Thiamine In Rats Research Articles

The acute effect of thiamine on serum insulin levels and some biochemical parameters in excessive alcohol-consuming rats

There are studies that present metabolic disorders in alcohol drinkers are associated with thiamine deficiency. Therefore, in the present study, it was aimed to investigate the effectiveness of thiamine in rats with binge drinking model. For this purpose, total 21 spraque dawley rats were divided into three equal groups as control, alcohol and thiamine+alcohol groups. The thiamine+ethanol group was given thiamine at a daily dose of 100 mg/kg by oral gavage, starting 2 days before the ethanol administration. Alcohol and thiamine+alcohol groups were given 3.45g/kg/day ethanol as 20%. At the end of the study, while serum total bile acid, total bilirubin and insulin levels increased in rats in the alcohol group compared to the rats in the control group; total protein and albumin levels decreased (P<0.05). In the thiamine + alcohol group, LDL-cholesterol, total cholesterol, bile acid levels and AST enzyme activity increased, while ALT enzyme activity and total protein levels decreased compared to the control group (P<0.05). There was no statistically significant result in the values in the thiamine+alcohol group compared to the alcohol group. It has been concluded that acutely administered thiamine supplementation had no effect on alcohol-induced biochemical parameter changes in binge-drinking animals. In this sense, studies with longer-term thiamine use are needed.

Influence of Glucose Dosage in Parenteral Nutrition on Body Thiamine Levels in Rats.

The objective of this study was to determine the relationship between glucose dosage in parenteral nutrition and reductions in levels of body thiamine in rats. Vitamin-free infusions with differing amounts of glucose were administered to normal or thiamine-deficient rats for 5 days, after which urinary thiamine excretion and the amounts of thiamine in the blood, liver, brain, and skeletal muscles were measured. The total energy dosage was set at three levels (98, 140, and 196 kcal/kg), and the dose of amino acids was constant among all groups. Urinary thiamine excretions on Day 5 decreased with increasing glucose dosage in the infusions. In normal rats, the amount of thiamine in the blood and all organs decreased compared with the diet group; however, no significant differences were found among the infusion groups. In thiamine-deficient rats, on the other hand, the amount of thiamine in the liver and skeletal muscles did not differ significantly among infusion groups; however, the amount of thiamine in the brain and blood decreased with increasing glucose dosage. An organ-specific correlation was found between glucose dosage in infusions and reductions in levels of thiamine. To prevent thiamine deficiencies from affecting the central nervous system, greater caution must be exercised during high-caloric parenteral nutrition. However, a constant supply of thiamine seemed to be essential, irrespective of the amount of energy supplied via parenteral nutrition, to maintain a sufficient level of thiamine in the body.

Comparative Study of the Effects of Enzyme Inhibitors and Inducers on Serum and Tissue Availability of Thiamine After Single Oral Dose of the Pro-drug Benfotiamine in Rats.

Thiamine is known to have an important role in the protection of different types of cells and tissues against the damage produced by many drugs and toxins. The most important problem limiting the clinical applications of this approach is the poor absorption and bioavailability of thiamine from the sites of administration, a problem which can be solved by the use of the lipid soluble pro-drug for thiamine, benfotiamine. Accordingly, this project was designed to evaluate the serum and tissues availability of thiamine in rats after the administration of single oral dose of benfotiamine compared with that producedby the same oral dose of thiamine, in addition to study the effects of enzyme inducers and inhibitors in this respect utilizing HPLC technique. According to the results obtained in this study one can conclude that thiamine availability after administration of benfotiamine was more in serum, liver, kidney while in the brain more time may be required to reach maximum level.

Urinary thiamine excretion in the rat: Effects of furosemide, other diuretics, and volume load

Long-term furosemide therapy is associated with increased urinary loss of thiamine. To examine the mechanism of furosemide-induced urinary thiamine loss, we measured urinary excretion of thiamine in rats in response to increasing doses of furosemide, acetazolamide, chlorothiazide, amiloride, mannitol, and extracellular fluid (ECF) volume loading by saline infusion. All animals were in normal thiamine balance as reflected by a thiamine pyrophosphate effect (TPPE) of 2.25% ± 0.60% (mean ± SEM), and all had normal renal function. Urinary flow increased in response to diuretic administration in a dose-dependent manner, reaching (mean) peak urinary flow rates of 283 to 402 μL/min. Fractional excretion of sodium (FENa) exhibited the same pattern, reaching peak values of 12.3% to 23.2%. Urinary thiamine excretion increased in proportion to the incremental doses of diuretic agents, reaching (mean) maximal values of 7.44 to 9.34 pmol/min, with no significant difference (P = .11) between the various diuretics tested nor in response to saline loading. None of the diuretics tested differed in the effect on thiamine excretion, which was clearly flow dependent and only partially related to fractional sodium excretion. Urinary flow rate, being the single significant predictor, explained 78% (R2 = 0.78) of the variability in thiamine excretion rates. These findings indicate that urinary thiamine loss is caused by a nonspecific, flow-dependent mechanism common to all of the diuretics tested.

Minimum Thiamin Requirement of Weanling Sprague-Dawley Outbred Rats , ,

To determine the minimum thiamin requirement for maximal growth, two trials were conducted using male weanling Sprague-Dawley rats fed graded doses of thiamin from thiamin mononitrate as a component of a chemically defined diet. This diet included 16% amino acids, 72% sucrose and cornstarch and 5% soybean oil. Total weight gain and food intake were recorded over 2- (trial 1) or 3- (trial 2) wk periods. In trial 1, graded levels of thiamin were fed at 0, 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0 mg thiamin/kg diet, and growth rate reached a plateau in rats fed 0.50 mg thiamin/kg. In trial 2, lower doses of thiamin were fed (0, 0.25, 0.50, 0.75, 1.0, 4.0 and 5.0 mg/kg) to determine the minimum requirement for maximal growth. Using broken-line least-squares analysis, weight gain reached a plateau (6.8 g/d) at a thiamin concentration of 0.55 ± 0.07 mg/kg. No differences (P > 0.05) in weight gain, food intake or gain:food ratio were observed at thiamin levels at or above 0.5 mg/kg, but food intake was substantially lower (P < 0.05) in rats fed 0 and 0.25 mg thiamin/kg (9.9 and 13.4 g/d, respectively) than in rats fed higher doses of thiamin (16.1 g/d). Hepatic transketolase, a measure of enzymatic thiamin status, increased with dietary thiamin in rats fed diets containing 0–5.0 mg/kg thiamin. However, an inflection point occurred at 0.53 mg thiamin/kg, with the slope being eight times greater below than above the inflection point. The data suggest that the thiamin requirement for maximal growth of weanling rats fed a chemically defined diet is ∼0.55 mg thiamin/kg, which is substantially below the current National Research Council estimated requirement of 3.1 mg thiamin/kg diet.

Effect of cow's milk factors on the bioavailability of non-milk thiamine in rats

Summary - The influence of milk factors on the bioavailability of non-milk thiamine was assessed using thiamine-deficient young rats. Twenty-eight h dialysed raw cow's milk (3.5% fat) was used as the source of milk factors. Repletion test diets provided were (A) dialysed milk alone (59 119)bound thiamine, (B) dialysed milk (59 119) plus pure thiamine (256 119) or (C) pure thiamine (315 119) as thiamine source, for 21 d. Total hepatic thiamine content, erythrocyte transketolase (ETK) activity and TPP (thiamine pyrophosphate) effect on ETK activity were selected as response criteria. Group B receiving dialysed milk supplemented with pure thiamine had significantly (P 2-fold in the presence of milk factors.

Elevated blood pyruvate levels and decreased retention of thiamin in rats mildly depleted of vitamin B 12

Nine-moth-old rats that were mildly depleted of vitamin B 12 and their controls were subjected to 26 days of thiamin deficiency. All rats had been equilibrated with the control level of thiamin (500 μg/ 100 g diet) for the previous 8 months. The four subgroups (11 rats/ subgroup) included: controls (CC), vitamin B 12-depleted (BD), thiamin deficient (TD) and vitamin B 12 depleted rats made thiamin deficient (BD+TD). At the initiation of the thiamin deficiency period, BD-rats were excreting 3 times more methylmalonic acid than their controls. This was indicative of a significant, although mild, depletion of vitamin B 12. The mild depletion of vitamin B 12 (BD) led to a 49% increased loss of thiamin in urine, whereas 26 days of thiamin deficiency (TD and BD+TD) was accompanied by decreased losses of thiamin in urine. Urinary losses of thiamin were equivalent to 24% of ingested thiamin for controls (CC), but these losses of thiamin were doubled (46%) in rats depleted of vitamin B 12 (BD). Because of their reduced intakes of food, BD-rats received only 78% as much thiamin as the controls (CC), and they retained a similar relative amount (69%) of thiamin in their liver. Thiamin deficient rats (TD) retained only 7% as much thiamin in their liver. The least amount of thiamin was retained in liver when rats had a thiamin deficiency combined with the mild depletion of vitamin B 12 (BD+TD). The mild depletion of vitamin B 12 (BD) and thiamin deficiency (TD) promoted equivalent increases in blood pyruvate. Rats mildly depleted of vitamin B 12 have an inhibited ability to retain absorbed thiamin, and the resulting depletion of thiamin leads to major increases in blood pyruvate.

Biological Activity of 1,N6-Ethenothiamin, a Fluorescent Analog of Thiamin, in Rats

The ability of the recently synthesized fluorescent analog of thiamin, 1,N6-ethenothiamin, to substitute for thiamin in rats in vivo has been studied. 50 micrograms of ethenothiamin/100 g body weight/day injected in rats allowed about one-half the weight gain with 50 micrograms/100g/day of thiamin. The activities of the pyruvate and alpha-keto-glutarate dehydrogenases of liver mitochondria were partially restored by 50 micrograms/100g/day of ethenothiamin. Ethenothiamin at this level did not appear to restore the branched-chain alpha-keto acid dehydrogenase activities to any extent. When 150 micrograms of ethenothiamin/100g body weight/day was injected, growth was optimum, but these enzyme activities still did not achieve normal levels.

Effect of l- and d-tyrosine on in vitro transport and phosphorylation of thiamine in rats

1. 1. l-Tyrosine accelerates the in vitro absorption of thiamine in Wistar white rats' jejunum, whereas d-tyrosine has no effect on it. 2. 2. The respiratory activity of intestine mucosa is higher in rats treated with l-tyrosine compared to the control; the d-isomer causes no changes. 3. 3. l-tyrosine activates thiamine phosphorylation in jejunum mucosa, while d-tyrosine depresses the process. 4. 4. The content of FT and TT in intestine mucosa is higher when l-tyrosine is introduced in the jejunum and lower in presence of the d-isomer.

Resorption of vitamin B 1—XII. Changes in the resorption and the phosphorylation of thiamine in rats in relation to age

Age is an important factor in the process of thiamine resorption in the small intestine (jejunum-ileum) of rats. Thiamine transport rate through the intestinal wall is significantly lower in ageing rats (26 months old) as compared to young (3 and a half months old) animals. It has been determined that the alkaline phosphatase activity in the small intestine mucosa and the rate of thiamine resorption change unidirectionally. The phosphorus ester content of thiamine (TMP, TDP) and FT in the intestinal mucosa of ageing rats is lower, as compared to that of young rats. TTP is an exception, its content in the intestinal mucosa of ageing rats being higher. TMP, TDP, TTP and FT content in the liver tissue of young rats is higher than in ageing rats.

Metabolic Fate of the Benzoic acid Moiety of O, S-Dibenzoyl thiamine in Rats

Metabolic Fate of the Benzoic acid Moiety of O, S-Dibenzoyl thiamine in Rats

Metabolism of Thiamin in the Hyperthyroid Rat

The effect of physiological doses of thyroxine on the depletion of tissue thiamin and on the fate of 2-14C-thiazole thiamin in rats fed a thiamin-deficient diet was investigated. Thyroxine increased the rate of depletion of liver thiamin, but did not affect muscle thiamin or erythrocyte transketolase activity. The rate of excretion of labeled thiamin metabolites in rat urine and feces was independent of prior or subsequent thiamin status and was unaltered by thyroxine. In contrast, thyroxine increased the elimination rate of respiratory 14CO2 originating from labeled thiamin. On the basis of these findings, it is postulated that multiple tissue pools of thiamin are reflected by the urinary, fecal, and respiratory routes of elimination of thiamin metabolites and by the different rates of turnover of liver and muscle thiamin.

Studies on metabolism of thiamine in rats. I. Cleavage of thiamine molecule in vivo.

It was found that in the rat about 50% of orally administered thiamine was decomposed into 4-methyl-5β-hydroxyethylthiazole (HT) and pyrimidyl derivative. It was demonstrated that 2-methyl-4-amino-5-hydroxymethylpyrimidine (HMP) was formed from thiamine as one of pyrimidyl derivatives. However, the amount of excreted HMP was extremely small as compared to that of excreted HT. It was concluded that the main cleavage of thiamine was not a direct hydrolysis into HT and HMP.

Effect of Calcium, Phosphorus and Manganese on the Intestinal Synthesis of Thiamine in Rats

When rats were fed thiamine-inadequate diets containing different levels of calcium and phosphorus with or without manganese, the urinary and fecal excretion of thiamine increased in rats receiving a low level of calcium and phosphorus and supplementation of manganese to this diet resulted in more urinary and fecal thiamine excretion. Higher levels of calcium and phosphorus in the diets, with or without manganese, and diets without an added amount of these minerals decreased the urinary and fecal excretion of thiamine. The presence of manganese in the diets reduced the lactobacilli count in the cecum and increased the coliform count. Rats receiving low calcium and phosphorus diets with or without manganese stored more thiamine in the liver and cecum than did other groups, whereas no increase was noted in the thiamine content of the heart. This observation indicates that low dietary calcium and phosphorus, with or without manganese, enhanced thiamine synthesis by the intestinal flora. This thiamine might be ultimately available to rats after coprophagy.

Thiamine-sparing action of mustard and role of coprophagy.

THE presence of crucifer material in the diet is reported to increase the urinary and faecal excretion of thiamine with greater storage of the vitamin in viscera of rats1. We have also reported that 2 per cent mustard (Brassica nigra) replacing the same weight of sucrose in the thiamine-free diet enhanced the synthesis of thiamine in rats only when coprophagy was allowed2. The coliform count in the caeca of mustard-fed rats was also found to increase considerably. The question then arises whether the vitamin was absorbed in the gut immediately after synthesis or whether it was excreted in the faeces and was available only after the animal had eaten its faeces.

Inhibitory Effect of Sulfaguanidine on the Biosynthesis of Thiamine in Rats and the Beneficial Role of Penicillin and Hydrolyzed Glucose Cycloacetoacetate

Inhibitory Effect of Sulfaguanidine on the Biosynthesis of Thiamine in Rats and the Beneficial Role of Penicillin and Hydrolyzed Glucose Cycloacetoacetate

Effect of carbohydrates on the intestinal synthesis of thiamine in rats.

Effect of carbohydrates on the intestinal synthesis of thiamine in rats.

EFFECT OF OXYTHIAMINE ON BLOOD PYRUVATE-LACTATE RELATIONSHIPS AND THE EXCRETION OF THIAMINE IN RATS

EFFECT OF OXYTHIAMINE ON BLOOD PYRUVATE-LACTATE RELATIONSHIPS AND THE EXCRETION OF THIAMINE IN RATS

The Relation Between Urinary Excretion and Tissue Concentrations of Thiamine in Rats

The Relation Between Urinary Excretion and Tissue Concentrations of Thiamine in Rats