scholarly journals Possible interrelationship between vitamins E and b12 in the disturbance in methylmalonate metabolism in vitamin E deficiency

1978 ◽  
Vol 172 (1) ◽  
pp. 115-121 ◽  
Author(s):  
A S Pappu ◽  
P Fatterpaker ◽  
A Sreenivasan
Keyword(s):  
Vitamin E ◽  
Urinary Excretion ◽  
Vitamin B12 ◽  
Rat Liver ◽  
Vitamin B12 Deficiency ◽  
Vitamin E Deficiency ◽  
B12 Deficiency ◽  
Coenzyme Form

1. The disturbance in 2-methylmalonate metabolism resulting in its increased urinary excretion observed in vitamin E deficiency is not caused by increased formation of methylmalonate from propionate as is evident from the activity of the enzyme propionyl-CoA carboxylase (EC 6.4.1.3), but can be traced to an impairment in the conversion of methylmalonate into succinate by the vitamin B12-requiring enzyme, methylmalonyl-CoA mutase (EC 5.4.99.2) in rat liver. 2. It is shown that the decrease in the activity of methylmalonyl-CoA mutase in vitamin E deficiency is not a consequence of a secondary vitamin B12 deficiency. Peroxidative destruction of the coenzyme in vitamin E deficiency was also ruled out. The results suggest a defect in the conversion of cyanocobalamin into its coenzyme form.

scholarly journals Factors affecting formiminoglutamic acid excretion in vitamin B12 deficiency

1970 ◽  
Vol 116 (4) ◽  
pp. 681-688 ◽  
Author(s):  
Hedley R. Marston ◽  
Shirley H. Allen
Keyword(s):  
Urinary Excretion ◽  
Vitamin B12 ◽  
Vitamin B12 Deficiency ◽  
Acid Excretion ◽  
Factors Affecting ◽  
Methyl Donors ◽  
Pteroylglutamic Acid ◽  
B12 Deficiency ◽  
Acid Status

1. Formiminoglutamic acid, a product of the catabolism of histidine, is excreted in abnormally large amounts in the urines of vitamin B12-deficient rats and of vitamin B12-deficient sheep; the excretion is reduced to negligible amounts after administration of vitamin B12. 2. After administration of certain methyl donors to vitamin B12-deficient rats or sheep urinary excretion of formiminoglutamic acid is temporarily decreased. 3. Irrespective of the pteroylglutamic acid status of the animals neither vitamin B12-deficient rats nor vitamin B12-deficient sheep have the ability to deal efficiently with histidine. 4. In sheep, urinary excretion of formiminoglutamic acid is increased after administration of aminopterin; treatment with pteroylglutamic acid restores the ability of the animal to deal with the catabolic products of histidine. 5. The possible functions of vitamin B12 and methionine in relieving a virtual deficiency of pteroylglutamic acid are discussed.

scholarly journals Folic acid metabolism in vitamin B12-deficient sheep. Depletion of liver folates

1973 ◽  
Vol 136 (2) ◽  
pp. 279-293 ◽  
Author(s):  
Richard M. Smith ◽  
William S. Osborne-White
Keyword(s):  
Urinary Excretion ◽  
Vitamin B12 ◽  
Acid Metabolism ◽  
Vitamin B12 Deficiency ◽  
Deficient Diet ◽  
Severe Vitamin ◽  
Quantitative Estimates ◽  
Folic Acid Metabolism ◽  
B12 Deficiency ◽  
Microbiological Assays

1. Metabolism of folate was studied in six ewes in an advanced state of vitamin B12 deficiency as judged by voluntary food intake and in their pair-fed controls receiving vitamin B12. A group of four animals that were maintained throughout the experiment at pasture was also studied. 2. After 34–40 weeks on the cobalt-deficient diet urinary excretion of formiminoglutamate by four deficient animals was about 3.2mmol/day and this was not significantly decreased by injection of three of them with about 4.5μg of [2-14C]folate/kg body weight per day for 5 days. Three days after the last injection retention of [2-14C]folate by the livers of the deficient animals (5.5% of the dose) was lower than that of their pair-fed controls (26% of the dose) but there was no evidence of net retention of injected folate in the livers of either group. Urinary excretion of 14C indicated that renal clearance of folate may have been impaired in very severe vitamin B12 deficiency. 3. As estimated by microbiological assays total folates in the livers of animals at pasture (12.9μg/g) included about 24% of 5-methyltetrahydrofolate as compared with about 72% of a total of 12.5μg/g in three further ewes fed on a stock diet of wheaten hay-chaff and lucerne-chaff. Liver folates of vitamin B12-deficient animals (0.5μg/g) included about 88% of 5-methyltetrahydrofolate as compared with about 51% of a total of 5.2μg/g in pair-fed animals treated with vitamin B12. 4. Chromatography of liver folates of the pair-fed animals permitted quantitative estimates of the pteroylglutamates present. The results showed that the vitamin B12-deficient livers were more severely depleted of tetrahydrofolates and formyltetrahydrofolates than of methyltetrahydrofolates and that as the deficiency developed they were more severely depleted of the higher polyglutamates than of the monoglutamate within each of these classes. Results from animals injected with [2-14C]folate indicated an impairment of the exchange between pteroylmonoglutamates and pteroylpolyglutamates in the livers of deficient animals. 5. In vitamin B12-deficient animals with food intakes below 200g/day some of the liver folates were not completely reduced and some degradation of pteroylpolyglutamates was detected. The latter condition may have been associated with fatty liver. 6. The results are discussed in relation to current theories of vitamin B12–folate interactions.

scholarly journals Vitamin B12 deficiency and the excretion of ether-soluble acids in the rat

1967 ◽  
Vol 21 (2) ◽  
pp. 309-314 ◽  
Author(s):  
B. K. Armstrong
Keyword(s):  
Urinary Excretion ◽  
Vitamin B12 ◽  
Methylmalonic Acid ◽  
Vitamin B12 Deficiency ◽  
Vitamin B ◽  
B12 Deficiency ◽  
Males And Females

1. Urinary excretion of total ether-soluble acids and of methylmalonic acid was studied in rats on vitamin B12-deficient diets with and without a vitamin B12 supplement.2. It was shown that urinary excretion of total ether-soluble acids and methylmalonic acid was increased in vitamin B12-deficient rats and that this increase was somewhat variable between individual animals, males and females, and rats from different litters.3. The increased excretion of these acids could readily be reversed by supplementing the diet with vitamin B12.

scholarly journals The Plasma Clearance and Urinary Excretion of Parenterally Administered 58Co B12

Blood ◽  
1956 ◽  
Vol 11 (1) ◽  
pp. 31-43 ◽  
Author(s):  
D. L. MOLLIN ◽  
W. R. PITNEY ◽  
S. J. BAKER ◽  
J. E. BRADLEY
Keyword(s):  
Urinary Excretion ◽  
Vitamin B12 ◽  
Plasma Clearance ◽  
Vitamin B12 Deficiency ◽  
Normal Subjects ◽  
Normal Serum ◽  
Chronic Myelocytic Leukemia ◽  
Intravenous Injections ◽  
Myelocytic Leukemia ◽  
B12 Deficiency

Abstract Intravenous injections of 1.5 µg. of 58Co B12 were given to subjects with normal serum B12 concentrations, to patients with vitamin B12 deficiency and to patients with chronic myelocytic leukemia. The rate of plasma clearance of radioactivity after this dose was slowest in patients with chronic myelocytic leukemia and patients with pernicious anemia in severe relapse. In patients with vitamin B12 deficiency, serum B12 concentrations were estimated microbiologically at frequent intervals after the injection. There was a good correlation between the results obtained by microbiological assay and as calculated from plasma radioactivity. Significant differences were not observed between the urinary excretion of radioactivity by normal subjects and patients with B12 deficiency.

55: The Risk of Vitamin B12 Deficiency is Low after Ileal Orthotopic Bladder Substitution

2004 ◽  
Vol 171 (4S) ◽  
pp. 15-15
Author(s):  
Urs E. Studer ◽  
Richard Aebischer ◽  
Katharina Ochsner ◽  
Werner W. Hochreiter
Keyword(s):  
Vitamin B12 ◽  
Vitamin B12 Deficiency ◽  
B12 Deficiency ◽  
Bladder Substitution

Bioavailability of Vitamin B12

2010 ◽  
Vol 80 (45) ◽  
pp. 330-335 ◽  
Author(s):  
Lindsay Helen Allen
Keyword(s):  
Vitamin B12 ◽  
Vitamin B12 Deficiency ◽  
The Elderly ◽  
Radioactive Isotopes ◽  
Animal Source Foods ◽  
Dietary Requirements ◽  
In Vivo Labeling ◽  
B12 Deficiency ◽  
Vitamin B12 Malabsorption

Vitamin B12 deficiency is common in people of all ages who consume a low intake of animal-source foods, including populations in developing countries. It is also prevalent among the elderly, even in wealthier countries, due to their malabsorption of B12 from food. Several methods have been applied to diagnose vitamin B12 malabsorption, including Schilling’s test, which is now used rarely, but these do not quantify percent bioavailability. Most of the information on B12 bioavailability from foods was collected 40 to 50 years ago, using radioactive isotopes of cobalt to label the corrinoid ring. The data are sparse, and the level of radioactivity required for in vivo labeling of animal tissues can be prohibitive. A newer method under development uses a low dose of radioactivity as 14C-labeled B12, with measurement of the isotope excreted in urine and feces by accelerator mass spectrometry. This test has revealed that the unabsorbed vitamin is degraded in the intestine. The percent bioavailability is inversely proportional to the dose consumed due to saturation of the active absorption process, even within the range of usual intake from foods. This has important implications for the assessment and interpretation of bioavailability values, setting dietary requirements, and interpreting relationships between intake and status of the vitamin.

Increased monocyte to HDL cholesterol ratio in vitamin B12 deficiency: is it related to cardiometabolic risk?

2020 ◽  
pp. 1-8
Author(s):  
Sanem Kayhan ◽  
Nazli Gulsoy Kirnap ◽  
Mercan Tastemur
Keyword(s):  
Risk Factors ◽  
Blood Pressure ◽  
Uric Acid ◽  
Vitamin B12 ◽  
Cardiometabolic Risk ◽  
Vitamin B12 Deficiency ◽  
Left Ventricular ◽  
Cardiometabolic Risk Factors ◽  
B12 Deficiency ◽  
Deficiency Group

Abstract. Vitamin B12 deficiency may have indirect cardiovascular effects in addition to hematological and neuropsychiatric symptoms. It was shown that the monocyte count-to-high density lipoprotein cholesterol (HDL-C) ratio (MHR) is a novel cardiovascular marker. In this study, the aim was to evaluate whether MHR was high in patients with vitamin B12 deficiency and its relationship with cardiometabolic risk factors. The study included 128 patients diagnosed with vitamin B12 deficiency and 93 healthy controls. Patients with vitamin B12 deficiency had significantly higher systolic blood pressure (SBP), diastolic blood pressure (DBP), MHR, C-reactive protein (CRP) and uric acid levels compared with the controls (median 139 vs 115 mmHg, p < 0.001; 80 vs 70 mmHg, p < 0.001; 14.2 vs 9.5, p < 0.001; 10.2 vs 4 mg/dl p < 0.001; 6.68 vs 4.8 mg/dl, p < 0.001 respectively). The prevalence of left ventricular hypertrophy was higher in vitamin B12 deficiency group (43.8%) than the control group (8.6%) (p < 0.001). In vitamin B12 deficiency group, a positive correlation was detected between MHR and SBP, CRP and uric acid (p < 0.001 r:0.34, p < 0.001 r:0.30, p < 0.001 r:0.5, respectively) and a significant negative correlation was detected between MHR and T-CHOL, LDL, HDL and B12 (p < 0.001 r: −0.39, p < 0.001 r: −0.34, p < 0.001 r: −0.57, p < 0.04 r: −0.17, respectively). MHR was high in vitamin B12 deficiency group, and correlated with the cardiometabolic risk factors in this group, which were SBP, CRP, uric acid and HDL. In conclusion, MRH, which can be easily calculated in clinical practice, can be a useful marker to assess cardiovascular risk in patients with vitamin B12 deficiency.

Utility of measuring vitamin B12 and its active fraction, holotranscobalamin, in neurological vitamin B12 deficiency syndromes

2009 ◽  
Vol 36 (S 02) ◽  
Author(s):  
W Schrempf ◽  
V Neumeister ◽  
M Eulitz ◽  
G Siegert ◽  
H Reichmann ◽  
...  
Keyword(s):  
Vitamin B12 ◽  
Vitamin B12 Deficiency ◽  
Active Fraction ◽  
B12 Deficiency
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