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Burgos-Trinidad M, Brown AJ, DeLuca HF. Solubilization and reconstitution of chick renal mitochondrial 25-hydroxyvitamin D3 24-hydroxylase. Biochemistry 1986; 25:2692-6. [PMID: 3718974 DOI: 10.1021/bi00357a061] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Chick kidney mitochondrial 25-hydroxyvitamin D3 24-hydroxylase has been solubilized with sodium cholate and reconstituted with NADPH, beef adrenal ferredoxin, and beef adrenal ferredoxin reductase, each component being essential for maximal 24-hydroxylase activity. The product 24(R),25-dihydroxyvitamin D3 was identified by cochromatography with synthetic compound on straight-phase and reversed-phase high-performance liquid chromatography and by periodate oxidation. The enzyme has an apparent Km for 25-hydroxyvitamin D3 of 0.67 microM. At 1 microM 25-hydroxyvitamin D3, 24,25-dihydroxyvitamin D3 production is linear with time for up to 15 min and with protein concentrations of up to 2 mg/mL. The antioxidant diphenyl-p-phenylenediamine (1.3 X 10(-4) M) has no effect on this reaction. Reconstituted 24-hydroxylase activity is enhanced by the addition of NaCl and KCl up to 100 mM, with higher concentrations having an inhibitory effect. 1 alpha-Hydroxylase is not present in this preparation from vitamin D replete chicks. The similarities of this reconstituted system to the 25-hydroxyvitamin D3 1 alpha-hydroxylase and the adrenal systems suggest that the 25-hydroxyvitamin D3 24-hydroxylase is also a cytochrome P-450 type mixed-function oxidase.
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102
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Hines TG, Horst RL, Littledike ET, Beitz DC, Jacobson NL. Vitamin D3 and D3 metabolites in young goats fed varying amounts of calcium and vitamin D3. J Dairy Sci 1986; 69:385-91. [PMID: 3009577 DOI: 10.3168/jds.s0022-0302(86)80416-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Twenty-four male goats, 2 to 4 wk of age, were allotted to four dietary treatments in a 2 X 2 factorial design and, for 20 wk, were fed a milk diet at 12.5% body weight. Treatments varied in amounts of supplemental calcium and vitamin D3. Daily allowances per kilogram body weight were: 9.4 IU vitamin D3 (basal), 9.4 IU vitamin D3 plus 406 mg calcium carbonate (basal plus Ca), 940 IU vitamin D3 (basal plus D3), and 940 IU vitamin D3 plus 406 mg calcium carbonate (basal plus Ca plus D3). At the end of wk 7, a corn supplement was added to all diets at 1% body weight daily. Addition of vitamin D3 to the diet resulted in a dramatic increase in plasma concentrations of vitamin D3. Goats in the basal plus D3 and basal plus Ca plus D3 groups had nearly 100 X greater concentrations of vitamin D3 than goats in the basal and basal plus Ca groups. When greater amounts of vitamin D3 were fed, dietary calcium interacted to decrease plasma vitamin D3 concentrations. Plasma concentrations of 25-hydroxyvitamin D3 were unaffected by additional dietary calcium but were increased by dietary vitamin D3, increasing sixfold to seven-fold in the basal plus D3 and basal plus Ca plus D3 groups. Supplemental calcium resulted in decreased plasma 1,25-dihydroxyvitamin D3. No signs of vitamin D toxicity were noted. The physiological responses reported implicate the goat as a potential animal model for vitamin D research in dairy cattle.
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103
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Abstract
The vitamin D endocrine system plays an important role in the maintenance of normal calcium homeostasis. Abnormalities of this system occur in many conditions, such as rickets, osteomalacia, hypoparathyroidism, and hyperparathyroidism. The diagnosis and treatment of these disorders will be facilitated if the clinician understands the general mechanisms by which defects in vitamin D metabolism and action occur. We review this information and discuss the use and limitations of vitamin D metabolite assays for diagnosis of clinical disorders of mineral metabolism.
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104
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Brown AJ, DeLuca HF. Production of 10-oxo-19-nor-25-hydroxyvitamin D3 by solubilized kidney mitochondria from chick and rat. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(17)38693-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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105
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Delvin EE, Dussault M. Kinetics of kidney mitochondrial 25-hydroxycholecalciferol-1 alpha-hydroxylase in vitamin D-repleted weanling guinea pigs. Arch Biochem Biophys 1985; 240:337-44. [PMID: 4015107 DOI: 10.1016/0003-9861(85)90039-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Kinetics of vitamin D-repleted guinea pig kidney mitochondrial 25-hydroxycholecalciferol-1 alpha-hydroxylase were studied. Omission of malate, source of mitochondrial reducing equivalents, abolished the 1 alpha-hydroxylase activity as well as the degradation of 1 alpha, 25-dihydroxycholecalciferol [1,25(OH)2D3], indicating that both functions shared elements of a common pathway. Preincubation of the mitochondrial preparation in presence of 10 nM 1,25(OH)2D3 for 15 min protected the labeled 1,25(OH)2D3 from degradation. Under these conditions an apparent Km of 605 nM and a Vmax of 40 pmol/30 min/mg mitochondrial protein were observed. These data show that this particular mammalian model may be used to study the modulation of mammalian 1 alpha-hydroxylase activity.
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106
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Sicinski RR, Tanaka Y, Schnoes HK, DeLuca HF. Synthesis of 1α,25-dihydroxyvitamin D2, its 24 epimer and related isomers, and their binding affinity for the 1,25-dihydroxyvitamin D3 receptor. Bioorg Chem 1985. [DOI: 10.1016/0045-2068(85)90018-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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107
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108
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Schneider KM, Parkinson GB, Houston JC, Leaver DD. 1,25 dihydroxyvitamin D3 increases plasma magnesium and calcium in sheep fed liquid diets low in calcium and magnesium. Aust Vet J 1985; 62:82-5. [PMID: 3839393 DOI: 10.1111/j.1751-0813.1985.tb14144.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Sheep given a liquid diet low in calcium and magnesium by infusion directly into the abomasum developed concurrent hypocalcaemia and hypomagnesaemia, with plasma concentrations of calcium and magnesium decreasing to 2.0 and 0.4 mmol/l respectively. Treatment of these hypomagnesaemic sheep with 1,25 dihydroxyvitamin D3 (1,25(OH)2 D3) increased the plasma calcium, magnesium and phosphorus concentrations with plasma calcium increasing to 2.5 mmol/l and plasma magnesium to 0.6 mmol/l. Plasma magnesium increased despite a small but significant increase in the daily excretion of magnesium in the urine, and the amount of magnesium derived from either bone and/or intestine must have been greater than the amount lost in the urine. Since in other experiments we have demonstrated that plasma calcium remains within the normal range when a liquid diet adequate in magnesium but low in calcium is infused, these results imply that either synthesis of and/or end organ response to 1,25(OH2) D3 is impaired in magnesium deficient sheep.
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109
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[Vitamin D sterol in human milk, cow's milk and baby food]. ZEITSCHRIFT FUR ERNAHRUNGSWISSENSCHAFT 1985; 24:44-53. [PMID: 2988219 DOI: 10.1007/bf02023894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A review is given of the results of vitamin D determinations in human and cow's milk using physico-chemical methods. Thereby only parent vitamin D is determined. Further, the results obtained with protein-binding assays are discussed in detail. With the aid of these newer methods the concentrations of hydroxylated vitamin D derivatives can also be measured. A comparison of the concentration of these vitamin D metabolites in human milk and infant formulas based upon cow's milk suggests that the higher anti-rachitic activity of human milk is connected with its higher concentration of 25-hydroxy-vitamin D.
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110
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Gascon-Barré M, Elbaz H, Therrien-Ferland D. Sequestration and microsomal C-25 hydroxylation of [3H]-vitamin D3 by the rat liver. Metabolism 1985; 34:244-50. [PMID: 2983177 DOI: 10.1016/0026-0495(85)90007-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A study of the vitamin D3 (D3) 25-hydroxylase was undertaken in an in vivo-in vitro model. [3H]-D3 (0.7, 1.0, 10, or 100 nmol/100 g of body weight) was injected into the portal vein and the liver was excised 18 seconds later. The liver homogenate was then submitted to differential centrifugation and the amount of [3H]-D3 incorporated in the subcellular fractions was evaluated. The microsomal fraction was also incubated in vitro and the appearance of [3H]-25-hydroxyvitamin D3 [25(OH)D3] was determined by high performance liquid chromatography (HPLC). Results showed that the fractional liver [3H]-D3 uptake varied between 37 percent and 48 percent of the dose injected. The intracellular distribution of [3H]-D3 showed that most of the vitamin was incorporated into the microsomal fraction (45% to 50% of the intracellular [3H]-D3) except at the highest dose of [3H]-D3 where the cytosolic fraction contained the highest amount (56.4%) of the incorporated vitamin. Mathematical analysis of the intracellular [3H]-D3 distribution showed that the microsomal fraction was the only subcellular fraction that was found to incorporate [3H]-D3 in relation to the total liver uptake of the vitamin. The apparent Michaelis-Menten kinetics of the [3H]-D3-25-hydroxylase showed that with substrate concentration of up to 88.5 nM, the apparent Km and Vmax were 28.2 nM and 25.8 fentomoles (fmol) X min-1 X mg microsomal pro-1, respectively, but the reaction lost considerable efficiency with higher substrate concentrations. With the in vivo-in vitro model used, the cytosolic fraction was not essential for the optimal C-25 hydroxylation of D3. These results show that the endoplasmic reticulum of rat hepatocytes possess a high capacity for D3 incorporation.(ABSTRACT TRUNCATED AT 250 WORDS)
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Abstract
It is now accepted that vitamin D is an integral part of a complex endocrine system, one with far-reaching implications in mineral metabolism. Reviews of the sources, functions and metabolism of vitamin D, as currently understood, are presented as a prelude to discussions of the role of vitamin D in calcium and phosphorous homeostatis and possible specific roles for vitamin D in mineralized tissues. Data describing a possible regulatory function for vitamin D in bone and bone protein metabolism are presented. Some of the controversy which presently exists regarding the biochemical mechanism of the action of this vitamin is discussed. Finally, the possible relationship of vitamin D and disorders of skeletal tissues is described.
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112
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Ishizuka S, Takeshita T, Norman AW. Naturally occurring 24,25-dihydroxyvitamin D3 is a mixture of both C-24R and C-24S epimers. Arch Biochem Biophys 1984; 234:97-104. [PMID: 6091567 DOI: 10.1016/0003-9861(84)90328-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Tritium-labeled 24,25-dihydroxyvitamin D3 was prepared both in vitro, by using chick kidney homogenates, and in vivo in rats from [26,27-methyl-3H]25-hydroxyvitamin D3. These compounds were mixed with synthetic 24(R),25- and 24(S),25-dihydroxyvitamin D3, converted to the corresponding trimethylsilyl ether derivatives, and analyzed by a high-pressure liquid chromatography procedure that separates the derivatized isomers. The tritium-labeled 24,25-dihydroxyvitamin D3 derivatives were found to be a mixture of both the 24(R) and 24(S) epimers; the ratio was found to be 96.4:3.6 in chick kidney homogenates and 96.8:3.2 in the serum of rats under physiological conditions. In addition, nonradioactive 24,25-dihydroxyvitamin D3 isolated from the serum of rats given large doses of vitamin D3 was shown to be an 89.5:10.5 mixture of the 24(R) and 24(S) isomers. When 25-hydroxy-24-oxo-vitamin D3 was utilized as a substrate, it was found to be more selectively reduced to 24(S),25-dihydroxyvitamin D3 than 24(R),25-dihydroxyvitamin D3 by the renal enzyme. The 24(S),25-dihydroxyvitamin D3 has been identified by ultraviolet absorption spectrophotometry, cochromatography with an authentic standard, and mass spectrometry. The reduced metabolites of 25-hydroxy-24-oxo-vitamin D3 were a 1:50 mixture of the 24(R) and 24(S) epimers. There are two known metabolic pathways leading to 24,25-dihydroxyvitamin D3 from 25-hydroxyvitamin D3; one is 24(R)-hydroxylation of 25-hydroxyvitamin D3 and the other is reduction of 25-hydroxy-24-oxo-vitamin D3. In contrast, 24(S),25-dihydroxyvitamin D3 is produced only by reduction of 25-hydroxy-24-oxo-vitamin D3 in the kidney. Therefore, naturally occurring 24,25-dihydroxyvitamin D3 is a mixture of the 24(R) and 24(S) isomers, and not just the 24(R) isomer as reported previously.
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113
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Ron M, Levitz M, Chuba J, Dancis J. Transfer of 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3 across the perfused human placenta. Am J Obstet Gynecol 1984; 148:370-4. [PMID: 6546472 DOI: 10.1016/0002-9378(84)90709-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The rates of placental transfer of 25-hydroxyvitamin D3 [25-(OH)D3] and 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] were determined in an in vitro perfusion system. Antipyrine was included in each perfusion, and the data are expressed as clearance index, the ratio of hydroxyvitamin D3 to antipyrine clearance. In most experiments, serum, 0.2%, was added to the perfusates as a source of vitamin D3-binding protein. Binding as measured by dextran-coated charcoal assay for 25-(OH)D3 was over 90%, for 1,25-(OH)2D3, only 25% to 50%. The clearance index from the maternal to fetal circulation averaged 0.02 and 0.26 for 25-(OH)D3 and 1,25-(OH)2D3, respectively. When vitamin D3-binding protein was omitted from the perfusate, the clearance indices of 25-(OH)D3 were 0.12 and 0.46 in two experiments. Binding to vitamin D3-binding protein is a major determining factor for the transfer rates of 25-(OH)D3 and 1,25-(OH)2D3.
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114
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Koyama T, Makita T, Enomoto M. Parathyroid morphology in rats after administration of active vitamin D3. ACTA PATHOLOGICA JAPONICA 1984; 34:313-24. [PMID: 6741546 DOI: 10.1111/j.1440-1827.1984.tb07559.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The morphology of the parathyroid gland was examined in rats treated for one month with an active vitamin D3, 1 alpha-hydroxyvitamin D3. On continuous administration of 12.5 micrograms/kg/day of 1 alpha-hydroxyvitamin D3, the first histological change of the parathyroid gland, seen on day 10, was atrophy of the chief cells with marked accumulation of prosecretory granules. Replacement of the parenchyma by small or large cysts was evident on days 20 and 30. The remaining portion of the parathyroid parenchyma showed various histological changes: widened intercellular spaces intermingled with many cytoplasmic processes, shrinkage of the cytoplasm of the chief cells, and the presence of a few ghost cells in cysts. The appearance of cysts may be caused by suppression of parathyroid hormone secretion and is a characteristic lesion in hypervitaminosis in rats induced by treatment with active vitamin D3.
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115
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Vitamin D3 (Cholecalciferol). ACTA ACUST UNITED AC 1984. [DOI: 10.1016/s0099-5428(08)60205-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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116
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Abstract
Four possible diastereoisomers of 23,25,26-trihydroxyvitamin D3 were synthesized and compared with the natural metabolite. The 4 synthetic diastereoisomers could be separated into 4 peaks by high-performance liquid chromatography. The natural 23,25,26-trihydroxyvitamin D3 comigrated with 23(S),25(R),26-trihydroxyvitamin D3. This result unequivocally demonstrates that the stereochemistry of the natural 23,25,26-trihydroxyvitamin D3 has the 23(S) and 25(R) configuration.
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117
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Keck E, Durdel R, West T, Krück F, Meier W, Hennes U, Krüskemper HL, Schweikert HU. Metabolism of 25-hydroxycholecalciferol by human bone. J Endocrinol Invest 1983; 6:211-6. [PMID: 6619529 DOI: 10.1007/bf03350610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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118
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Haddad JG, Aden DP, Kowalski MA. Characterization of the human plasma binding protein for vitamin D and its metabolites synthesized by the human hepatoma-derived cell line, Hep 3B. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)32300-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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119
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Formation of fatty acid esterified vitamin D3 in rat skin by exposure to ultraviolet radiation. J Lipid Res 1983. [DOI: 10.1016/s0022-2275(20)37984-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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120
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Mineral Needs of the Fetus. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/b978-0-12-153205-5.50013-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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121
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Ichikawa Y, Hiwatashi A, Nishii Y. Tissue and subcellular distributions of cholecalciferol 25-hydroxylase: cytochrome P-450D25-linked monooxygenase system. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1983; 75:479-88. [PMID: 6884003 DOI: 10.1016/0305-0491(83)90362-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cholecalciferol (vitamin D3) 25-hydroxylase activity and its tissue and subcellular distributions were studied using rabbit, rat, bovine, chick, duck, guinea-pig and yellowtail. Vitamin D3 25-hydroxylase was found not only rabbit and bovine livers, kidneys and intestines, but also in lungs, pituitary glands, adrenocortices, ovaries, adipose tissues, blood vessels, brains and testes. Subcellular fractions of rabbit livers were examined for the presence of this activity and it was detected in the nuclear membranes, smooth and rough endoplasmic reticula, Golgi membranes and mitochondrial membranes. The activity in microsomes was induced by sodium phenobarbital, but not by beta-naphthoflavone and 3-methylcholanthrene, and was inhibited by isocyanide and metyrapone as inhibitor of cytochrome P-450.
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122
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Isolation and identification of 25-hydroxyvitamin D3-26,23-peroxylactone. A novel in vivo metabolite of vitamin D3. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)33336-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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123
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124
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Ishizuka S, Ishimoto S, Norman AW. Isolation, identification, and biological activity of 23,25,26-trihydroxyvitamin D3, an in vitro and in vivo metabolite of vitamin D3. Arch Biochem Biophys 1982; 217:264-72. [PMID: 7125670 DOI: 10.1016/0003-9861(82)90502-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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125
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126
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Takada K, Takashima A, Shimoi Y. A study of the photobiogenesis of cholecalciferol in vivo and the constraint on its 25-hydroxylation in rat. JOURNAL OF STEROID BIOCHEMISTRY 1981; 14:1361-7. [PMID: 6276613 DOI: 10.1016/0022-4731(81)90343-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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127
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128
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Kumar R, Nagubandi S, Jardine I, Londowski J, Bollman S. The isolation and identification of 5,6-trans-25-hydroxyvitamin D3 from the plasma of rats dosed with vitamin D3. Evidence for a novel mechanism in the metabolism of vitamin D3. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)68771-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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129
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130
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Abstract
The term vitamin D is generally used to describe a number of chemically related compounds with common antirachitic properties, but which have differences in the rapidity of their action, the way they are produced in the body, and the conditions under which their results are optimal. Ergocalciferol, cholecalciferol, 25-hydroxycholecalciferol (calcifediol), dihydrotachysterol, 1 alpha-hydroxycholecalciferol (alfacalcidol), and 1,25-dihydroxycholecalciferol (calcitriol) are currently the most commonly used vitamin D metabolites. In man, cholecalciferol produced on the skin and the fraction obtained from the diet in the gastrointestinal tract are converted in the liver to 25-hydroxycholecalciferol and then in the kidney to 1,25-dihydroxycholecalciferol. The demonstration of these metabolic pathways has helped to elucidate the aetiology of such conditions a hepatobiliary osteodystrophy, drug-induced anticonvulsant osteomalacia, the hypocalcaemia of hypoparathyroidism and above all azotaemic osteodystrophy. In the therapy of azotaemic osteodystrophy, the period of 'vitamin D resistance' when large doses of vitamin D2 and D3 had to be used is now over, and these patients can be efficiently and successfully treated with almost physiological doses of 1 alpha-hydroxycholecalciferol and 1,25-dihydroxycholecalciferol. Attention to diet, calcium supplements and oral phosphate binders are also important. During repetitive haemodialysis, the above principles still hold true, but in some of these patients an osteomalacic syndrome resistant to 1,25-dihydroxycholecalciferol has been recognised. These patients readily become hypercalcaemic when given 1,25-dihydroxycholecalciferol and their fractures and osteomalacia do not improve. Aluminium intoxication, possibly related to the use of impure dialysis fluid, is currently thought to be the most likely explanation of this dialysis osteomalacic syndrome.
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131
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Takasaki Y, Suda T, Yamada S, Takayama H, Nishii Y. Isolation, identification, and biological activity of 25-hydroxy-24-oxovitamin D3: a new metabolite of vitamin D3 generated by in vitro incubations with kidney homogenates. Biochemistry 1981; 20:1681-6. [PMID: 7225351 DOI: 10.1021/bi00509a042] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A metabolite of 25-hydroxyvitamin D3 has been isolated in pure form from incubation mixtures containing kidney homogenates of chicks given large doses of vitamin D3. The isolation involved methanol--chloroform extraction and six steps of column chromatography. The metabolite was identified as 25-hydroxy-24-oxovitamin D3 by means of ultraviolet absorption spectrometry, mass spectrometry, infrared spectrometry, nuclear magnetic resonance spectrometry, and specific chemical reactions. Use of a sensitive in situ technique revealed that 25-hydroxy-24-oxovitamin D3 enhances intestinal calcium transport in rats approximately as effectively as 24,25-dihydroxyvitamin D3 does. In contrast, 25-hydroxy-24-oxovitamin D3 appeared to be less active than 24,25-dihydroxyvitamin D3 in chicks 24 h after intravenous injection.
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132
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Davis WL, Jones RG. Calcium lysosomes in rachitic and vitamin D3 replete chick duodenal absorptive cells. Tissue Cell 1981; 13:381-91. [PMID: 6274055 DOI: 10.1016/0040-8166(81)90012-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Calcium-containing lysomes were described in a previous communication in this series (Davis et al., 1979). Their potential role in intestinal calcium uptake and transcellular transports was hypothesized. To further this notion, the effects of a rachitogenic diet and vitamin D3 repletion were investigated. Intestinal absorptive cells from chicks maintained on a vitamin D deficient diet were characterized by decreased numbers of supranuclear calcium lysosomes. In contrast, intestinal cells from chicks given vitamin D3 (cholecalciferol) subsequent to the rachitogenic diet showed numerous large compound supranuclear calcium lysosomes. Since other steroid hormones are known to effect lysosomes, it is tempting to speculate that vitamin D, itself a steroid hormone, may activate lysosomes which themselves might be involved in calcium homeostatic mechanisms.
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133
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Tanaka Y, DeLuca HF. Measurement of chick kidney 25-hydroxyvitamin D3-1 alpha-hydroxylase without use of radioactive substrate. Anal Biochem 1981; 110:102-7. [PMID: 7193984 DOI: 10.1016/0003-2697(81)90118-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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134
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Seamark DA, Trafford DJ, Makin HL. The estimation of vitamin D and its metabolites in human plasma. JOURNAL OF STEROID BIOCHEMISTRY 1981; 14:111-23. [PMID: 7009987 DOI: 10.1016/0022-4731(81)90200-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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135
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Yeh JK, Aloia JF. The relationship of growth hormone to 1,25-dihydroxyvitamin D3 in intestinal calcium transport. METABOLIC BONE DISEASE & RELATED RESEARCH 1981; 3:47-9. [PMID: 6894959 DOI: 10.1016/s0221-8747(81)80023-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The effects of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and bovine growth hormone (bGH) on intestinal calcium transport have been assessed in vitamin D deficient rats. Calcium transport did not increase after 7 days bGH treatment. A single dose of 1,25(OH)2D3 significantly increased calcium transport in the hypophysectomized (Hx) rats treated with bGH but not in the Hx rats who did not receive bGH, unless the dosage of 2,25(OH)2D3 was increased to 500 p moles. Even though calcium transport in the Hx rats was stimulated by the high dose of 1,25(OH)2D3, this response was less in the Hx than in bGh treated group. These results suggest that growth hormone status may be important in the expression of 1,25-(OH)2D3 action on intestinal calcium transport.
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136
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Stern PH. A monolog on analogs: in vitro effects of vitamin D metabolites and consideration of the mineralization question. Calcif Tissue Int 1981; 33:1-4. [PMID: 6780151 DOI: 10.1007/bf02409404] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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137
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Abstract
Vitamin D, which is normally produced in the skin under ultraviolet irradiation, is the building block for a new endocrine system that involves hydroxylation on the 25-position in the liver followed by 1 alpha-hydroxylation in the kidney to produce the vitamin D hormone, 1 alpha, 25-(OH)2D3. This vitamin D hormone functions in the intestine, bone, and kidney to stimulate transport of calcium and phosphorus into the extracellular fluid compartment upon demand. The production of the vitamin D hormone is tightly feedback regulated directly or indirectly by calcium and phosphorus levels of the plasma. The vitamin D endocrine system is an important one in the regulation of calcium and phosphorus metabolism but is not solely responsible for the calcium and phosphorus transfer reactions occurring during reproduction. The vitamin D hormone functions in the target organs by a nuclear-mediated receptor-based mechanism probably involving the biogenesis of calcium and phosphorus transfer proteins. New target sites of 1,25-(OH)2D3 action in several tissues are suggested by this nuclear localization in those cells. Study of the vitamin D endocrine system has provided a new understanding of metabolic bone diseases and has provided new forms of vitamin D for their treatment. Thus a basic investigation of the regulation of calcium and phosphorus metabolism has rewarded medicine and science with new therapeutic approaches to disease problems.
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138
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Intestinal membrane calcium-binding protein. Vitamin D-dependent membrane component of the intestinal calcium transport mechanism. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)70383-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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139
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Kelly WH, Mirahmadi MK, Simon JH, Gorman JT. Radiographic changes of the jawbones in end stage renal disease. ORAL SURGERY, ORAL MEDICINE, AND ORAL PATHOLOGY 1980; 50:372-81. [PMID: 6935588 DOI: 10.1016/0030-4220(80)90423-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Thirty-eight patients with a history of end stage renal disease (ESRD) were evaluated with panoramic and periapical radiographs for changes in lamina dura, trabecular pattern, radiographic density, and pulp chamber size, as well as the presence of radiolucent lesions not associated with the roots of teeth. Partial or complete loss of lamina dura, delicate of absent trabecular patterns, and an overall granular or chalky white appearance associated with an increase in radiographic density were the most common alterations. These tended to occur together and were most easily observed in the lower molar area superior to the mandibular canal. Radiolucent lesions not associated with the roots of teeth, expansion of alveolar ridges, and radiographic loss of the cortical borders of the maxillary sinus, nasal floor, and mandibular canal were less common but were occasionally noted. Multiple correlation coefficients between radiographic changes and selected biomedical patient data were obtained by computer analysis, and their significance discussed. The pathogenesis of end stage renal disease was also reviewed.
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140
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Ohnuma N, Bannai K, Yamaguchi H, Hashimoto Y, Norman AW. Isolation of a new metabolite of vitamin D produced in vivo, 1 alpha,25-dihydroxyvitamin D3-26,23-lactone. Arch Biochem Biophys 1980; 204:387-91. [PMID: 6252850 DOI: 10.1016/0003-9861(80)90047-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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141
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Yoon PS, Deluca HF. Resolution and reconstitution of soluble components of rat liver microsomal vitamin D3-25-hydroxylase. Arch Biochem Biophys 1980; 203:529-41. [PMID: 6779710 DOI: 10.1016/0003-9861(80)90210-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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142
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Kálmán J, Gömöri A, Juhász J, Szücs J. Serum 25-hydroxycalciferol concentrations in normal subjects and in haemodialysed patients with chronic renal failure. Int Urol Nephrol 1980; 12:257-62. [PMID: 7251291 DOI: 10.1007/bf02217145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The serum 25-OHD3 concentrations were measured in 16 normal subjects and in 12 haemodialysed patients with chronic renal failure. The mean values found in the two groups were 27.8 +/- 17.8 ng/ml and 23.9 +/- 12 ng/ml, respectively. The difference between the two values is not significant.
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143
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Takasaki Y, Horiuchi N, Takahashi N, Abe E, Shinki T, Suda T, Yamada S, Takayama H, Horikawa H, Masumura T, Sugahara M. Isolation and identificaton of 25-hydroxy-24-oxocholecalciferol: a metabolite of 25-hydroxycholecalciferol. Biochem Biophys Res Commun 1980; 95:177-81. [PMID: 7417247 DOI: 10.1016/0006-291x(80)90720-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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144
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Jones G, Schnoes HK, Levan L, Deluca HF. Isolation and identification of 24-hydroxyvitamin D2 and 24,25-dihydroxyvitamin D2. Arch Biochem Biophys 1980; 202:450-7. [PMID: 6970013 DOI: 10.1016/0003-9861(80)90449-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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145
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Monnier LH, Colette C, Ribot C, Mion C, Mirouze J. Evidence for 25-hydroxyvitamin D deficiency as a factor contributing to osteopenia in diabetic patients with idiopathic haemochromatosis. Eur J Clin Invest 1980; 10:183-7. [PMID: 6783413 DOI: 10.1111/j.1365-2362.1980.tb00018.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Osteopenia is frequently encountered in the course of idiopathic haemochromatosis. In order to establish the mechanism of this bone disorder, the following parameters were studied in nine diabetic patients wih idiopathic haemochromatosis: (i) the intestinal calcium absorption measured by using a double radiotracer technique; (ii) the bone mineral content (BMC, mg/cm2) determined on the forearm by the Cameron's absorptiometric technique, (iii) the plasma 25 hydroxyvitamin D (25-OH-D ng/ml) by a competitive protein-binding radioassay. The results were compared to those obtained in ten controls and in eight diabetics without haemochromatosis. The patients suffering from haemochromatosis had a significant fall in total fractional absorption of calcium and BMC as compared with controls and diabetics without haemochromatosis. Furthermore plasma 25-OH-D was significantly lower in haemochromatosis patients (5.1 +/- 0.6 ng/ml) than in controls (16.4 +/- 1.3 ng/ml, P less than 0.01) and in diabetics without haemochromatosis (14.2 +/- 1.4 ng/ml, P less than 0.02). These results indicate that haemochromatosis patients exhibit important disturbances in calcium homeostasis, i.e. low concentration of plasma 25-OH-D and reduced intestinal absorption of calcium. The latter abnormalities may well be related to the bone rarefaction observed in these patients.
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146
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DeLuca HF. William C. Rose lectureship in biochemistry and nutrition. Some new concepts emanating from a study of the metabolism and function of Vitamin D. Nutr Rev 1980; 38:169-82. [PMID: 7010229 DOI: 10.1111/j.1753-4887.1980.tb05887.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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147
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Meredith SC, Rosenberg IH. Gastrointestinal-hepatic disorders and osteomalacia. CLINICS IN ENDOCRINOLOGY AND METABOLISM 1980; 9:131-50. [PMID: 6998607 DOI: 10.1016/s0300-595x(80)80024-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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148
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149
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Sklan D. Thin layer--gas chromatographic determination of 25-hydroxycholecalciferol. Methods Enzymol 1980; 67:355-7. [PMID: 7366439 DOI: 10.1016/s0076-6879(80)67044-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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150
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McClain RM, Langhoff L, Hoar RM. Reproduction studies with 1 alpha, 25-dihydroxyvitamin D3 (calcitriol) in rats and rabbits. Toxicol Appl Pharmacol 1980; 52:89-98. [PMID: 7361316 DOI: 10.1016/0041-008x(80)90251-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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