scholarly journals A Novel Rat Model of Vitamin D Deficiency: Safe and Rapid Induction of Vitamin D and Calcitriol Deficiency without Hyperparathyroidism

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Andrea W. D. Stavenuiter ◽  
Maria Vittoria Arcidiacono ◽  
Evelina Ferrantelli ◽  
Eelco D. Keuning ◽  
Marc Vila Cuenca ◽  
...  
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Hypovitaminosis D ◽  
Vitamin D Metabolites ◽  
Deficient Diet ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
Study Results ◽  
Wide Range ◽  
Serum Pth

Vitamin D deficiency is associated with a range of clinical disorders. To study the mechanisms involved and improve treatments, animal models are tremendously useful. Current vitamin D deficient rat models have important practical limitations, including time requirements when using, exclusively, a vitamin D deficient diet. More importantly, induction of hypovitaminosis D causes significant fluctuations in parathyroid hormone (PTH) and mineral levels, complicating the interpretation of study results. To overcome these shortcomings, we report the successful induction of vitamin D deficiency within three weeks, with stable serum PTH and minerals levels, in Wistar rats. We incorporated two additional manoeuvres compared to a conventional diet. Firstly, the vitamin D depleted diet is calcium (Ca) enriched, to attenuate the development of secondary hyperparathyroidism. Secondly, six intraperitoneal injections of paricalcitol during the first two weeks are given to induce the rapid degradation of circulating vitamin D metabolites. After three weeks, serum 25-hydroxyvitamin D3(25D) and 1,25-dihydroxyvitamin D3(1,25D) levels had dropped below detection limits, with unchanged serum PTH, Ca, and phosphate (P) levels. Therefore, this model provides a useful tool to examine the sole effect of hypovitaminosis D, in a wide range of research settings, without confounding changes in PTH, Ca, and P.

A simplified assay for dihydroxylated vitamin D metabolites in human serum: application to hyper- and hypovitaminosis D.

1980 ◽  
Vol 26 (3) ◽  
pp. 444-450 ◽  
Author(s):  
R S Mason ◽  
D Lissner ◽  
H S Grunstein ◽  
S Posen
Keyword(s):  
Vitamin D ◽  
Human Serum ◽  
Hypovitaminosis D ◽  
Reference Interval ◽  
Vitamin D Metabolites ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Vitamin D Intoxication ◽  
25 Hydroxyvitamin D

Abstract We describe a simplified assay for 24,25-and 1.25-dihydroxyvitamin D in human serum. It involves two preparative steps, and normal chick intestine is used in preparing cytosol-binding protein. Our results for 24,25-dihydroxyvitamin D include a reference interval of 2.9—16 nmol/L (1.2—6.7 microgram/L), a mean of 6.7 nmol/L (2.8 microgram/L), an intra-assay CV of 11%, and an interassay CV of 22%. For 1,25-dihydroxyvitamin D, these data were 29—168 pmol/L (12—70 ng/L), 86 pmol/L (36 ng/L), 12%, and 22%, respectively. In hypoparathyroid patients with vitamin D intoxication, mean concentrations of 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D in serum were significantly above normal; the 1,25-dihydroxyvitamin D concentrations were significantly below normal. Patients with malabsorption and/or post-gastrectomy states had significantly subnormal values for both 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D in serum, and there was a significantly negative correlation between each of these biochemical values and the severity of osteomalacia. We also discuss cost effectiveness of assaying vitamin D metabolites in human serum.

Effects of parathyroid hormone on puppies during development of Ca and vitamin D deficiency

1985 ◽  
Vol 249 (6) ◽  
pp. E568-E576 ◽  
Author(s):  
K. M. Wong ◽  
L. Klein ◽  
B. Hollis
Keyword(s):  
Vitamin D ◽  
Bone Resorption ◽  
Vitamin D Deficiency ◽  
Maximal Response ◽  
Deficient Diet ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
25 Hydroxyvitamin D ◽  
Entire Experiment ◽  
Parathyroid Extract

The acute effects of parathyroid extract (PTE) were studied repeatedly in young dogs (prelabeled with 45Ca and [3H]tetracycline) during the development of calcium (Ca) and vitamin D deficiency. Blood Ca and radioactivity changes were monitored sequentially after subcutaneous PTE, injected seven times over 63 days. In control dogs, all sequential responses to acute PTE challenges were constant in both magnitude of increase and time at which maximum response occurred over the entire experiment. Under chronic Ca and D deficiency, plasma 25-hydroxyvitamin D in experimental dogs decreased continuously to very low levels at 63 days, whereas 1,25-dihydroxyvitamin D initially increased to a maximum at 32 days and thereafter decreased. In response to an acute challenge of PTE, dogs on the deficient diet for 3 and 10 days showed a greater response of blood Ca and 45Ca than the controls but subsequently showed a smaller response than controls after 49 and 63 days on the deficient diet. Compared with control dogs, the time of maximal response of blood Ca and 45Ca to PTE occurred much earlier in dogs that were on the deficient diet for 35-63 days. The blood [3H]tetracycline response (index of bone resorption) to exogenous PTE in the deficient dogs, however, was constant and similar to that of the control dogs during the entire period. The data suggest that the bone resorption response to PTE was normal in Ca- and D-deficient puppies with hypocalcemia.(ABSTRACT TRUNCATED AT 250 WORDS)

A simplified assay for dihydroxylated vitamin D metabolites in human serum: application to hyper- and hypovitaminosis D.

1980 ◽  
Vol 26 (3) ◽  
pp. 444-450 ◽  
Author(s):  
R S Mason ◽  
D Lissner ◽  
H S Grunstein ◽  
S Posen
Keyword(s):  
Vitamin D ◽  
Human Serum ◽  
Hypovitaminosis D ◽  
Reference Interval ◽  
Vitamin D Metabolites ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Vitamin D Intoxication ◽  
25 Hydroxyvitamin D

Abstract We describe a simplified assay for 24,25-and 1.25-dihydroxyvitamin D in human serum. It involves two preparative steps, and normal chick intestine is used in preparing cytosol-binding protein. Our results for 24,25-dihydroxyvitamin D include a reference interval of 2.9—16 nmol/L (1.2—6.7 microgram/L), a mean of 6.7 nmol/L (2.8 microgram/L), an intra-assay CV of 11%, and an interassay CV of 22%. For 1,25-dihydroxyvitamin D, these data were 29—168 pmol/L (12—70 ng/L), 86 pmol/L (36 ng/L), 12%, and 22%, respectively. In hypoparathyroid patients with vitamin D intoxication, mean concentrations of 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D in serum were significantly above normal; the 1,25-dihydroxyvitamin D concentrations were significantly below normal. Patients with malabsorption and/or post-gastrectomy states had significantly subnormal values for both 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D in serum, and there was a significantly negative correlation between each of these biochemical values and the severity of osteomalacia. We also discuss cost effectiveness of assaying vitamin D metabolites in human serum.

scholarly journals Vitamin D-Mediated Hypercalcemia: Mechanisms, Diagnosis, and Treatment

2016 ◽  
Vol 37 (5) ◽  
pp. 521-547 ◽  
Author(s):  
Peter J. Tebben ◽  
Ravinder J. Singh ◽  
Rajiv Kumar
Keyword(s):  
Vitamin D ◽  
Vitamin D Receptor ◽  
Active Form ◽  
Elevated Serum ◽  
Diagnosis And Treatment ◽  
Vitamin D Metabolites ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
Stone Formers ◽  
25 Hydroxyvitamin D

AbstractHypercalcemia occurs in up to 4% of the population in association with malignancy, primary hyperparathyroidism, ingestion of excessive calcium and/or vitamin D, ectopic production of 1,25-dihydroxyvitamin D [1,25(OH)2D], and impaired degradation of 1,25(OH)2D. The ingestion of excessive amounts of vitamin D3 (or vitamin D2) results in hypercalcemia and hypercalciuria due to the formation of supraphysiological amounts of 25-hydroxyvitamin D [25(OH)D] that bind to the vitamin D receptor, albeit with lower affinity than the active form of the vitamin, 1,25(OH)2D, and the formation of 5,6-trans 25(OH)D, which binds to the vitamin D receptor more tightly than 25(OH)D. In patients with granulomatous disease such as sarcoidosis or tuberculosis and tumors such as lymphomas, hypercalcemia occurs as a result of the activity of ectopic 25(OH)D-1-hydroxylase (CYP27B1) expressed in macrophages or tumor cells and the formation of excessive amounts of 1,25(OH)2D. Recent work has identified a novel cause of non-PTH-mediated hypercalcemia that occurs when the degradation of 1,25(OH)2D is impaired as a result of mutations of the 1,25(OH)2D-24-hydroxylase cytochrome P450 (CYP24A1). Patients with biallelic and, in some instances, monoallelic mutations of the CYP24A1 gene have elevated serum calcium concentrations associated with elevated serum 1,25(OH)2D, suppressed PTH concentrations, hypercalciuria, nephrocalcinosis, nephrolithiasis, and on occasion, reduced bone density. Of interest, first-time calcium renal stone formers have elevated 1,25(OH)2D and evidence of impaired 24-hydroxylase-mediated 1,25(OH)2D degradation. We will describe the biochemical processes associated with the synthesis and degradation of various vitamin D metabolites, the clinical features of the vitamin D-mediated hypercalcemia, their biochemical diagnosis, and treatment.

scholarly journals Vitamin D signalling in adipose tissue

2012 ◽  
Vol 108 (11) ◽  
pp. 1915-1923 ◽  
Author(s):  
Cherlyn Ding ◽  
Dan Gao ◽  
John Wilding ◽  
Paul Trayhurn ◽  
Chen Bing
Keyword(s):  
Vitamin D ◽  
Adipose Tissue ◽  
Vitamin D Deficiency ◽  
Vitamin D Metabolites ◽  
Hydroxyvitamin D ◽  
The Metabolic Syndrome ◽  
Prevalence Of Obesity ◽  
Adipose Tissue Development ◽  
And Function

Vitamin D deficiency and the rapid increase in the prevalence of obesity are both considered important public health issues. The classical role of vitamin D is in Ca homoeostasis and bone metabolism. Growing evidence suggests that the vitamin D system has a range of physiological functions, with vitamin D deficiency contributing to the pathogenesis of several major diseases, including obesity and the metabolic syndrome. Clinical studies have shown that obese individuals tend to have a low vitamin D status, which may link to the dysregulation of white adipose tissue. Recent studies suggest that adipose tissue may be a direct target of vitamin D. The expression of both the vitamin D receptor and 25-hydroxyvitamin D 1α-hydroxylase (CYP27B1) genes has been shown in murine and human adipocytes. There is evidence that vitamin D affects body fat mass by inhibiting adipogenic transcription factors and lipid accumulation during adipocyte differentiation. Some recent studies demonstrate that vitamin D metabolites also influence adipokine production and the inflammatory response in adipose tissue. Therefore, vitamin D deficiency may compromise the normal metabolic functioning of adipose tissue. Given the importance of the tissue in energy balance, lipid metabolism and inflammation in obesity, understanding the mechanisms of vitamin D action in adipocytes may have a significant impact on the maintenance of metabolic health. In the present review, we focus on the signalling role of vitamin D in adipocytes, particularly the potential mechanisms through which vitamin D may influence adipose tissue development and function.

scholarly journals Vitamin D i pokazateli kal'tsiy-fosfornogo obmenau detey, prozhivayushchikh v sredney polose Rossii, v periodmaksimal'noy insolyatsii

2010 ◽  
Vol 13 (2) ◽  
pp. 2-6 ◽  
Author(s):  
A. V. Vitebskaya ◽  
G. E. Smirnova ◽  
A. V. Il'in
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Central Area ◽  
Hypovitaminosis D ◽  
Vitamin D Insufficiency ◽  
Winter Period ◽  
Published Data ◽  
Healthy Children ◽  
Hydroxyvitamin D ◽  
Oncological Diseases

Vitamin D deficiency is associated with rickets in children and osteomalation in adults. Published data support the role of vitamin D insufficiency in development of autoimmune, cardiovascular and oncological diseases. The most precise method to diagnose vitamin D insufficiency is measuring of 25-hydroxyvitamin D (25(OH)-D). We studded the levels of vitamin D and calcium-phosphate turnover parameters during the period of maximal insolation in 140 healthy children and adolescents permanently living in the central area of Russia. Vitamin D insufficiency (25(OH)-D < 20 ng/ml) was detected in 38,6%; in 2,9% of them severe vitamin D deficiency was diagnosed (25(OH)-D < 8 ng/ml). The results correlate with data on hypovitaminosis D prevalence in countries with the same geographical latitude. To clarify the real size of required prophylaxis we need investigation of the same parameters in winter period while minimal insolation.

scholarly journals Levels of vitamin D among overweight and obese adolescents: an observational study

2017 ◽  
Vol 4 (6) ◽  
pp. 1934
Author(s):  
T. Prashanth Reddy ◽  
Kishore Reddy ◽  
Madhu Sudhan Reddy ◽  
Manjunath G. A.
Keyword(s):  
Vitamin D ◽  
Observational Study ◽  
Vitamin D Deficiency ◽  
Overweight And Obesity ◽  
Dietary Factors ◽  
Vitamin D Status ◽  
Obese Adolescents ◽  
Vitamin D Levels ◽  
Study Results ◽  
Wide Range

Background: Normal growth and development requires vitamin D, and its deficiency compromises long term health and increases the risk of chronic disease. Severe vitamin D deficiency include rickets, osteomalacia, osteoporosis, increased risk of fracture, tooth loss. Studies indicate that vitamin D insufficiency (less severe than deficiency) is associated with a wide range of illnesses and chronic conditions, including type 1 diabetes, hypertension, multiple sclerosis and many types of cancer. Currently world is facing an unrecognized and untreated pandemic of vitamin D deficiency. This study aims at showing the relation between Vitamin D status and obesity in adolescent children and to know the dietary factors, life style factors like physical activity contributing to overweight and obesity in adolescents.Methods: Study design: This is an observational study of 30 overweight and obese adolescents based on BMI were studied and their Vitamin D levels were assessed.Results: A total of 14(46.7%) overweight and 16(53.3%) obese adolescents Vitamin D levels were assessed. 20(66.7%) had vitamin D levels <20ng/ml that is in the deficiency range.4(13.3%) had in the insufficiency range (21-30ng/ml), 6(20%) had in the sufficient range. Results shows vitamin D levels were significantly less in obese and overweight adolescents.Conclusions: Study results confirm that Vitamin D deficiency or insufficiency is common to obese and overweight adolescents, this may help to explain the relationship between obesity and several chronic diseases that are associated with poor Vitamin D status.

scholarly journals Prolonged treatment with vitamin D in postmenopausal women with primary hyperparathyroidism

2012 ◽  
Vol 1 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Ranganathan R Rao ◽  
Harpal S Randeva ◽  
Sailesh Sankaranarayanan ◽  
Murthy Narashima ◽  
Matthias Möhlig ◽  
...  
Keyword(s):  
Vitamin D ◽  
Primary Hyperparathyroidism ◽  
Vitamin D Deficiency ◽  
Postmenopausal Women ◽  
Prolonged Treatment ◽  
Serum 25Ohd ◽  
Hydroxyvitamin D ◽  
Significant Difference ◽  
25 Hydroxyvitamin D ◽  
Serum Pth

Introduction/backgroundVitamin D deficiency further increases circulating parathyroid hormone (PTH) levels in patients with primary hyperparathyroidism (pHPT), with potential detrimental effects on bone mass.MethodsThis was an observational clinical study in consecutive conservatively treated postmenopausal women (n=40) with pHPT and coexistent 25-hydroxyvitamin D deficiency (25OHD ≤50 nmol/l (≤20 ng/ml)). Patients who showed an increase in serum 25OHD above the threshold of vitamin D deficiency (>50 nmol/l; n=28) using treatment with various commonly prescribed vitamin D preparations were, for the purposes of statistical analyses, allocated to the treatment group. Patients who were retrospectively identified as having received no treatment with vitamin D and/or remained vitamin D deficient were considered as non-responders/controls (n=12). Adjusted calcium (adjCa), PTH and 25OHD concentrations were monitored in all subjects up to 54 months (mean observation period of 18±2 months).ResultsProlonged increased vitamin D intake, regardless of the source (serum 25OHD, increase from 32.2±1.7 nmol/l at baseline to 136.4±11.6 nmol/l, P<0.0001), significantly reduced serum PTH (13.3±1.1 vs 10.5±1.0 pmol/l, P=0.0001), with no adverse effects on adjCa levels (2.60±0.03 vs 2.60±0.02 mmol/l, P=0.77) and renal function tests (P>0.73). In contrast, serum PTH remained unchanged (15.8±2.6 vs 16.3±1.9 pmol/l, P=0.64) in patients who remained vitamin D deficient, with a significant difference between groups in changes of PTH (P=0.0003). Intrapartial correlation analyses showed an independent negative correlation of changes in 25OHD with PTH levels (ric=−0.41, P=0.014).ConclusionsProlonged treatment with vitamin D in various commonly prescribed preparations appeared to be safe and significantly reduced PTH levels by 21%.

Calcium Malabsorption in Elderly Women with Vertebral Fractures: Evidence for Resistance to the Action of Vitamin D Metabolites on the Bowel

1984 ◽  
Vol 66 (1) ◽  
pp. 103-107 ◽  
Author(s):  
R. M. Francis ◽  
M. Peacock ◽  
G. A. Taylor ◽  
J. H. Storer ◽  
B. E. C. Nordin
Keyword(s):  
Vitamin D ◽  
Vertebral Fractures ◽  
Calcium Absorption ◽  
Elderly Women ◽  
Vitamin D Metabolites ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
Significant Difference ◽  
Before And After ◽  
Calcium Malabsorption

1. Radio-calcium absorption, plasma 25-hydroxyvitamin D [25-(OH)D] and 1,25-dihydroxyvitamin D [1,25-(OH)2D] concentrations were measured in 19 elderly women with, and 21 without, vertebral fractures, before and after treatment with 25-hydroxyvitamin D3 [25-(OH)D3], to establish whether malabsorption of calcium in elderly women with vertebral fractures has a cause different from that in elderly women without vertebral fractures. 2. Malabsorption of calcium and low plasma 25-(OH)D and 1,25-(OH)2D concentrations were common in both groups of women but there was no significant difference in these variables between the two groups. 3. After treatment with 40 μg of 25-(OH)D3 daily for 7 days, there was a significant increase in plasma 25-(OH)D and 1,25-(OH)2D in both groups of women, but radio-calcium absorption increased significantly only in the group without vertebral fractures. 4. Elderly women with vertebral fractures have malabsorption of calcium which is resistant to the action of vitamin D metabolites at concentrations which correct calcium malabsorption in elderly women without vertebral fractures.

Vitamin D metabolites regulate osteocalcin synthesis and proliferation of human bone cells in vitro

1985 ◽  
Vol 105 (3) ◽  
pp. 391-396 ◽  
Author(s):  
H. Skjødt ◽  
J. A. Gallagher ◽  
J. N. Beresford ◽  
M. Couch ◽  
J. W. Poser ◽  
...  
Keyword(s):  
Vitamin D ◽  
Cell Proliferation ◽  
Bone Cells ◽  
Rank Order ◽  
Human Bone ◽  
Dependent Manner ◽  
Vitamin D Metabolites ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D

ABSTRACT The effects of six natural vitamin D metabolites of potential biological and therapeutic interest, 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3), 25-hydroxyvitamin D3 (25-OH-D3), 24R,25-dihydroxyvitamin D3 (24R,25-(OH)2D3), 1,24R,25-trihydroxyvitamin D3 (1,24R,25-(OH)3D3), 25S,26-dihydroxyvitamin D3 (25S,26-(OH)2D3) and 1,25S,26-trihydroxyvitamin D3 (1,25S,26-(OH)3D3) on cell replication and expression of the osteoblastic phenotype in terms of osteocalcin production were examined in cultured human bone cells. At a dose of 5 × 10−12 mol/l, 1,25-(OH)2D3 stimulated cell proliferation, whereas at higher doses (5 × 10−9−5 × 10 −6 mol/l) cell growth was inhibited in a dose-dependent manner. The same pattern of effects was seen for the other metabolites in a rank order of potency: 1,25-(OH)2D3> 1,25S,26-(OH)3D3 = 1,24R,25-(OH)3D3>25S,26-(OH)2D3 = 24R,25-(OH)2D3 = 25-OH-D3. Synthesis of osteocalcin was induced by 1,25-(OH)2D3 in doses similar to those required to inhibit cell proliferation. Biphasic responses were observed for some of the metabolites in terms of osteocalcin synthesis, inhibitory effects becoming apparent at 5 × 10−6 mol/l. The cells did not secrete osteocalcin spontaneously. These results indicate that vitamin D metabolites may regulate growth and expression of differentiated functions of normal human osteoblasts. J. Endocr. (1985) 105, 391–396

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