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At least 19 recordsLinked to original sources
PubMed2005

[Determination of vitamins D2, vitamin D3 in cosmetics by high performance liquid chromatography].

OBJECTIVE: A high performance liquid chromatography method was used to detect vitamins D2 and vitamin D3, which is useful to know the use of vitamins D2 and vitamin D3 in cosmetics, prohibit the influx of cosmetics containing vitamins D2 and vitamin D3 to cosmetic market, safeguard the health of consumers. METHODS: A high performance liquid chromatography method was established for determination of vitamins D2 and vitamin D3 in cosmetics. The separation condition was optimized by trying different type of columns and mobile phases. RESULTS: The experiment goes on a Alltima C18 column (250 mm x 4.6 mm I. D., 5 microm)using methanol-acetonitrile (90: 10) as mobile phase at a flow rate of 1.0 ml/min, with the column temperature 25 degrees C and detection wave 265nm. The liner range is from 0.5 mg/L to 100 mg/L with good relationship. The detection limit of vitamin D2 is 0. 12 mg/L, the precision is less than 3.8% and recovery varies from 94.2% to 101.4%, while the detection limit of vitamin D3 is 0.06 mg/L, the precision is less than 3.5% and recovery varies from 91.6% to 97.2%. CONCLUSION: The method is simple, precise and accurate, which is suitable for the determination of vitamins D2 and vitamin D3 in cosmetics.

Cholecalciferol↗
PubMed1983

Individual quantitation of vitamin D2, vitamin D3, 25-hydroxyvitamin D2, and 25-hydroxyvitamin D3 in human milk.

Extraction, lipid-reduction, and chromatographic methods suitable for the resolution and subsequent quantitation of vitamin D2, vitamin D3, 25-hydroxyvitamin D2, and 25-hydroxy-vitamin D3 from human milk are described. This procedure utilizes a methanol:methylene chloride extraction, precipitation of unwanted lipids with cold methanol and ether, backwash with alkaline buffer, silica Sep-Pak preparative chromatography, normal- and reverse-phase high-performance liquid chromatography with final quantitation of the antirachitic sterols by competitive protein binding assay. The described assay was used to determine these antirachitic sterols in milk from women receiving various supplements of vitamin D or undergoing ultraviolet phototherapy.

Cholecalciferol↗
PubMed1986

Serum vitamin D2 and vitamin D3 metabolite concentrations and absorption of vitamin D2 in elderly subjects.

The serum vitamin D2 and vitamin D3 metabolite concentrations and intestinal absorption of vitamin D2 were determined in healthy ambulatory and chronically institutionalized elderly subjects with normal renal function. The 25-hydroxyvitamin D (25OHD) concentrations were normal in all subjects (range, 8-43 ng/ml), although institutionalized subjects had a significantly lower mean value [19.2 +/- 2 (+/- SEM) ng/ml; P less than 0.01] compared with ambulatory subjects (25.3 +/- 2 ng/ml). All but one ambulatory subject had 25OHD3 as the major circulating form, whereas 25OHD2 was the major circulating metabolite in one third of the institutionalized subjects. The mean 1,25-dihydroxyvitamin D [1,25-(OH)2D] concentration in both groups was normal, but nine subjects had levels at or below the lower limit of normal despite normal 25OHD concentrations. Separate assay of 1,25-(OH)2D2 and 1,25(OH)2D3 revealed proportional distributions similar to those for 25OHD2 and 25OHD3. To study the effect of age on the intestinal absorption of vitamin D, we compared serum vitamin D2 concentrations after oral administration of 50,000 IU vitamin D2 in both healthy vitamin D-sufficient elderly subjects and young adults. We found no evidence of malabsorption of vitamin D in the elderly subjects. In summary, elderly subjects in New York, whether institutionalized or not, have normal serum 25OHD concentrations. However, while most elderly subjects have normal serum 1,25-(OH)2D levels, a significant proportion fail to produce normal concentrations of 1,25-(OH)2D, possibly due to age-related disturbances in renal synthesis of the hormone.

25-Hydroxyvitamin D 2↗
PubMed1983

Serum levels of 25-hydroxyvitamin D in adults and elderly humans after a prophylactic dose of vitamin D2.

Vitamin D2 was administered orally as a single dose (2 mg) to 19 elderly subjects and 17 young adults. The maximum elevation of serum 25-hydroxyvitamin D was significantly greater in young than in elderly subjects. To evaluate intestinal absorption we also measured serum levels of vitamin D2 5 h after the given dose. A vitamin A absorption test was also performed simultaneously. Small differences between young and old subjects were seen with respect to serum vitamin D2 or vitamin A increments. In both groups the serum level of 25-hydroxyvitamin D was still elevated above initial level 60 days after a dose was given. No side effects, nor any change in serum calcium ion activity were noted during this period. These results speak in favour of the use of intermittent large doses of vitamin D2 as a prophylaxis against vitamin D deficiency in the elderly.

Adult↗
PubMed1984

Differences in the metabolism of vitamin D2 and vitamin D3 by subcellular fractions from rat liver.

The 25-hydroxylation of vitamin D2 and vitamin D3 was studied in the mitochondrial fraction from rat liver and in a reconstituted system containing cytochrome P-450 from rat liver microsomes. The mitochondrial fraction catalyzed the 25-hydroxylation of vitamin D3 at least two times more effectively than the 25-hydroxylation of vitamin D2. Microsomal cytochrome P-450 catalyzed an efficient 25-hydroxylation of vitamin D3, but no 25-hydroxylation of vitamin D2 could be detected. The present results show a difference in the 25-hydroxylation of vitamin D2 and vitamin D3 in rat liver in vitro.

Animals↗
PubMed1984

The isolation and identification of vitamin D2 and vitamin D3 from Medicago sativa (alfalfa plant).

Vitamin D2 and vitamin D3 were isolated from Medicago sativa (alfalfa) grown under field and laboratory conditions and then irradiated with ultraviolet light. The vitamins were identified by ultraviolet absorption, mass spectroscopy, and comparison with synthetic standards on several chromatographic systems. Sun-cured, field-grown alfalfa contained vitamin D2 at a concentration of 48 ng/g (1920 IU/kg) and vitamin D3 at 0.63 ng/g (25 IU/kg). Laboratory-grown alfalfa, artificially irradiated, contained vitamin D2 at a concentration of 80 ng/g and vitamin D3 at 1.0 ng/g. Therefore, the presence of vitamin D2, as well as vitamin D3, has unequivocally been demonstrated in alfalfa plant tissue.

Chemical Phenomena↗
PubMed1987

Effect of vitamin D2 and vitamin D3 on the serum concentrations of 1,25(OH)2D2, and 1,25(OH)2D3 in normal subjects.

Serum concentrations of vitamin D2 and vitamin D3 metabolites were measured in 19 normal subjects before and during treatment with either vitamin D2 or vitamin D3, 4000 IU per day for 8 weeks. Vitamin D2 treatment increased the serum concentration of 1,25(OH)2D2, but a corresponding decrease in 1,25(OH)2D3 resulted in an unchanged serum concentration of total 1,25(OH)2D. During treatment with vitamin D3, the serum concentration of 1,25(OH)2D metabolites was unchanged. We conclude that the production of 1,25(OH)2D is tightly regulated and that 1 alpha-hydroxylase does not discriminate between D2 and D3 metabolites in normal subjects.

Adult↗
PubMed1989

Metabolism of vitamin D2 and vitamin D3 in patients on anticonvulsant therapy.

We examined the effect of short-term treatment with pharmacological doses of vitamin D2 or vitamin D3 on the serum concentration of 1,25(OH)2D metabolites in epileptic patients on chronic anticonvulsant drug therapy. Nine patients were studied before and after treatment with vitamin D2 4000 IU daily for 24 weeks and 10 before and after treatment with vitamin D3 in the same dose. Before treatment the serum concentrations of 1,25(OH)2D and 25(OH)D were significantly lower in epileptics than in normal subjects (P less than 0.01). Vitamin D2 treatment increased the serum concentration of 1,25(OH)2D2, but a corresponding decrease in 1,25(OH)2D3 resulted in an unchanged serum concentration of total 1,25(OH)2D. The serum concentration of 25(OH)D2 and 25(OH)D increased significantly, whereas there was a small decrease in 25(OH)D3. Vitamin D3 treatment did not change the serum concentration of 1,25(OH)2D3 whereas serum 25(OH)D3 increased significantly. The correlation between the serum ratio of 1,25(OH)2D2/1,25(OH)2D3 and 25(OH)D2/25(OH)D3 estimated on vitamin D2-treated epileptic patients and normal subjects was highly significant (P less than 0.01). The data indicate that the serum concentration of 1,25(OH)2D2 and 1,25(OH)2D3 are directly proportional to the amount of their precursors 25(OH)D2 and 25(OH)D3 and that the concentration of total 1,25(OH)2D is tightly regulated.

25-Hydroxyvitamin D 2↗
PubMed1994

Microsomal 25-hydroxylation of vitamin D2 and vitamin D3 in pig liver.

A microsomal cytochrome P-450 catalysing 25-hydroxylation of vitamin D2 was purified from both male and female pigs to apparent homogeneity and a specific cytochrome P-450 content of 13 and 15.4 nmol x mg of protein-1, respectively. The enzyme also catalysed 25-hydroxylation of vitamin D3. The ratio between the 25-hydroxylase activities towards vitamin D2 and D3 was essentially the same in the different purification steps as well as in the apparently homogeneous enzyme preparation. The two enzyme activities showed the same pH optimum and decreased in parallel upon partial denaturation of the enzyme. Cholecalciferol competitively inhibited 25-hydroxylation of vitamin D2 and vice versa. The non-steroidal cytochrome P-450 inhibitor ketoconazole inhibited both enzyme activities and the Ki values were the same. The cytochrome P-450 showed the same apparent M(r), substrate specificity and N-terminal amino acid sequence as the previously purified vitamin D3 25-hydroxylase from pig liver microsomes. A monoclonal antibody raised against the vitamin D3 25-hydroxylase also recognized the vitamin D2 25-hydroxylase. The antibody immunoprecipitated the 25-hydroxylase activity towards both vitamin D2 and D3 in the purified enzyme. Taken together, the results show that the 25-hydroxylation of vitamin D2 and D3 is catalysed by the same microsomal cytochrome P-450 in pig liver microsomes. The properties of this 25-hydroxylase are discussed in relation to present knowledge concerning previously well-characterized vitamin D3 25-hydroxylases that are not able to catalyse 25-hydroxylation of vitamin D2.

Amino Acid Sequence↗
PubMed1985

Different metabolism of vitamin D2 and vitamin D3 in epileptic patients on carbamazepine.

Serum concentrations of vitamin D metabolites were measured in 30 epileptic outpatients on monotherapy with carbamazepine before and during treatment with either vitamin D2 or vitamin D3, 4000 IU per day for 24 weeks. Vitamin D2 treatment increased the serum concentration of 25OHD2, but a corresponding decrease in 25OHD3 resulted in an unchanged serum value of total 25OHD. Vitamin D3 treatment increased the serum concentration of 25OHD3. The resulting serum level of 25OHD was consequently twice the level of that in the D2-treated group. The serum concentrations of the dihydroxy metabolites showed a similar difference between the 2 treatment groups. We conclude that treatment with vitamins D2 and D3 in the same doses produces considerably different serum concentrations of vitamin D metabolites. If the present findings can be extrapolated to normal subjects, it is important to consider more carefully which D-vitamin should be used, both with regard to therapy and supplementation.

Adult↗
PubMed1990

Up-regulation of the intestinal 1,25-dihydroxyvitamin D receptor during hypervitaminosis D: a comparison between vitamin D2 and vitamin D3.

Concentrations of intestinal 1,25-dihydroxyvitamin D receptor were measured in rats receiving pharmacological amounts (25,000 IU/rat daily for 6 days) of either vitamin D2 or vitamin D3. The data showed that both hypervitaminosis D2 and hypervitaminosis D3 resulted in significant up-regulation of intestinal 1,25-dihydroxyvitamin D receptor (fmol/mg protein) relative to controls (409 +/- 24, vitamin D2-treated; 525 +/- 41, vitamin D3-treated; and 249 +/- 19, control). The 1,25-dihydroxyvitamin D receptor enhancement also was accompanied by elevated plasma 25-hydroxyvitamin D and hypercalcemia. These data suggest that increased target-tissue 1,25-dihydroxyvitamin D receptor may play a role in enhancing target-tissue responsiveness and, thus, have a significant role in mediating the toxic effects of hypervitaminosis D.

Animals↗
PubMed1982

Synthesis and biological activity of vitamin D2 3 beta-glucosiduronate and vitamin D2 3 beta-sulfate: role of vitamin D2 conjugates in calcium homeostasis.

To ascertain the physiologic function of vitamin D2 conjugates in calcium homeostasis, we synthesized vitamin D2 3 beta-glucosiduronate and vitamin D2 3 beta-sulfate in pure form and tested their biological activity in vitamin D deficient rats fed a low calcium diet. Vitamin D2 3 beta-glucosiduronate was active in promoting calcium transport in the intestine at a dose of 100 pmol per rat. It increased calcium mobilization from bone and soft tissue at a dose of 1000 pmol per rat. This conjugate was less active than equimolar doses of vitamin D2. These results demonstrate that vitamin D2 3 beta-glucosiduronate can be utilized by the rat as a source of vitamin D. In contrast, vitamin D2 3 beta-sulfate was biologically inert. It failed to increase calcium transport in the duodenum of vitamin D deficient rats except at the highest doses tested (greater than 100,000 pmol/rat). It was similarly ineffective in increasing calcium mobilization from bone and soft tissue. Our results lead us to conclude that vitamin D2 3 beta-glucosiduronate is probably utilized by the rat after hydrolysis to the free sterol; on the contrary, the sulfate is not biologically active except at the highest doses tested.

Animals↗
PubMed1979

Assay for vitamin D2 and vitamin D3 in plasma of dairy cows: changes after massive dosing of vitamin D3.

A sensitive, precise assay for vitamin D in plasma is described. Three to five milliliters of plasma were extracted with methanol:methylene chloride (2:1). The lipid extract was chromatographed on Sephadex LH-20 and then on lipidex-5000 columns. After high pressure liquid chromatography with a reverse phase chromatographic system, vitamin D2 and vitamin D3 were quantitated by ultraviolet absorbance. We used this assay system for monitoring daily changes of vitamin D3 in plasma of two Jersey cows after four intramuscular doses (15 x 10(6) IU) of vitamin D3 administered at weekly intervals. Basal vitamin D in plasma was 3.2 +/- .99 ng/ml with a range of 1.7 to 4.9 ng/ml. Vitamin D3 in plasma remained relatively low (10 to 45 ng/ml) the week after the first vitamin D3 injection. Vitamin D3 was high (130 to 234 ng/ml) after the second, third, and fourth injections. Vitamin D3 decreased steadily to 88 ng/ml by 38 days after the fourth vitamin D3 injection. Phosphorus in plasma increased sharply to a plateau at 9.5 mg/100 ml during the week after the second vitamin D3 injection and returned to normal (4.5 mg/100 ml) at the end of the experiment. Calcium, however, gradually increased to 14.0 mg/100 ml 20 days after the fourth vitamin D3 injection. Both animals remained hypercalcemic (calcium 11.5 mg/100 ml) during the experiment.

Animals↗
PubMed2006

The case against ergocalciferol (vitamin D2) as a vitamin supplement.

Supplemental vitamin D is available in 2 distinct forms: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Pharmacopoeias have officially regarded these 2 forms as equivalent and interchangeable, yet this presumption of equivalence is based on studies of rickets prevention in infants conducted 70 y ago. The emergence of 25-hydroxyvitamin D as a measure of vitamin D status provides an objective, quantitative measure of the biological response to vitamin D administration. As a result, vitamin D3 has proven to be the more potent form of vitamin D in all primate species, including humans. Despite an emerging body of evidence suggesting several plausible explanations for the greater bioefficacy of vitamin D3, the form of vitamin D used in major preparations of prescriptions in North America is vitamin D2. The case that vitamin D2 should no longer be considered equivalent to vitamin D3 is based on differences in their efficacy at raising serum 25-hydroxyvitamin D, diminished binding of vitamin D2 metabolites to vitamin D binding protein in plasma, and a nonphysiologic metabolism and shorter shelf life of vitamin D2. Vitamin D2, or ergocalciferol, should not be regarded as a nutrient suitable for supplementation or fortification.

Biomarkers↗
PubMed1983

Radioimmunoassay of 1,25-dihydroxy vitamin D2: studies on the metabolism of vitamin D2 in man.

A sensitive radioimmunoassay for 1,25-dihydroxy vitamin D2 was developed using a sheep antiserum which preferentially reacts with 1-hydroxylated forms of vitamin D. An improved isolation procedure was also developed using acetonitrile for the initial extraction of serum followed by chromatography on cartridges of C18 silica and high pressure liquid chromatography eluted with a ternary solvent system to separate 1,25-dihydroxy vitamin D2 and 1,25-dihydroxy vitamin D3. 25-hydroxy vitamin D2 and 25-hydroxy vitamin D3 were separated by further reverse phase high pressure liquid chromatography prior to competitive protein binding assay. The limits of detection were 4.3 pmol/1 (2.0 pg/ml) for the 1,25-dihydroxy metabolites and 1.25 nmol/1 (0.5 ng/ml) for both 25-hydroxy vitamin D2 and 25-hydroxy vitamin D3. 25-hydroxy vitamin D2 ranged from 2.0 to 11.3 nmol/1 (0.8-4.5 ng/ml) with a mean of 4.75 nmol/1 (1.9 ng/ml) in thirteen healthy British adults and this accounted for 9.0% of the mean total 25-hydroxy vitamin D. 1,25-dihydroxy vitamin D2 was detected in the sera of only one of these subjects whereas 1,25-dihydroxy vitamin D3 was present in all ranging from 48 to 163 pmol/1 (20-65 pg/ml) with a mean of 100 pmol/1 (42 pg/ml). Both 1,25-dihydroxy vitamin D2 and 1,25-dihydroxy vitamin D3 were detected in the sera of hypoparathyroid patients treated with vitamin D2 but the relationship between 25-hydroxy vitamin D and 1,25-dihydroxy vitamin D was complex. For example, when an excess of 25-hydroxy vitamin D2 was present the serum concentration of 1,25-dihydroxy vitamin D3 was disproportionately high. Conversely, in patients who had previously been treated with vitamin D2 but were receiving only vitamin D3 at the time of study, the major 25-hydroxy metabolite was in the vitamin D3 form and there was a disproportionately high amount of 1,25-dihydroxy vitamin D2. Total 1,25-dihydroxy vitamin D ranged from 110 to 400 pmol/1 (45-165 pg/ml) and was above the upper limit of normal for 1,25-dihydroxy vitamin D3 in half of these hypoparathyroid patients treated with pharmacological doses of vitamin D.

25-Hydroxyvitamin D 2↗
PubMed1987

Synthesis of 25-hydroxy-[26,27-3H]vitamin D2, 1,25-dihydroxy-[26,27-3H]vitamin D2 and their (24R)-epimers.

Synthesis of a C-24-epimeric mixture of 25-hydroxy-[26,27-3H]vitamin D2 and a C-24-epimeric mixture of 1,25-dihydroxy-[26,27-3H]vitamin D2 by the Grignard reaction of the corresponding 25-keto-27-nor-vitamin D2 and 1 alpha-acetoxy-25-keto-27-nor-vitamin D3 with tritiated methyl magnesium bromide is described. Separation of epimers by high-performance liquid chromatography afforded pure radiolabeled vitamins of high specific activity (80 Ci/mmol). The identities and radiochemical purities of 25-hydroxy-[26,27-3H[vitamin D2 and 1,25-dihydroxy-[26,27-3H]vitamin D2 D2 were established by cochromatography with synthetic 25-hydroxyvitamin D2 or 1,25-dihydroxyvitamin D2. Biological activity of 25-hydroxy-[26,27-3H]vitamin D2 was demonstrated by its binding to the rat plasma binding protein for vitamin D compounds, and by its in vitro conversion to 1,25-dihydroxy-[26,27-3H]vitamin D2 by kidney homogenate prepared from vitamin D-deficient chickens. The biological activity of 1,25-dihydroxy-[26,27-3H]vitamin D2 was demonstrated by its binding to the chick intestinal receptor for 1,25-dihydroxyvitamin D3.

25-Hydroxyvitamin D 2↗