Plasma levels of vitamin D and some metabolites in marine mammals

1988 ◽  
Vol 66 (6) ◽  
pp. 1297-1300 ◽  
Author(s):  
K. M. Keiver ◽  
K. Ronald ◽  
H. H. Draper
Keyword(s):  
Vitamin D ◽  
Plasma Levels ◽  
Marine Mammals ◽  
Plasma Calcium ◽  
Cetacean Species ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
25 Hydroxyvitamin D ◽  
Very High

Levels of vitamin D, 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and calcium were determined in the plasma of various captive and wild pinniped and cetacean species. Vitamin D (< 0.4–5 ng∙mL−1) and 25-hydroxyvitamin D (4–84 ng∙mL−1) levels in the pinniped plasma were similar to those found in nonmarine mammals. 24,25-Dihydroxyvitamin D levels in seals (3–48 ng∙mL−1) were high compared with those of other mammals, and the ratios of 24,25-dihydroxyvitamin D to 25-hydroxyvitamin D in fasting pups were extremely high. The belugas and bottlenosed dolphins had very high levels of both 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D compared with the pinnipeds and other mammals, but plasma calcium levels were normal for these species of cetaceans.

Calcium, Vitamin D and Parathyroid Hormone Relationships in Pregnant Caucasian and Asian Women and Their Neonates

1987 ◽  
Vol 24 (1) ◽  
pp. 22-28 ◽  
Author(s):  
F Okonofua ◽  
R K Menon ◽  
S Houlder ◽  
M Thomas ◽  
D Robinson ◽  
...  
Keyword(s):  
Vitamin D ◽  
Parathyroid Hormone ◽  
Inverse Correlation ◽  
Plasma Calcium ◽  
Asian Women ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
The Face ◽  
25 Hydroxyvitamin D ◽  
Caucasian Women

Plasma calcium, serum 25 hydroxyvitamin D [25(OH)D], 1,25 dihydroxyvitamin D[1,25(OH)2D] and parathyroid hormone (PTH) have been measured in pregnant and newborn Caucasians and Asians. Calcium and 25(OH)D concentrations were lower in Caucasian than in Asian women at all four stages (three trimesters and during labour) of pregnancy. PTH concentrations were greater in Asian than in Caucasian women during the three trimesters, but not at labour, and increased in both groups through pregnancy, without a concomitant change in plasma calcium concentrations. There was a significant inverse correlation between calcium and PTH, as well as 25(OH)D and PTH, concentrations. These data demonstrate the presence of progressive ‘hyperparathyroidism’ during pregnancy in Caucasian and Asian women. The higher PTH concentrations in Asian women may reflect the necessity of maintaining adequate plasma calcium concentrations through PTH-induced osteolysis in the face of vitamin D deficiency. Relative hyperparathyroidism in Asians may contribute to net loss of calcium from the skeleton and osteopenia in Asian women. Calcium, 25(OH)D and l,25(OH)2D concentrations were lower, and those of PTH higher, in Asian newborns compared with Caucasian newborns. Serum 1,25(OH)2D concentrations in the Asian newborn, though lower than respective maternal levels, were comparable with normal adult levels, indicating that 1,25(OH)2D biosynthesis is stimulated in the Asian newborn to compensate for the low serum 25(OH)D concentrations.

scholarly journals Plasma 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and parathyroid hormone in familial hypocalciuric hypercalcemia and primary hyperparathyroidism

2008 ◽  
Vol 159 (6) ◽  
pp. 719-727 ◽  
Author(s):  
Signe Engkjær Christensen ◽  
Peter H Nissen ◽  
Peter Vestergaard ◽  
Lene Heickendorff ◽  
Lars Rejnmark ◽  
...  
Keyword(s):  
Vitamin D ◽  
Parathyroid Hormone ◽  
Primary Hyperparathyroidism ◽  
Plasma Levels ◽  
Familial Hypocalciuric Hypercalcemia ◽  
Vitamin D Metabolism ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
25 Hydroxyvitamin D

IntroductionFamilial hypocalciuric hypercalcemia (FHH) is a lifelong, benign, inherited condition caused by inactivating mutations in the calcium-sensing receptor (CASR) gene. Both FHH and primary hyperparathyroidism (PHPT) are characterized by elevated P-calcium, normal or elevated plasma-parathyroid hormone (P-PTH), and typically normal renal function. In PHPT, vitamin D metabolism is typically characterized by low plasma levels of 25-hydroxyvitamin D (25OHD), and high plasma levels of 1,25-dihydroxyvitamin D (1,25(OH)2D). In FHH, the vitamin D metabolism is not very well known.ObjectiveTo compare and evaluate plasma 25OHD, 1,25(OH)2D, and PTH in FHH and PHPT.DesignCross-sectional study.MaterialsAbout 66 FHH patients with mutations in the CASR gene, 147 patients with surgically verified PHPT, and 46 controls matched to FHH patients according to age (±5 years), sex, and season. All patients had a P-creatinine <140 μmol/l.MethodsWe measured P-calcium, P-Ca2+, P-albumin, P-creatinine, P-phosphate, P-magnesium, and P-PTH by standard laboratory methods. P-25OHD and P-1,25(OH)2D were measured by RIA or enzyme immunoassay. In FHH, all protein-coding exons in the CASR gene were sequenced and aligned to GenBank reference sequence .ResultsPHPT patients had higher body mass index (2p<0.01), together with higher P-PTH (2p<0.01) and P-1,25(OH)2D (2p<0.01) compared with FHH patients. The groups had similar levels of P-Ca2+ and of P-25OHD. The phenotypic expression of the CASR mutations (as determined by the degree of hypercalcemia) did not influence the levels of P-1,25(OH)2D.ConclusionEven though P-calcium and P-25OHD were comparable, P-1,25(OH)2D and P-PTH differed between FHH and PHPT.

scholarly journals Vitamin D upregulates the macrophage complement receptor immunoglobulin in innate immunity to microbial pathogens

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Annabelle G. Small ◽  
Sarah Harvey ◽  
Jaspreet Kaur ◽  
Trishni Putty ◽  
Alex Quach ◽  
...  
Keyword(s):  
Vitamin D ◽  
Innate Immunity ◽  
Surface Expression ◽  
Microbial Pathogens ◽  
Cell Surface Expression ◽  
Complement Receptor ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
Multistep Process ◽  
25 Hydroxyvitamin D

AbstractVitamin D deficiency remains a global concern. This ‘sunshine’ vitamin is converted through a multistep process to active 1,25-dihydroxyvitamin D3 (1,25D), the final step of which can occur in macrophages. Here we demonstrate a role for vitamin D in innate immunity. The expression of the complement receptor immunoglobulin (CRIg), which plays an important role in innate immunity, is upregulated by 1,25D in human macrophages. Monocytes cultured in 1,25D differentiated into macrophages displaying increased CRIg mRNA, protein and cell surface expression but not in classical complement receptors, CR3 and CR4. This was associated with increases in phagocytosis of complement opsonised Staphylococcus aureus and Candida albicans. Treating macrophages with 1,25D for 24 h also increases CRIg expression. While treating macrophages with 25-hydroxyvitamin D3 does not increase CRIg expression, added together with the toll like receptor 2 agonist, triacylated lipopeptide, Pam3CSK4, which promotes the conversion of 25-hydroxyvitamin D3 to 1,25D, leads to an increase in CRIg expression and increases in CYP27B1 mRNA. These findings suggest that macrophages harbour a vitamin D-primed innate defence mechanism, involving CRIg.

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 Status and Seasonal Variation among Danish Children and Adults: A Descriptive Study

Nutrients ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1801 ◽  
Author(s):  
Louise Hansen ◽  
Anne Tjønneland ◽  
Brian Køster ◽  
Christine Brot ◽  
Rikke Andersen ◽  
...  
Keyword(s):  
Vitamin D ◽  
Seasonal Variation ◽  
Vitamin D Status ◽  
Hydroxyvitamin D ◽  
Supplement Use ◽  
Wide Range ◽  
Adults And Children ◽  
25 Hydroxyvitamin D ◽  
Vitamin D Supplement ◽  
Very High

The aim of the present study was to describe vitamin D status and seasonal variation in the general Danish population. In this study, 3092 persons aged 2 to 69 years (2565 adults, 527 children) had blood drawn twice (spring and autumn) between 2012 and 2014. A sub-sample of participants had blood samples taken monthly over a year. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were measured by liquid chromatography mass spectrometry, and information on supplement use was assessed from questionnaires. Seasonal variations in 25(OH)D concentrations were evaluated graphically and descriptively, and status according to age, sex, and supplement use was described. It was found that 86% of both adults and children were vitamin D-sufficient in either spring and or/autumn; however, many had a spring concentration below 50 nmol/L. A wide range of 25(OH)D concentrations were found in spring and autumn, with very low and very high values in both seasons. Among adults, women in general had higher median 25(OH)D concentrations than men. Furthermore, vitamin D supplement use was substantial and affected the median concentrations markedly, more so during spring than autumn. Seasonal variation was thus found to be substantial, and bi-seasonal measurements are vital in order to capture the sizable fluctuations in vitamin D status in this Nordic population.

Responses of serum calcium and phosphorus in the frog Rana tigrina to injection of various vitamin D analogs

1987 ◽  
Vol 65 (8) ◽  
pp. 2111-2112 ◽  
Author(s):  
Ajai K. Srivastav ◽  
L. Rani ◽  
K. Swarup
Keyword(s):  
Vitamin D ◽  
Serum Calcium ◽  
Vitamin D Analogs ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Rana Tigrina ◽  
Calcium Deposits ◽  
25 Hydroxyvitamin D ◽  
Calcium And Phosphorus

Intraperitoneal injections of either vitamin D3 (4 IU/100 g body wt.), 25 hydroxyvitamin D3 (100 ng/100 g body wt.), or 1,25 dihydroxyvitamin D3 (100 ng/100 g body wt.) for 15 days induced hypercalcemia, hyperphosphatemia, and depletion of calcium deposits in the paravertebral lime sacs in an anuran, Rana tigrina.

scholarly journals Regulation of vitamin D-1alpha-hydroxylase and -24-hydroxylase expression by dexamethasone in mouse kidney

2000 ◽  
Vol 164 (3) ◽  
pp. 339-348 ◽  
Author(s):  
N Akeno ◽  
A Matsunuma ◽  
T Maeda ◽  
T Kawane ◽  
N Horiuchi
Keyword(s):  
Vitamin D ◽  
Enzyme Activity ◽  
Mrna Expression ◽  
Direct Action ◽  
Plasma Concentrations ◽  
Mrna Abundance ◽  
Subcutaneous Injections ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
25 Hydroxyvitamin D

We investigated the effects of dexamethasone on vitamin D-1alpha-hydroxylase and -24-hydroxylase expression and on vitamin D receptor (VDR) content in the kidneys of mice fed either a normal (NCD) diet or a calcium- and vitamin D-deficient (LCD) diet for 2 weeks. For the last 5 days mice received either vehicle or dexamethasone (2 mg/kg per day s.c.). Dexamethasone significantly increased plasma calcium concentrations without changing plasma concentrations of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) in both NCD and LCD groups. Northern blot and enzyme activity analyses in NCD mice revealed that dexamethasone increased renal VDR mRNA expression modestly and greatly increased 24-hydroxylase mRNA abundance and enzyme activity, but did not affect 1alpha-hydroxylase mRNA abundance and enzyme activity. In mice fed an LCD diet, dexamethasone increased renal VDR mRNA expression 1.5-fold, decreased 1alpha-hydroxylase mRNA abundance (52%) and activity (34%), and markedly increased 24-hydroxylase mRNA abundance (16-fold) and enzyme activity (9-fold). Dexamethasone treatment did not alter functional VDR number (B(max) 125-141 fmol/mg protein) or ligand affinity (K(d) 0.13-0.10 nM) in LCD mice. Subcutaneous injections of 1,25(OH)(2)D(3) (0.24 nmol/kg per day for 5 days) into NCD mice strongly increased renal 24-hydroxylase mRNA abundance and enzyme activity, while there was no effect of dexamethasone on renal 24-hydroxylase expression in these mice. This may be due to overwhelming induction of 24-hydroxylase by 1,25(OH)(2)D(3). These findings suggest that glucocorticoid-induced osteoporosis is caused by direct action of the steroids on bone, and the regulatory effect of glucocorticoids on renal 25-hydroxyvitamin D(3) metabolism may be less implicated in the initiation and progression of the disease.

Cyclosporin a and Vitamin D Metabolism: Studies in Patients with Psoriasis and in Rats

1994 ◽  
Vol 86 (5) ◽  
pp. 627-632 ◽  
Author(s):  
A. J. Shaw ◽  
M. E. Hayes ◽  
M. Davies ◽  
B. D. Edwards ◽  
F. W. Ballardie ◽  
...  
Keyword(s):  
Vitamin D ◽  
Synovial Fluid ◽  
Cyclosporin A ◽  
Severity Index ◽  
Hydroxylase Activity ◽  
Local Synthesis ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
25 Hydroxyvitamin D

1. Cyclosporin A, an immunosuppressive drug used to treat psoriasis, stimulates renal synthesis of 1,25-dihydroxyvitamin D in rats. 1,25-Dihydroxy vitamin D can also reduce the activity of psoriasis, and in the present study we have examined the possibility that cyclosporin A mediates some of its actions in psoriasis by renal or extra-renal production of 1,25-dihydroxyvitamin D. 2. Treatment of 12 psoriatic patients with cyclosporin A (5 mg day−1 kg−1) for 3 months significantly improved the psoriasis activity and severity index and reduced glomerular filtration rate, but serum 1,25-dihydroxyvitamin D levels were not changed. However, 1–3 months after stopping cyclosporin A treatment, an increase in the psoriasis activity and severity index score was accompanied by a small, but significant, increase in serum 1,25-dihydroxyvitamin D concentration. Plasma 1,25-dihydroxyvitamin D levels in rats gavaged with cyclosporin A (15 mg day−1 kg−1 for 2 weeks) were significantly increased compared with controls, but a lower dose of cyclosporin A (2.4 mg day−1 kg−1) had no effect. Renal 25-hydroxyvitamin D-24-hydroxylase activity in rat kidney homogenates was not different between control and cyclosporin A-treated rats. Renal 25-hydroxyvitamin D-1α-hydroxylase activity was not detectable in these homogenates. Extra-renal production of 1,25-dihydroxyvitamin D by activated macrophages isolated from the synovial fluid of patients with inflammatory arthritis was reduced after incubation with cyclosporin A (0.1–10 μmol/l) for 30 h or 5 days. 3. It is unlikely that alteration of circulating 1,25-dihydroxyvitamin D concentration is one of the modes of action of cyclosporin A in psoriasis. Since cyclosporin A inhibits 1,25-dihydroxyvitamin D production by activated synovial fluid macrophages, it is unlikely that cyclosporin A mediates some of its therapeutic actions by local synthesis of 1,25-dihydroxyvitamin D within the psoriatic lesion.

Vitamin D and Calcitonin Treatment in Patients with Femoral Neck Fracture: A Prospective Controlled Clinical Study

1989 ◽  
Vol 17 (3) ◽  
pp. 226-242 ◽  
Author(s):  
E. Harju ◽  
R. Punnonen ◽  
R. Tuimala ◽  
J. Salmi ◽  
I. Paronen
Keyword(s):  
Vitamin D ◽  
Parathyroid Hormone ◽  
Serum Levels ◽  
Serum Calcitonin ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Age Related ◽  
Neck Fracture ◽  
25 Hydroxyvitamin D

The effects on general and bone metabolism of femoral neck fracture patients of 0.25 μg α-calcoid given orally twice daily ( n=9) and 25 μg calcitonin given subcutaneously 30 times ( n=10) in 10 weeks were studied against a control ( n=ll). Bone histology and histomorphometry showed non-age related osteoporosis in 30% and osteomalacia in 22% of the patients studied. Impaired serum vitamin D status was found in 47 – 88% of patients, secondary hyperparathyroidism and increased serum parathyroid hormone in 59% and decreased serum calcitonin levels in 69%. On histology, normal findings and non-age related osteoporosis on histology were associated with low serum levels of 25-hydroxyvitamin D3,1,25- and 24,25-dihydroxy vitamin D3. Very high serum levels of 1,25-dihydroxyvitamin D3 and low levels of 25-hydroxyvitamin D3 occurred in fracture patients with osteomalacia. Calcitonin improved calcium balance, reduced osteoporosis and increased the serum 1,25- and 24,25-dihydroxyvitamin D3 levels but had no effect on osteomalacia. Vitamin D reduced osteomalacia, slightly increased the serum 1,25-dihydroxyvitamin D3 concentration and decreased serum levels of parathyroid hormone. Both treatments gave a similar slight decrease in serum calcitonin concentrations. A mechanism of action for the treatments is suggested.

scholarly journals The Role of the Intraplaque Vitamin D System in Atherogenesis

Scientifica ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Federico Carbone ◽  
Fabrizio Montecucco
Keyword(s):  
Vitamin D ◽  
Clinical Findings ◽  
Peripheral Tissues ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
Mouse Tissues ◽  
Calcium Phosphorus ◽  
25 Hydroxyvitamin D ◽  
Physiological Pathways

Vitamin D has been shown to play critical activities in several physiological pathways not involving the calcium/phosphorus homeostasis. The ubiquitous distribution of the vitamin D receptor that is expressed in a variety of human and mouse tissues has strongly supported research on these “nonclassical” activities of vitamin D. On the other hand, the recent discovery of the expression also for vitamin D-related enzymes (such as 25-hydroxyvitamin D-1α-hydroxylase and the catabolic enzyme 1,25-dihydroxyvitamin D-24-hydroxylase) in several tissues suggested that the vitamin D system is more complex than previously shown and it may act within tissues through autocrine and paracrine pathways. This updated model of vitamin D axis within peripheral tissues has been particularly investigated in atherosclerotic pathophysiology. This review aims at updating the role of the local vitamin D within atherosclerotic plaques, providing an overview of both intracellular mechanisms and cell-to-cell interactions. In addition, clinical findings about the potential causal relationship between vitamin D deficiency and atherogenesis will be analysed and discussed.

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