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At least 91 records · Page 5Linked to original sources
PubMed1965

THE EFFECT OF VITAMIN B 12 AND BIOTIN ON THE METABOLISM OF VITAMIN B 12 IN BIOTIN-DEFICIENT RATS.

1. The effect of the administration of vitamin B(12) and biotin on the metabolic pattern of vitamin B(12) in biotin-deficient rats was studied. 2. No significant changes in the absorption and excretion of orally administered [(58)Co]vitamin B(12) were noted either in vitamin B(12)-treated and or in biotin-fed rats. A significant decrease of the uptake of orally given [(58)Co]vitamin B(12) was observed in the liver and kidneys of biotin-treated rats, whereas an increase of uptake in the kidneys of vitamin B(12)-treated rats was noted as compared with biotin-deficient animals. 3. No significant difference in the excretion of radioactivity was noted between biotin deficient and biotin-fed rats when [(58)Co]vitamin B(12) was administered by injection. A small decrease was observed in vitamin B(12)-treated rats. The retention of injected [(58)Co]vitamin B(12) by major organs of biotin-treated rats was lower than that of biotin-deficient rats. A lower content of [(58)Co]vitamin B(12) was also detected in the organs, with the exception of the kidneys, of vitamin B(12)-treated rats. 4. These results are discussed in terms of an interrelationship between biotin and vitamin B(12).

Animals↗
PubMed1988

B vitamins suppress spinal dorsal horn nociceptive neurons in the cat.

To explore the role of vitamin B in neural mechanisms of analgesia, we investigated the effect of a compound of vitamins B1, B6 and B12 (Neurobion, E. Merck) on the nociceptive responses of single neurons in the spinal cord dorsal horn in anesthetized cats. Intrathecal superfusion of Neurobion, using a small pool placed on the spinal surface, produced a significant dose-dependent depression in the responses evoked by noxious skin heating (50 or 52 degrees C, 10 s) of hindfoot skin, but not of spontaneous activity in dorsal horn neurons. These results indicate that the therapeutic effect of vitamin B compounds in the clinical management of pain may involve a suppression of nociceptive transmission at the spinal level.

Animals↗
PubMed1981

Effects of vitamin B-6 deficiency during lactation on the vitamin B-6 content of milk, liver and muscle of rats.

Effects of a dietary deficiency of vitamin B-6 imposed during the lactation period on the level of this vitamin in milk, liver and muscle were assessed in rats. A control diet (vitamin B-6 free basal diet supplemented with 10 mg pyridoxine . HCl/kg) was fed to all rats just before and during the gestation period. On day 1 of lactation, dams were randomly assigned to three dietary treatment groups: deficient (vitamin B-6 free basal diet), control or restricted control (control diet restricted in quantity to that consumed by the deficient group). Levels of total vitamin B-6 in milk, liver and muscle were determined by microbiological assay on days 1, 6, 16 and 21 of lactation. On day 6, the concentration of vitamin B-6 in milk of deficient dams was less than 20% of control or restricted control values. The low level of vitamin B-6 in milk of the deficient group continued to be evident on days 16 and 21 whereas in control and restricted control groups the vitamin content increased on days 16 and 21 compared to the values on day 6. In contrast to the low level of vitamin B-6 content observed in milk on day 6 in the deficient group, the vitamin content in liver of this group was approximately 75% of control or restricted control values, and the vitamin content in muscle was not significantly altered by the deficiency. Hence, milk was effected sooner by the deficiency and was an earlier indicator of impending vitamin B-6 deficiency than was liver or muscle tissues.

Animals↗
PubMedDate not supplied

[Effect of dietary protein and vitamin B group deficiencies on the calcium-binding protein content in the mucosa of the small intestine].

The content of calcium-binding protein (CBP) and calcium-binding activity of small intestinal mucoproteins were examined in growing male rats kept on the diet deficient in proteins and group B vitamins (thiamine, riboflavin and pyridoxine). CBP was isolated by means of electrophoresis in 7.5% polyacrylamide gel. Calcium-binding activity of mucoproteins was explored with the aid of dialysis followed by complexonometric titration. The deficiency of food proteins was shown to lead to substantial changes in the content of vitamin D-dependent CBP and calcium-binding activity of mucoproteins. The deficiency of group B vitamins did not produce any appreciable influence on the content of CBP or calciumbinding activity of total mucoproteins.

Animals↗
PubMed2000

Blood homocysteine and vitamin B levels are not associated with cognitive skills in healthy normally ageing subjects.

Increased plasma total homocysteine (tHcy) levels are a known risk factor for vascular disease and have been reported in association with cognitive impairment of old age. Alternatively, however, increased tHcy levels may simply be an indicator of B vitamin deficiency. We evaluated the relationship between plasma tHcy levels, serum vitamin B12 and folate levels, and the scores at a battery of neuropsychological tests in 54 healthy cognitively normal subjects aged 65 years and over. Hyperhomocysteinemia prevalence (plasma tHcy>15 micromol/L) was about 24%. In univariate analysis, vitamin B12 levels were associated with both verbal memory and visuo-spatial skills, whereas no association was found between psychometric test scores and folate levels or tHcy levels. However, none of the univariate associations of neuropsychological test scores and serum B12 vitamin levels was confirmed when adjusting for age, education and other confounding variables. In conclusion, although a relationship between homocysteine, B vitamins and poor cognitive skills in the elderly is plausible, this study does not suggests that such relationship is biologically important.

Aged↗
PubMed1979

Preparation of vitamin B-12-free serum for the use in vitamin B-12 radioassays.

In radioassays for serum vitamin B-12, the separation of free and bound vitamin is usually made with charcoal absorption. The specificity of this separation depends on the amount of charcoal and the protein content and constitution of the medium. The large difference in protein concentration between the samples for the dilution curve and the serum samples introduces an uncontrolled variable in the test. In order to equalize the experimental circumstances, the standard dilutions were made in serum freed from vitamin B-12 after boiling the serum for 20 min in a 4-fold dilution with glutamic acid buffer at pH 3.3 and subsequent passage over a CH-Sepharose 4-B column complexed with hog intrinsic factor (IF). The vitamin B-12-binding capacity of such an affinity column prepared from 1 g CH-Sepharose and 20 mg IF, suffices for the absorption of vitamin B-12 in 3000 ml serum from which 300 series of vitamin B-12 standard solutions can be made. Our first results with this method confirm that the charcoal absorption radioassay has become more accurate by the use of vitamin B-12-free serum in the standard dilutions.

Charcoal↗
PubMed1982

Release of vitamin B-12 in vitro from intrinsic factor-vitamin B-12 complex. Purification and characterization of a releasing factor from rat ileal brush border.

Vitamin B-12 is released from the purified gastric intrinsic factor-[57Co]vitamin B-12 (intrinsic factor-[57Co]vitamin B-12) complex, when incubated with rat intestinal mucosa. Maximum specific activity for splitting the complex is localized in ileal brush border. Release of [57Co]vitamin B-12 is not due to its mere exchange during incubation with endogenous non-radioactive vitamin B-12. The splitting process has specific requirement for Ca2+ and ATP and it is thermolabile, time- as well as temperature-dependent. It is also inactivated by the presence of p-chloromercuribenzoate. Further, the vitamin B-12-releasing factor has been isolated from solubilized brush border and is purified 70-fold by (NH4)2SO4 precipitation, gel filtration and Con. A-Sepharose 4B affinity chromatography. In SDS-polyacrylamide gel electrophoresis, it is resolved into a single band of about 25 kDa, indicating its purity. The releasing factor exhibits maximum activity at pH 7.4; isoelectric focusing reveals only one major form with pI 7.52. With intrinsic factor-[57Co]vitamin B-12-complex as the substrate, apparent Km and Vmax values obtained are 128.2 X 10(-12) M/I and 117.6 pg X h-1 100 micrograms protein, respectively. Amino acid and carbohydrate analyses reveal the glycoprotein nature of the factor. Intrinsic factor-[57Co]vitamin B-12 complex is not susceptible to unspecific proteolytic digestion. Similarly, the releasing factor does not hydrolyse other proteins. Thus, the observed substrate-specificity of the releasing factor differentiates it from other known proteolytic enzymes of ileal brush borders.

Adenosine Triphosphate↗
PubMed1991

Response of vitamin B-6 content of muscle to changes in vitamin B-6 intake in men.

Previous reports indicated that in growing rats the vitamin B-6 pool in muscle was relatively stable during deficiency but increased in response to increased vitamin B-6 intake. To determine whether human muscle would show a similar response 10 college-aged males received a low vitamin B-6 diet (1.76 mumol/d) for 6 wk followed by 6 wk on a self-selected diet supplemented with 0.98 mmol pyridoxine HCl/d. During depletion, excretion of pyridoxic acid rapidly adjusted to approximate the intake. Plasma pyridoxal phosphate concentrations at the end of the baseline, depletion, and supplementation periods were 81 +/- 51, 9 +/- 3, and 455 +/- 129 nmol/L, respectively, whereas muscle concentrations were 21 +/- 9, 20 +/- 4, and 25 +/- 7 nmol/g, respectively and total vitamin B-6 in muscle was 28 +/- 10, 27 +/- 4, and 35 +/- 10 nmol/g, respectively. These data provide further confirmation that the vitamin B-6 pools in skeletal muscle are resistant to depletion. They also demonstrate that in humans with constant body weight, vitamin B-6 supplementation is not associated with marked increases in vitamin B-6 in muscle.

Adult↗
PubMed2007

Effects of high-level dietary B-vitamins on performance, body composition and tissue vitamin contents of growing/finishing pigs.

Forty-eight growing pigs were randomly assigned to five dietary groups and penned individually. They received a diet based on barley, wheat, corn and soya bean meal according to requirement. The experimental groups were supplemented with 400% or 800% of vitamins B(2), B(6) and pantothenic acid, or 400% or 800% of biotin, while all other vitamins were administered according to requirement. Growth performance, carcass characteristics, aspartate aminotransferase (AST), and content of vitamins in blood, liver and muscles were recorded. Growth performance showed no influence of supplementation, while backfat thickness in the group with 800% B(2)/B(6)/pantothenic acid was significantly higher. Content of B(2) in blood, liver and muscle was similar in all groups. Content of B(6) in blood and liver showed significant differences according to supplementation. The content of vitamin B(6) in muscle in the experimental groups was significantly higher than that in the control group. The content of pantothenic acid in blood and muscle in the experimental groups was significantly higher, while in liver all groups were significantly influenced by the supplementation level. Biotin content in liver showed no influence, but the content in plasma was significantly higher in the experimental groups and the content in muscle was significantly higher according to supplementation. The activity of AST showed no significant influence of the dietary vitamin level, but it was obviously decreased in the groups supplemented with biotin. The findings indicate that the dietary supplementation of vitamin B(2), B(6), pantothenic acid and biotin could not improve performance, but the contents in blood, liver and muscle.

Animal Feed↗