The Role of Vitamin B12 and Folic Acid in Hemato- and Other Cell-Poiesis

Herbert, Victor; Das, K. C.

doi:10.1016/s0083-6729(08)60071-0

Cited by 55 publications

(25 citation statements)

References 99 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1) (5). These data form the basis of the "methylfolate trap" hypothesis of cobalamin deficiency (6,7). Trapping folates as 5-methyltetrahydrofolate should lead to decreased purine, thymidylate, and S-adenosylmethionine synthesis (Fig.…”

Section: Introductionmentioning

confidence: 91%

Cobalamin inactivation decreases purine and methionine synthesis in cultured lymphoblasts.

Boss¹

1985

J. Clin. Invest.

View full text Add to dashboard Cite

The megaloblastic anemia of cobalamin deficiency appears secondary to decreased methionine synthetase activity. Decreased activity of this enzyme should cause 5-methyltetrahydrofolate to accumulate intracellularly, and consequently, decrease purine and DNA synthesis; this is the basis of the "methylfolate trap" hypothesis of cobalamin deficiency. However, only some of the clinical and biochemical manifestations of cobalamin deficiency can be explained by the methylfolate trap. We investigated cobalamin deficiency by treating cultured human lymphoblasts with N20 since N20 inhibits methionine synthetase activity by inactivating cobalamin. We found that 4 h of N20 exposure reduced rates of methionine synthesis by 89%. Rates of purine synthesis were not significantly reduced by N20 when folate and methionine were present at 100 IAM in the medium; however, at the physiologic methionine concentration of 10 uM, N20 decreased rates of purine synthesis by 33 and 57% in the presence of 100 AM folate and in the absence of folate, respectively. The dependency of rates of purine synthesis on methionine availability would be expected in cells with restricted methionine synthetic capacity because (a) methionine is the immediate precursor of S-adenosylmethionine, a potent inhibitor of 5-methyltetrahydrofolate synthesis; (b) methionine serves as a source of formate for purine synthesis; and (e) rates of purmne synthesis are dependent on the intracellular availability of essential amino acids. We conclude that cobalamin inactivation decreases purine synthesis by both methylfolate trapping and reduction of intracellular methionine synthesis.

show abstract

Section: Introductionmentioning

confidence: 91%

Cobalamin inactivation decreases purine and methionine synthesis in cultured lymphoblasts.

Boss¹

1985

J. Clin. Invest.

View full text Add to dashboard Cite

show abstract

“…Genetic "knockouts" of erythroid transcription factors, erythropoietin (EPO) or EPO receptor block erythroid development and result in severe anemia and embryonic lethality between Day 9.5 and Day 15.5 of gestation [19][20][21][22][23][24][25][26][27][28]. Iron, folate, and vitamin B 12 are also required for erythropoiesis [29] and must come from a maternal source. Because initiation of fetal liver erythropoiesis is occurring during this critical time for fetal survival in swine, failure of erythropoiesis may be involved in fetal mortality and reduction of litter size.…”

Section: Introductionmentioning

confidence: 99%

Uterine Environment and Breed Effects on Erythropoiesis and Liver Protein Secretion in Late Embryonic and Early Fetal Swine1

Pearson

Klemcke

Christenson

et al. 1998

Biology of Reproduction

View full text Add to dashboard Cite

In this study we investigated erythropoiesis and fetal liver protein secretion during late embryonic (Day 24 and Day 30) and early fetal (Day 40) development in pigs from domestic white crossbred (WC) gilts with a normal (intact; INT) or crowded (unilateral hysterectomized/ovariectomized; UHO) uterine environment, or from prolific Chinese Meishan (MS) gilts. Increased fetal weight, fetal liver weight, placental weight, total red blood cells, hematocrit, blood hemoglobin content, and maternal plasma erythropoietin (EPO) levels were observed as gestation advanced. Cultured fetal liver secretion of transferrin and a protein of Mr 12500 and pI 7.5 also increased as gestation advanced. Fetal plasma EPO declined between Day 30 and Day 40. Differential counts of circulating erythroid precursors revealed a decline in basophilic erythroblasts and polychromatic erythroblasts between Day 24 and Day 40, an increase in orthochromatic erythroblasts on Day 30 followed by a drop on Day 40, and an increase in the percentage of reticulocytes/ erythrocytes from < 1.0% to approximately 90% of circulating red blood cells between Day 24 and Day 40. Differences among the treatment groups included a lower fetal survival percentage in UHO (vs. INT or MS) on Day 40, and higher maternal hematocrits, fetal weights, fetal hematocrits, fetal EPO levels, and liver transferrin secretion in WC vs. MS pigs. MS pigs had a lower percentage of polychromatic erythroblasts overall and a higher percentage of orthochromatic erythroblasts on Day 24 followed by a higher percentage of erythrocytes on Day 40 than WC pigs, suggesting a more mature erythron (circulating red blood cells plus erythropoietic tissue) in the MS pigs. Covariate analysis indicated that MS had larger placentae per unit of body weight than did WC. Conclusions were that 1) Days 24-40 of gestation is a critical time for fetal erythropoiesis in pigs as well as survival in a crowded uterine environment, 2) the MS breed may differ in the development of the fetal erythropoietic system because of altered fetal or uterine physiology, and 3) the UHO procedure did not significantly affect erythropoiesis in the fetuses studied but did alter fetal survival and the relationship between fetal weight and both hematocrit and hemoglobin on Day 40.

show abstract

“…Folic acid is a B-complex vitamin and is necessary for the synthesis of RNA and DNA (Herbert and Das 1976) as well as proteins (Chang and Kaiser 1972), especially in tissue with a high rate of cellular division and growth. In young ruminants, concentrations of serum folates are very low during the first month of life but reach adult concentrations by 4 mo of age (Girard et al 1989).…”

mentioning

confidence: 99%

Plane of nutrition and folic acid supplementation between birth and four months of age on mammary development of dairy heifers

Petitclerc¹,

Dumoulin²,

Ringuet³

et al. 1999

Can. J. Anim. Sci.

View full text Add to dashboard Cite

. 1999. Plane of nutrition and folic acid supplementation between birth and 4 months of age on mammary development of dairy heifers. Can. J. Anim. Sci. 79: 227-234. Forty-seven dairy heifers of approximately 10 d of age were assigned randomly to a 2 × 2 factorial design to study the effects of folic acid supplementation (0 vs. 40 mg) administered weekly i.m. and levels of feed intake after weaning on mammary development. Folic acid treatment started immediately and all heifers were weaned 5 wk later. Heifers were then either fed ad libitum grass hay and concentrates or restricted to a body weight gain of approximately 700 g d -1 until slaughter at 4 mo of age. Average daily gain was affected by feed intake level after weaning (615 vs. 954 g d -1 ; P < 0.01); however, folic acid supplementation increased weight gain only during the 5-wk period following weaning (P < 0.05). Heifers fed ad libitum were 33 % heavier before slaughter (P < 0.001) but there was no effect due to folic acid supplementation (P > 0.05). There was no effect of treatments on serum prolactin and growth hormone concentrations (P > 0.05); overall, prolactin increased and growth hormone decreased over the 16-wk sampling period. However, serum IGF-1 concentrations were significantly higher in heifers fed ad libitum following weaning as compared with the feed-restricted animals (P < 0.001); overall, IGF-1 concentrations increased linearly between weeks 2 and 16 (P < 0.001). Plane of nutrition did not have any effect (P > 0.05) on the total volume of parenchymal tissue in the mammary gland (61.6 vs. 63.6 cm 3 ); however, ad libitum feeding increased significantly (P < 0.001) the volume of extraparenchymal tissue in the gland (262.0 vs. 1067.6 cm 3 ). After adjusting data for the difference in body weight at slaughter, the amount of parenchymal tissue was smaller in animals fed ad libitum (P < 0.05); this adjustment did not change the effect of plane of nutrition on mammary extraparenchymal tissue. In conclusion, a fast rate of gain after weaning up to 4 mo of age induced a large accumulation of mammary fat, but did not negatively affect the total amount of parenchymal tissue in the mammary gland of dairy heifers.Key words: Plane of nutrition, folic acid, mammary gland, IGF-1 Petitclerc, D., Dumoulin, P., Ringuet, H., Matte, J. et Girard, J. 1999. Taux de croissance et supplémentation en acide folique entre la naissance et l'âge de 4 mois sur le développement de la glande mammaire de génisses laitières. Can. J. Anim. Sci. 79: 227-234. Quarante-sept génisses âgées approximativement de 10 jours ont été distribuées aléatoirement selon un dispositif factoriel 2 × 2. Les deux facteurs étudiés ont été la quantité d'acide folique injectée i.m. par semaine (0 ou 40 mg) pendant 16 semaines et le niveau d'alimentation suivant le sevrage. Suite au sevrage, les génisses ont été alors alimentées à volonté de foin et de concentrés ou restreintes pour permettre un gain de poids moyen de 700 g jour -1 jusqu'à leur abattage à l'âge de quatre mois. Le gain moyen quot...

show abstract

The Role of Vitamin B12 and Folic Acid in Hemato- and Other Cell-Poiesis

Cited by 55 publications

References 99 publications

Cobalamin inactivation decreases purine and methionine synthesis in cultured lymphoblasts.

Cobalamin inactivation decreases purine and methionine synthesis in cultured lymphoblasts.

Uterine Environment and Breed Effects on Erythropoiesis and Liver Protein Secretion in Late Embryonic and Early Fetal Swine1

Plane of nutrition and folic acid supplementation between birth and four months of age on mammary development of dairy heifers

Contact Info

Product

Resources

About