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PubMedDate not supplied

[Comparative study of the biological activity and toxic effect of 1alpha-hydroxycholecalciferol and ergocalciferol in rats].

Single administration of 0.25 microgram of sunthetic Ialpha-hydroxycholecalciferol (IalphaOHD3) into nephrectomized rats, maintained at D-avitaminous diet, improved the active transport of calcium ions against the concentration gradient in small intestine of these animals, whereas ergocalciferol was biologically inactive under the same conditions. Administration of IalphaOHD3 during 5 days at a dose 0.025 microgram normalized calcium content in blood serum of rats with D-avitaminosis, Increased doses of IalphaOHD3, administered into intact animals, caused transient hyperphosphatemia, hypercalcemia, calcinosis of internal tissues (kidney heart, aorta) as well as death of some animals. IalphaOHD3 exceeded 400-fold the hypercalcemic and calcinose effects of ergocalciferol. LD50 for IalphaOHD3 was equal to 100 microgram/kg, if it was administered during 5 days per os. Tissue calcinosis was developed after administration of a daily dose 10 microgram/kg, moderate hypercalcemia was caused by a daily dose 1 microgram/kg or 0.25 microgram per an animal; this amount is only 10-fold higher as compared with the physiologic requirement. Ergocalciferol caused hypercalcemia and metastatic calcification only at a dose 4000 microgram/kg. Clinical use of IalphaOHD3 at doses, exceeding the physiologic requirements, has to be prohibited due to high activity of the preparation and to toxicity of its increased doses.

Animals↗
PubMed1976

High-performance liquid chromatographic analysis of vitamins I: quantitation of cholecalciferol or ergocalciferol in presence of photochemical isomers of the provitamin and application to cholecalciferol resins.

A high-performance liquid chromatographic (HPLC) procedure was developed for the quantitative determination of cholecalciferol or ergocalciferol in the presence of the photochemical isomers of the provitamin. Separation is also achieved from various common reaction products encountered in the vitamin synthesis as well as other fat-soluble vitamins. The method was applied to the routine analysis of cholecalciferol resins, and experimental data are set forth. A comparison of the HPLC method to the AOAC biological and chemical procedures shows that the HPLC method most closely approximates the antirachitic activity of a cholecalciferol sample. The specificity, sensitivity, and reproducibility of the method make it applicable to various vitamin samples containing cholecalciferol or ergocalciferol.

Biological Assay↗
PubMed1976

Effects of ergosterol on bone mineralisation in chicks given cholecalciferol or ergocalciferol.

Groups of chicks were given diets containing cholecalciferol or ergocalciferol supplemented with 0, 0-1, 1 or 10 g ergosterol/kg. 2. Ergosterol had no significant effect on growth, on the plasma concentration of calcium or on the content of bone-ash, indicating that it did not impair the absorption of either form of vitamin D. 3. An explanation is given for the apparent disagreement in the published findings on the relative anti-rachitic potencies of ergocalciferol and cholecalciferol in the chick.

Animals↗
PubMed1977

An improved procedure for the isolation of suprasterol2 I and II from a photochemical reaction mixture of ergocalciferol (vitamin D2).

An improved procedure for the isolateion suprasterol2 I and II from a photochemical reaction mixture of ergocalciferol (vitamin D2) and their spectral data are described in this paper. When a solution of ergocalciferol in ethanol was irradiated by UV light from a high-pressure mercury lamp, the reaction mixture gave six spots, including suprasterol2 I and II, on the thin-layer chromatogram, while the peaks corresponding to pyro-D2, isopyro-D2,5,b-trans-D2, suprasterol 2 I and II were observed in the gas chromatogram obtained from a capillary column GLC (Suprasterol2 I and II were main peaks). After purifying the mixture by column chromatography on silica gel containing 12% alumina as an absorbent, two main fractins were isolated. The data of their spectra, TLC and GLC showed that the former fraction was suprasterol2 II while the latter was suprasterol2 I and that the both fractions contained the respective compound only. Both suprasterol2 were crystallized as the 3,5-dinitro-benzoates.

Cyclosteroids↗
PubMedDate not supplied

[Toxic action of ergocalciferol in strontium rickets].

Tests conducted on albino rats of the Wistar line demonstrated that introduction of large doses of ergocalciferol (vitamin D2) to animals kept on a strontium-rich diet exhibiting signs of rickets brings about the development in them of specific manifestations of the D-vitamin activity, viz. rising level of calcium, strontium and inorganic phosphorus in the blood serum, lowering of the alkaline phosphatase activity and a greater degree of the soft tissues calcification.

Animals↗
PubMed1976

Combined assays for vitamins A, D (ergocalciferol), and E in multivitamin preparations with separation by reversed-phase partition chromatography.

A rapid method was developed whereby vitamins A, D (ergocalciferol), and E in multivitamin products are measured in a common assay sample. The method depends on reversed-phase partition chromatography by which the vitamin alcohols are eluted in separate fractions from a column. Vitamins A and E are then determined by their UV absorption, while vitamin D is measured colorimetrically with an antimony trichloride reagent. The column consists of diatomaceous earth impregnated with dimethyl polysiloxane, with n-heptane as the immobile solvent, and 90% methanol followed by 95% methanol as the mobile solvents. Vitamins A and D elute in that order in the 90% methanol, and finally vitamin E elutes in the 95% methanol fraction. The method is widely applicable to various types of multivitamin and vitamin-mineral products including oil-based, water-based, and dry formulations.

Alkalies↗
PubMed1978

High-performance liquid chromatography determination of potential content of vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol) in resins, oils, dry concentrates and multivitamin formulations.

The determination of potential vitamin D concentrations in raw materials and in multivitamin formulations by high-performance liquid chromatography is reported. Simple experimental conditions allow the rapid separation of the vitamins from their respective pro- and pre-vitamins, from their irradiation side-products and from some of their overirradiation products. Vitamin extraction is performed directly from dry concentrates, tablets and capsules, without saponification; all procedures are carried out at room temperature so as to preserve the ratio of vitamin D and pre-vitamin D present in the prepatation. The relative standard deviation is less than 1.5%.

Cholecalciferol↗
PubMedDate not supplied

[Effect of thyroid and adrenal hormones on the course of hypervitaminosis A and D].

Tests staged on normal and hypophysectomized rats demonstrated thyroxin to potentiate the general toxic effect of ergocalciferol, with final death of the animals. At the same time, the blood calcium content in animals receiving thyroxin decreases under the effect of the latter. Hydrocortisone, while producing no effect on the high calcium content in the blood of the animals receiving ergocalciferol, attenuates the general toxic action of the latter. These data point to the possibility of dissociating the general toxic action of ergocalciferol and its influence on the blood calcium level, which disproves the existing notion on the correlation between general toxic action of ergocalciferol and hypercalcemia produced by it. Thyroxin and hydrocortisone do not have any effect on the nature of the action exerted by high doses of vitamin A.

Animals↗
PubMed1979

Determination of vitamin D and its metabolites in plasma from normal and anephric man.

A multiple assay capable of reliably determining vitamins D(2) and D(3) (ergocalciferol and cholecalciferol), 25(OH)D(2) (25-hydroxyvitamin D(2)) and 25(OH)D(3) (25-hydroxyvitamin D(3)), 24,25(OH)(2)D (24,25-dihydroxyvitamin D), 25,26(OH)(2)D (25,26-dihydroxyvitamin D) and 1,25(OH)(2)D (1,25-dihydroxyvitamin D) in a single 3-5ml sample of human plasma was developed. The procedure involves methanol/methylene chloride extraction of plasma lipids followed by separation of the metabolites and purification from interfering contaminants by batch elution chromatography on Sephadex LH-20 and Lipidex 5000 and by h.p.l.c. (high-pressure liquid chromatography). Vitamins D(2) and D(3) and 25(OH)D(2) and 25(OH)D(3) are quantified by h.p.l.c. by using u.v. detection, comparing their peak heights with those of standards. 24,25(OH)(2)D and 25,26(OH)(2)D are measured by competitive protein-binding assay with diluted plasma from vitamin D-deficient rats. 1,25(OH)(2)D is measured by competitive protein-binding assay with diluted cytosol from vitamin D-deficient chick intestine. Values in normal human plasma samples taken in February are: vitamin D 3.5+/-2.5ng/ml; 25(OH)D 31.6+/-9.3ng/ml; 24,25(OH)(2)D 3.5+/-1.4ng/ml; 25,26(OH)(2)D 0.7+/-0.5ng/ml; 1,25(OH)(2)D 31+/-9pg/ml (means+/-s.d.). Values in two normal human plasma samples taken in February after 1 week of high sun exposure are: vitamin D 27.1+/-7.9ng/ml; 25(OH)D 56.8+/-4.2ng/ml; 24,25(OH)(2)D 4.3+/-1.6ng/ml; 25,26(OH)(2)D 0.5+/-0.2ng/ml. Values in anephric-human plasma are: vitamin D 2.7+/-0.8ng/ml; 25(OH)D 36.4+/-16.5ng/ml; 24,25(OH)(2)D 1.9+/-1.3ng/ml; 25,26(OH)(2)D 0.6+/-0.3ng/ml; 1,25(OH)(2)D was undetectable.

Animals↗
PubMed1977

Components of 25-hydroxyvitamin D in serum of young children in upper midwestern United States.

The relative importance of cholecalciferof (vitamin D3) and ergocalciferol (vitamin D2) in maintaining the vitamin D level in children (1/2 to 6 years old) living in the upper midwestern United States was determined by measurement of total 25-hydroxyvitamin D (25-OH-D), its components, and other indices of calcium homeostasis in serum. In 38 normal children, mean (range) serum total 25-OH-D was 32.8 (less than 5 to 53) ng/ml; in 25 of the 28 sera partitioned, the major component was 25-OH-D3. Significant seasonal variation in serum 25-OH-D3 (mean, range: 35.2, 17 to 51 ng/ml in summer and 15.9, less than 5 to 32 ng/ml in winter) was not accompanied by changes in mean serum 25-OH-D2, calcium, phosphorus, or alkaline phosphatase values. However, individual serum total 25-OH-D values correlated with serum phosphorus values (r = 0.37; P less than 0.05). The proportion of the total represented by 25-OH-D3 varied widely, with a a mean of 83% in summer and 67% in winter. Sources of D3, which include both dermal synthesis and intestinal absorption of D3 added to milk, appear to be more important than sources of D2 in maintaining vitamin D nutrition of young children throughout the year. However, sources of D2 offset the decrease in total 25-OH-D in winter months.

Alkaline Phosphatase↗
PubMed1979

The relevance of 25-hydroxycalciferol measurements in the treatment of hypoparathyroidism.

In twenty-one patients with chronic hypoparathyroidism a close correlation was observed between the prescribed dose of ergocalciferol and mean serum 25-hydroxycalciferol levels. In the 75 serum specimens examined, a significant correlation was found between 25-hydroxycalciferol levels and calcium concentrations. The measurement of serum 25-hydroxycalciferol levels is of potential clinical value in the prediction of hyper- or hypocalcaemic episodes and in monitoring patient compliance.

Adolescent↗
PubMed1978

A familial syndrome of decrease in sensitivity to 1,25-dihydroxyvitamin D.

Typical features of hereditary vitamin D-dependent (pseudovitamin D-deficient) rickets were observed beginning at ages 20 and 5 months in a brother and sister. Both had calcium malabsorption correctable with high doses of 25-hydroxyvitamin D. During periods of hypocalcemia they both manifested secondary hyperparathyroidism with hypophosphatemia and high serum concentrations of endogenously produced 1,25-dihydroxyvitamin D. In each, normalization of serum calcium concentration and resolution of osteomalacia were obtained with continuous administration of high doses of ergocalciferol or high doses of 1,25-dihydroxycholecalciferol. Chemical features of vitamin D deficiency were corrected in the presence of high circulating concentrations of 1,25-dihydroxyvitamin D2, produced endogenously, or of 1,25-dihydroxyvitamin D3, administered by mouth. Serum concentrations of 25-hydroxyvitamin D2, 25-hydroxyvitamin D3, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D were normal in five first degree relatives. We conclude that in these five first degree relatives. We conclude that in these siblings, rickets and osteomalacia resulted from a hereditary decreased sensitivity to 1,25-dihydroxyvitamin D at the intestine and perhaps other vitamin D target tissues.

Absorption↗
PubMedDate not supplied

[Possible role of free radicals in the transformations and mechanism of physiological action of vitamin D].

Deficiency of vitamine D is accompanied with a decrease of ESR signal intensity from g = 2.003, as well as of the signals with g = 1.94 and gav. = 2.25 in the liver and kidneys of young rats. Injection of 2.5 g ergocalciferole (vitamine D2) to these animals results in a complete or partial normalization of the intensity of these signals during 6--16 hrs and an increase of the ESR signal intensity from g = 2.003 in small intestine mucosa.

Animals↗
PubMed1977

High pressure liquid chromatographic separation and identification of vitamins D2 and D3 in the presence of fat-soluble vitamins in dosage forms.

A simple and rapid qualitative method is described for determining the presence of vitamin D2 (ergocalciferol) and/or vitamin D3 (cholecalciferol) in various preparations by reverse phase high pressure liquid chromatography (HPLC). When both D2 and D3 are present, this method effectively separates and identifies each vitamin D form by its respective retention time. A significant difference between vitamins D2 and D3 exists in their antirachitic activity in poultry. Preparations can be tested rapidly by this method to ascertain that the correct D vitamin form has been added. Fat-soluble vitamins such as vitamins A, E, K1, and K3 do not interfere. Vitamins D2 and D3 were separated at the baseline in model preparations. As little as 2 ng each of vitamin D2 and vitamin D3 can be separated and identified.

Cholecalciferol↗
PubMed1979

Naturally occurring vitamin D3 in fish products analysed by HPLC, using vitamin D2 as an international standard.

A chemical method for the analysis of naturally occurring vitamin D is proposed. The unsaponifiable matter of oils and tissues is prepared, cholesterol is partly removed by double precipitation at low temperature in methanol. The vitamin D fraction is collected on an adsorption column by high performance liquid chromatography. The fraction is further purified and the vitamins D2 and D3 are separated on a partition column (reverse phase) by HPLC. Recovery was 89 to 93%, standard deviation 3%. The only vitamin D analogue found in fish oils, livers and fillets, was cholecalciferol (D3). Hence, ergocalciferol (D2) could be used as an internal standard. The provitamins ergosterol and 7-dehydrocholesterol, as well as the previtamins, were separated from the vitamin D-fraction on the adsorption column. Results in the range 0.050 to 134 microgram D3 per gram (2 to 5360 I.U. per gram) are given. One cod liver oil was analysed in a rat bioassay, giving supporting results.

Adsorption↗
PubMedDate not supplied

[Comparative study of the hemolytic action of group D vitamins].

Hemolytic effects of the vitamins of the D group (ergocalciferol - D2, cholecalciferol - D3, and 1 alpha-hydroxycholecalciferol - 1 alpha-OH-D3) were compared using rat erythrocytes. The latent period of hemolysis, caused by 1 alpha-OH-D3 was approximately 3-fold shorter as compared with the hemolysis caused by D2 or D3. Apparent values for energy of activation of hemolysis, estimated at 30-45 degrees, constituted for D2 - 23.2 kcal/mol, D3 - 25.3 kcal/mol, 1 alpha-OH-D3 - 13.1 kcal/mol. Despite the higher hemolytic activity, the rate of 1 alpha-ON-D3 autooxidation was distinctly lower than that of D3.

Animals↗
PubMedDate not supplied

[Functional activity of mitochondria and intensity of nucleic acid and protein synthesis in rat liver and small intestine mucosa with different supplies of vitamin D].

Decrease in total content of mitochondrial protein in mucosa of small intestine, an alteration of distribution of the protein between the fractions of mitochondria, distinct decrease in the respiratory activity of mitochondria and in the activity of succinate- and NADH-dehydrogenases were observed in rats deficient in vitamin D. Deficiency in vitamin D was accompanied by decreased incorporation of labelled precursors into total, nuclear and mitochondrial DNA and RNA by 20-50% and into mitochondrial proteins--by 50% in mucosa of small intestine; these patterns were unaltered in liver tissue. Administration of ergocalciferol (at a dose 1000 IU) into rats normalized the impairments studied, whose alteration correlated with the increase of calcium concentration in blood serum.

Animals↗