

Providing with thiamine and the content of ascorbic acid (AA) were studied in 250 male rats with respect to their age and depending on the duration of physical load. In all age groups (from 1 to 1.5 months, from 6 to 12 months and over 12 months) the physical load (swimming) led to a decrease of the body providing with thiamine, that was expressed in the reduction of its content in the blood and liver, in the lowering of transketolase activity and rising of the TDP effect. These changes were more pronounced at the early age and directly depended on the duration of physical load. Physical load induced more manifest reduction of the AA content in the blood of young rats, and in the adrenals of the older group animals. Vitamin B1 and C deficiency induced by high physical load necessitates its correction by administration of additional doses of the vitamins to the animals.     

Metabolism of B group vitamins in rats, receiving rations with various amounts of protein and amino acids under conditions of chronic aniline poisoning

The influence of the isocalorific rations with decreased (10%) or increased (32%) protein content, and addition of cystine, methionine and glutamic acid (100 mg/kg) on metabolism of vitamins B2, B6 and PP was studied in rats under conditions of experimental chronic aniline intoxication. Increased protein amount in the diet and addition of amino acids sharply raise vitamin B6 requirement; vitamin B2 requirement grows with the increase of protein fraction and methionine and glutamic acid addition. Providing with vitamin PP under these conditions rises. Chronic aniline intoxication negatively influences the vitamin status of the test animals. Providing with vitamin B6 is most sharply decreased. Glutamic acid shows "saving" influence with respect to vitamin B2. The effect of chronic aniline intoxication on providing with vitamin PP is most manifested in the redistribution of oxidized and reduced nicotine amide coenzymes in the liver in the direction of a relative growth of reduced NAD and NADP concentrations.