scholarly journals Vitamin D Metabolism

2021 ◽  
Author(s):  
Sezer Acar ◽  
Behzat Özkan
Keyword(s):  
Vitamin D ◽  
Bone Metabolism ◽  
Human Skin ◽  
Vitamin D3 ◽  
Ultraviolet Irradiation ◽  
Ultraviolet Rays ◽  
Vitamin D2 ◽  
Animal Tissues ◽  
Vitamin D Metabolism

Vitamin D plays an important role in bone metabolism. Vitamin D is a group of biologically inactive, fat-soluble prohormones that exist in two major forms: ergocalciferol (vitamin D2) produced by plants in response to ultraviolet irradiation and cholecalciferol (vitamin D3) derived from animal tissues or 7-dehydrocholesterol in human skin by the action of ultraviolet rays present in sunlight. Vitamin D, which is biologically inactive, needs two-step hydroxylation for activation. All of these steps are of crucial for Vitamin D to show its effect properly. In this section, we will present vitamin D synthesis and its action steps in detail.

scholarly journals Differential Effects of Oral Boluses of Vitamin D2 vs Vitamin D3 on Vitamin D Metabolism: A Randomized Controlled Trial

2019 ◽  
Vol 104 (12) ◽  
pp. 5831-5839 ◽  
Author(s):  
Adrian R Martineau ◽  
Kenneth E Thummel ◽  
Zhican Wang ◽  
David A Jolliffe ◽  
Barbara J Boucher ◽  
...  
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
Bolus Dose ◽  
Total Serum ◽  
Vitamin D2 ◽  
Serum Concentrations ◽  
Vitamin D Metabolism ◽  
Dihydroxyvitamin D3 ◽  
Differential Effects ◽  
The Mean

Abstract Context Vitamin D2 and vitamin D3 have been hypothesized to exert differential effects on vitamin D metabolism. Objective To compare the influence of administering vitamin D2 vs vitamin D3 on metabolism of vitamin D3. Methods We measured baseline and 4-month serum concentrations of vitamin D3, 25-hydroxyvitamin D3 [25(OH)D3], 25-hydroxyvitamin D2, 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3], 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3], and 4β,25-dihydroxyvitamin D3 [4β,25(OH)2D3] in 52 adults randomized to receive a total of four oral bolus doses of 2.5 mg vitamin D2 (n = 28) or vitamin D3 (n = 24) over four months. Metabolite-to-parent compound ratios were calculated to estimate hydroxylase activity. Pairwise before vs after comparisons were made to evaluate effects of vitamin D2 and vitamin D3 on metabolism of vitamin D. Mean postsupplementation metabolite-to-parent ratios were then compared between groups. Results Vitamin D2 was less effective than vitamin D3 in elevating total serum 25(OH)D concentration. Vitamin D2 suppressed mean four-month serum concentrations of 25(OH)D3, 24R,25(OH)2D3, 1α,25(OH)2D3, and 4β,25(OH)2D3 and mean ratios of 25(OH)D3 to D3 and 1α,25(OH)2D3 to 25(OH)D3, while increasing the mean ratio of 24R,25(OH)2D3 to 25(OH)D3. Vitamin D3 increased mean four-month serum concentrations of 25(OH)D3, 24R,25(OH)2D3, 1α,25(OH)2D3, and 4β,25(OH)2D3 and the mean ratio of 24R,25(OH)2D3 to 25(OH)D3. Participants receiving vitamin D2 had lower mean postsupplementation ratios of 25(OH)D3 to vitamin D3 and 1α,25(OH)2D3 to 25(OH)D3 than those receiving vitamin D3. Mean postsupplementation ratios of 24R,25(OH)2D3 to 25(OH)D3 and 4β,25(OH)2D3 to 25(OH)D3 did not differ between groups. Conclusions Bolus-dose vitamin D2 is less effective than bolus-dose vitamin D3 in elevating total serum 25(OH)D concentration. Administration of vitamin D2 reduces 25-hydroxylation of vitamin D3 and 1-α hydroxylation of 25(OH)D3, while increasing 24R-hydroxylation of 25(OH)D3.

Metabolism of vitamin D in patients with primary biliary cirrhosis and alcoholic liver disease

1985 ◽  
Vol 69 (5) ◽  
pp. 561-570 ◽  
Author(s):  
E. Barbara Mawer ◽  
H. J. Klass ◽  
T. W. Warnes ◽  
Jacqueline L. Berry
Keyword(s):  
Vitamin D ◽  
Liver Disease ◽  
Primary Biliary Cirrhosis ◽  
Alcoholic Liver Disease ◽  
Vitamin D3 ◽  
Control Group ◽  
Biliary Cirrhosis ◽  
Vitamin D2 ◽  
Dihydroxyvitamin D3 ◽  
Poor Renal Function

1. The metabolism of isotopically labelled vitamin D2 and D3 has been investigated in eight patients with primary biliary cirrhosis and in five controls. The concentration of labelled vitamin D2 was lower than that of vitamin D3 in serum of patients with primary biliary cirrhosis on days 1 and 2 after intravenous injection (P < 0.005 and P < 0.05, respectively) but no difference was seen in controls. 2. Similar amounts of labelled 25-hydroxyvitamin D2 and D3 were seen in serum of the control group; the same pattern was observed in the primary biliary cirrhosis group, and no significant differences were observed between the two groups. 3. In both control and primary biliary cirrhosis groups, the serum concentration of labelled 24,25-dihydroxyvitamin D2 exceeded that of 24,25-dihydroxyvitamin D3 (significant for controls on day 2, P < 0.02) but concentrations in the two groups were not different. 4. Concentrations of labelled 25,26-dihydroxyvitamin D3 were significantly higher than those of 25,26-dihydroxyvitamin D2 in the primary biliary cirrhosis group at all times and in the control group on days 2 and 3. Both 25,26-dihydroxyvitamin D2 and D3 were higher in the serum of patients with primary biliary cirrhosis than in controls (significant on day 1, P < 0.05). 5. Urinary excretion over days 0–3 of radioactivity from both vitamins D2 and D3 was significantly higher in the primary biliary cirrhosis group than in controls: 12.03 vs 1.80% for vitamin D2 and 8.98 vs 1.76% for vitamin D3(P < 0.005). Vitamin D2-derived urinary radioactivity in primary biliary cirrhosis correlated strongly with serum bilirubin (P = 0.005). 6. The metabolism of labelled vitamin D3 was studied in seven patients with alcoholic liver disease, three of whom showed low serum concentrations of labelled 25-hydroxyvitamin D3 suggesting impaired hepatic synthesis. The 25-hydroxylation response was quantified as the relative index of 25-hydroxylation and was significantly related to two other indices of liver function. It is concluded that impaired 25-hydroxylation of vitamin D may occur in alcoholic liver disease and results from hepatocellular dysfunction. 7. Less than the predicted amounts of 1,25-dihydroxyvitamin D3 were produced in four of the seven patients with alcoholic liver disease; this defect may be attributable in part to decreased precursor 25-hydroxyvitamin D and to poor renal function.

Effect of Phenobarbitone Treatment on Vitamin D Metabolism in Mammals

1974 ◽  
Vol 46 (4) ◽  
pp. 433-448 ◽  
Author(s):  
J. Silver ◽  
G. Neale ◽  
G. R. Thompson
Keyword(s):  
Vitamin D ◽  
Biological Activity ◽  
Silicic Acid ◽  
Vitamin D3 ◽  
Water Soluble ◽  
Prolonged Treatment ◽  
Vitamin D Metabolism ◽  
Silicic Acid Chromatography ◽  
Polar Metabolites ◽  
25 Hydroxycholecalciferol

1. The metabolism of radioactive cholecalciferol was studied in control and phenobarbitone-treated rats and pigs. 2. Treatment with phenobarbitone enhanced the appearance in plasma of 25-hydroxycholecalciferol (peak IV on silicic acid chromatography), and of more-polar metabolites (peak V), but not of the most-polar metabolites (peak VI). Peak IV had the chromatographic properties of authentic 25-hydroxycholecalciferol (25-HCC) and had biological activity. 3. There was no effect on the appearance of peaks V and VI in plasma after an injection of radioactive 25-HCC. 4. Treatment with phenobarbitone enhanced the excretion of metabolites of radioactive vitamin D3 in bile. These metabolites were largely water-soluble conjugates of peaks IV, V and VI, which included glucuronides. Peak IV in bile was not identical with 25-HCC. 5. Prolonged treatment with phenobarbitone depleted the tissue radioactivity of rats given radioactive vitamin D3.

Vitamin D – Funktionen und Versorgung

2017 ◽  
Vol 32 (02) ◽  
pp. 57-58
Author(s):  
Tilman Grune
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
Vitamin D2

Die Bezeichnung Vitamin D ist ein Sammelbegriff für verschiedene Substanzen, die aus Cholesterol (Vitamin-D3-Derivate) und Ergosterol (Vitamin-D2-Derivate) synthetisiert werden. Der Stoffwechsel des Vitamin D und die Bildung seiner Wirk- und Transportformen ist ausführlich beschrieben [1, 2] und soll deshalb hier nicht erwähnt werden – nur an die Notwendigkeit von UV-Strahlung für einen zentralen Syntheseschritt in der Haut sei erinnert. Da diese UV-Strahlung offensichtlich nicht unter allen Umständen ausreicht, ist Vitamin D ein essenzieller Nahrungsbestandteil.

scholarly journals Vitamin D metabolism in dogs and cats and its relation to diseases not associated with bone metabolism

2019 ◽  
Vol 104 (1) ◽  
pp. 322-342 ◽  
Author(s):  
Rafael V. A. Zafalon ◽  
Larissa W. Risolia ◽  
Vivian Pedrinelli ◽  
Thiago H. A. Vendramini ◽  
Roberta B. A. Rodrigues ◽  
...  
Keyword(s):  
Vitamin D ◽  
Bone Metabolism ◽  
Vitamin D Metabolism

Analysis of Vitamin D2 and Vitamin D3 in Fortified Milk Powders and Infant and Nutritional Formulas by Liquid Chromatography–Tandem Mass Spectrometry: Single-Laboratory Validation, First Action 2016.05

2016 ◽  
Vol 99 (5) ◽  
pp. 1321-1330 ◽  
Author(s):  
Brendon D Gill ◽  
Grant A Abernethy ◽  
Rebecca J Green ◽  
Harvey E Indyk
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
Multiple Reaction Monitoring ◽  
Reference Method ◽  
Vitamin D2 ◽  
Method Performance ◽  
Expert Review ◽  
Fortified Milk ◽  
Expert Review Panel ◽  
Single Laboratory

Abstract A method for the determination of vitamin D2 and vitamin D3 in fortified milk powders and infant and adult nutritional formulas is described. Samples are saponified at high temperature and lipid-soluble components are extracted into isooctane. A portion of the isooctane layer is transferred and washed, and an aliquot of 4-phenyl-1,2,4-triazoline-3,5-dione is added to derivatize the vitamin D to form a high-molecular-mass, easily ionizable adduct. The vitamin D adduct is then re-extracted into a small volume of acetonitrile and analyzed by RPLC. Detection is by tandem MS, using multiple reaction monitoring. Stable isotope-labeled vitamin D2 and vitamin D3 internal standards are used for quantitation to correct for losses in extraction and any variation in derivatization and ionization efficiencies. A single-laboratory validation of the method using AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) kit samples was performed and compared with parameters defined according to the vitamin D Standard Method Performance Requirements (SMPR®). Linearity was demonstrated over the range specified in the SMPR, with the LOD being estimated at below that required. Method spike recovery (vitamin D2, 97.0–99.2%; and vitamin D3, 96.0–101.0%) and RSDr (vitamin D3, 1.5–5.2%) were evaluated and compared favorably with limits in the vitamin D SMPR. Acceptable bias for vitamin D3 was demonstrated against both the certified value for National Institute of Standards and Technology 1849a Standard Reference material (P(α = 0.05) = 0.25) and AOAC INTERNATIONAL reference method 2002.05 (P(α = 0.05) = 0.09). The method was demonstrated to meet the requirements of the vitamin D SMPR as defined by SPIFAN, and was recently approved for Official First Action status by the AOAC Expert Review Panel on SPIFAN Nutrient Methods.

scholarly journals Effect of smoking on the serum levels of 25-hydroxyvitamin D depends on the assay employed

2010 ◽  
Vol 163 (6) ◽  
pp. 965 ◽  
Author(s):  
Guri Grimnes ◽  
Bjørg Almaas ◽  
Anne Elise Eggen ◽  
Nina Emaus ◽  
Yngve Figenschau ◽  
...  
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
Serum Levels ◽  
Ultraviolet B ◽  
Vitamin D2 ◽  
Related Article ◽  
Hydroxyvitamin D ◽  
Article Type ◽  
25 Hydroxyvitamin D ◽  
Uvb Exposure

The authors and the journal apologise for errors in the Introduction section of this paper published in the European Journal of Endocrinology 2010 vol 163 pp 339–348. Lines 11–14 of the Introduction section should read as follows:This reflects the amount of vitamin D ingested from food (ergocalciferol (vitamin D2) or cholecalciferol (vitamin D3)) and the amount of vitamin D produced in the skin during ultraviolet B (UVB) exposure (vitamin D3)and not as published.

scholarly journals Vitamin D Daily versus Monthly Administration: Bone Turnover and Adipose Tissue Influences

Nutrients ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1934 ◽  
Author(s):  
Luca Dalle Carbonare ◽  
Maria Valenti ◽  
Francesco del Forno ◽  
Giorgio Piacentini ◽  
Angelo Pietrobelli
Keyword(s):  
Vitamin D ◽  
Waist Circumference ◽  
Bone Turnover ◽  
Bone Metabolism ◽  
Vitamin D3 ◽  
Metabolic Diseases ◽  
Neurological Diseases ◽  
Protective Role ◽  
Vitamin D Levels ◽  
Monthly Administration

Vitamin D is involved in bone metabolism and in many various extra-skeletal diseases such as malabsorption syndromes, cardiovascular and metabolic diseases, cancer, and autoimmune and neurological diseases. However, data on the optimal route of administration are not consistent. The aims of our study were to analyze not only the influence of daily vs. monthly administration of vitamin D on bone metabolism and bone turnover, but also the effects of different routes of administration on fat mass in a cohort of adults with low levels of 25(OH) vitamin D3 at baseline. We analyzed 44 patients with hypovitaminosis at baseline and after six months of two different regimens of administration: seven drops (1750 IU)/day vs. 50,000 IU/month. We found that the two regimens were equivalent; 36 out of 44 patients reached the normal range of vitamin D after six months of treatment. Interestingly, the main determinant of vitamin D at baseline was the waist circumference. In addition, 22 patients treated by monthly regimen were evaluated after 18 months of treatment. At the end of follow-up, patients showed normal levels of vitamin D, with increased calcium levels and decreased bone turnover. Waist circumference also decreased. Our results support the efficacy of vitamin D3 given monthly both for correcting hypovitaminosis and for maintaining vitamin D levels. The relationship between serum 25(OH)vitamin D3 concentration and waist circumference supports vitamin D having a protective role in the current setting, since waist size is directly associated with the risk of cardiovascular and metabolic diseases.

Sign in / Sign up

Export Citation Format

Share Document