scholarly journals Effects of vitamin D on calcium regulation in vitamin-D-deficient pigs given a phytate-phosphorus diet

1986 ◽  
Vol 56 (3) ◽  
pp. 661-669 ◽  
Author(s):  
A. Pointillart ◽  
Nicole Fontaine ◽  
Monique Thomasset
Keyword(s):  
Vitamin D ◽  
Alkaline Phosphatase ◽  
Time Course ◽  
Mineral Metabolism ◽  
Calcium Balance ◽  
Vitamin D Metabolites ◽  
Vitamin D Metabolism ◽  
Phytate Phosphorus ◽  
Diet Regimen ◽  
25 Hydroxycholecalciferol

1.Vitamin-D-deficient pigs were fed on a phytate-phosphorus diet and treated with vitamin D, (+D) to examine the time-course of adaptative changes in plasma minerals, vitamin D metabolites, parathyroid hormone (PTH) and calcium balance and intestinal Ca-binding protein (CaBP).2. The 5-week vitamin D repletion (25 μg cholecalciferol/kg diet) regimen restored plasma Ca, P and alkaline phosphatase (EC 3.1.3.1) to normal, decreased PTH and markedly and rapidly increased plasma 25- hydroxycholecalciferol (25-OHD, sevenfold after 4 d) and 1, 25-dihydroxycholecalciferol ( 1, 25(OH)2D3, 1.8-fold after 4 d).3. CaBP concentrations were markedly elevated all along the digestive tract, especially in the distal regions.4. Ca absorption and retention were enhanced (fourfold and sixfold respectively) by the +D diet.5. The improved Ca absorption, coupled with increased CaBP and 1, 25(OH)2D3 levels, suggest that vitamin D metabolism in phytate-P-fed pigs is sensitive to the depressed Ca availability due to phytate feeding. It also indicates that CaBP may play an important role in the adaptation of Ca absorption.6. Persistent hypercalciuria indicates that mineral metabolism was still affected by the phytate nature of the dietary P in spite of the vitamin D treatment.

scholarly journals The localization of 1,25-dihydroxycholecalciferol in bone cell nuclei of rachitic chicks

1971 ◽  
Vol 125 (1) ◽  
pp. 147-153 ◽  
Author(s):  
J. C. Weber ◽  
V. Pons ◽  
E. Kodicek
Keyword(s):  
Vitamin D ◽  
Subcellular Distribution ◽  
Time Course ◽  
Supernatant Fraction ◽  
Intestinal Cell ◽  
Nuclear Fraction ◽  
Vitamin D Metabolites ◽  
Cell Nuclei ◽  
Polar Metabolite ◽  
25 Hydroxycholecalciferol

1. A simple technique has been developed to obtain subcellular fractions of chick bone. The method yielded 60–70% of total DNA in the nuclear debris fraction and 80–90% of total 14C recovered in bone after a dose of radioactive vitamin D. 2. After a dose of [4-14C,1,2-3H2]cholecalciferol (0.5μg) was given to vitamin D-deficient chicks, the time-course of total 14C radioactivity in the epiphysis, metaphysis and diaphysis of proximal tibiae was measured. The maximum concentrations were reached at 6h, corresponding to a similar peak of radioactivity in blood, decreasing until 24h and indicating the dependence on the circulating 14C and on the blood supply of the three bone components. 3. The 14C radioactivity of cholecalciferol and 25-hydroxycholecalciferol (expressed per mg of DNA) followed the pattern of incorporation of total 14C radioactivity in all three bone components. The more polar metabolite fraction reached a peak of radioactivity at 6–9h and maintained its concentration over the 24h period studied in all anatomical bone components. 4. After a dose of [4-14C,1-3H]cholecalciferol (0.5μg) was given to vitamin D-deficient chicks, the subcellular distribution was studied. At 24h after dosing, the nuclear fraction contained 27% and the supernatant fraction had 67% of total 14C recovered in the bone filtrate. When the 14C in the residual bone fragments was included, the nuclear fraction contained up to 35% of the total radioactivity in the bone. 5. The subcellular distribution pattern of individual vitamin D metabolites indicated that the purified nuclear fraction concentrated the polar metabolite, which lost 3H at C-1, so that 77% of the radioactivity could be accounted for by 1,25-dihydroxycholecalciferol. The supernatant fraction contained smaller amounts of 1,25-dihydroxycholecalciferol (9%), with 66% of 25-hydroxycholecalciferol forming the major metabolite, corresponding to its concentration found in blood at 24h. 6. The preferential accumulation of 1,25-dihydroxycholecalciferol in the nuclear fraction and the overall pattern of other metabolites, found previously in intestinal tissue, suggests a similar mechanism of action in bone to that postulated for the intestinal cell in calcium translocation.

Vitamin D metabolism in the Damara mole-rat is altered by exposure to sunlight yet mineral metabolism is unaffected

1994 ◽  
Vol 143 (2) ◽  
pp. 367-374 ◽  
Author(s):  
T Pitcher ◽  
I N Sergeev ◽  
R Buffenstein
Keyword(s):  
Vitamin D ◽  
Mineral Metabolism ◽  
Plasma Concentrations ◽  
Sun Exposure ◽  
Inorganic Phosphorus ◽  
Vitamin D Metabolites ◽  
Vitamin D Metabolism ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
Highly Efficient

Abstract Vitamin D may be endogenously synthezised in the skin in the presence of sunlight or, alternatively, acquired from dietary sources. Cryptomys damarensis appear to have a naturally impoverished vitamin D status with low plasma concentrations of both 25-hydroxyvitamin D (25(OH)D; <5 ng/ml) and 1,25-dihydroxyvitamin D (1,25(OH)2D; <20 pg/ml). We attribute this to their underground habitat and herbivorous habits. We questioned whether these subterranean mammals could utilize sunlight-mediated pathways and therefore compared vitamin D metabolism and function when animals were (a) housed naturally (control), (b) given an oral vitamin D3 (D3) supplement (1 IU/g dry matter food eaten per day) and (c) exposed to 10 h of sunlight. Control animals exhibited a highly efficient apparent fractional absorption of both calcium (Ca) and inorganic phosphorus (Pi) (>90%), passive mode of intestinal mineral uptake, yet tightly regulated serum ionized calcium (Ca2+). The ratio of 25(OH)D-1α-hydroxylase (1-OHase) to 25(OH)D-24R-hydroxylase (24-OHase) activity in the kidney, corresponded with a state of vitamin D deficiency. Cryptomys damarensis responded to both oral D3 supplementation and sun exposure by an increase in plasma concentration of 1,25(OH)2D with a commensurate decline (P<0·05) in 1-OHase activity, and a resulting decrease (P<0·05) in the ratio of 1-OHase:24-OHase activity. Despite these changes, the intestinal mode of Ca uptake and plasma total Ca, Ca2+ and Pi remained unchanged with either treatment. Responses to sunlight were less pronounced than that of oral D3 supplementation. These data confirm that naturally vitamin D-deficient mole-rats can convert vitamin D to the active hormone 1,25(OH)2D, and indicate that mole-rats function optimally at the low concentrations of vitamin D metabolites found naturally. Furthermore, these animals exhibit a highly efficient vitamin D-independent mode of intestinal Ca absorption. Journal of Endocrinology (1994) 143, 367–374

scholarly journals Opposite correlation of 25-hydroxy-vitamin D- and 1,25-dihydroxy-vitamin D-metabolites with gestational age, bone- and lipid-biomarkers in pregnant women

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Oleg Tsuprykov ◽  
Saban Elitok ◽  
Claudia Buse ◽  
Chang Chu ◽  
Bernhard Karl Krämer ◽  
...  
Keyword(s):  
Vitamin D ◽  
Alkaline Phosphatase ◽  
Pregnant Women ◽  
Clinical Chemistry ◽  
Water Soluble ◽  
Target Cells ◽  
Vitamin D Metabolites ◽  
Specific Alkaline Phosphatase ◽  
Bone Specific Alkaline Phosphatase ◽  
Group B

Abstract25-Hydroxyvitamin D (25OHD) and 1,25-dihydroxyvitamin D (1,25(OH)2D) need to be bound to carrier proteins to be transported to their target cells. The majority of either 25OHD or 1,25(OH)2D is bound to vitamin D-binding protein (DBP), a smaller fraction is bound to albumin and only very small amounts of 25OHD or 1,25(OH)2D are free. Albumin-bound 25OHD or 1,25(OH)2D is relatively easily available after dissociation from albumin. Thus, the sum of free and albumin-bound forms is called bioavailable 25OHD and bioavailable 1,25(OH)2D. Total 25OHD and 1,25(OH)2D are defined as the sum of free, albumin-bound and DBP-bound 25OHD and 1,25(OH)2D, respectively. This cross-sectional study in 427 pregnant women compared the correlation of the six vitamin D compounds with biomarkers of bone health, lipid metabolism, kidney function, endocrine parameters, and group B water-soluble vitamins. Among the 25OHD metabolites analysed, total 1,25(OH)2D showed clearly the best correlation with calcium, bone-specific alkaline phosphatase, adiponectin, LDL, HDL, urea, thyroxine, and group B water-soluble vitamins. When comparing the three 25OHD metabolites, both free 25OHD and bioavailable 25OHD showed overall good correlations with calcium, bone-specific alkaline phosphatase, adiponectin, LDL, HDL, urea, thyroxine, triiodothyronine, and group B water-soluble vitamins, The correlations of 1,25(OH)2D and 25OHD metabolites went always in opposite directions. Only PTH correlates always inversely with all six vitamin D compounds. In conclusion, free 25(OH)D and bioavailable 25(OH)D are more precise determinants of the vitamin D status than total 25(OH)D in normal pregnancy, whereas total 1,25(OH)2D is superior to free and bioavailable 1,25(OH)2D. Except for PTH, correlations of 25(OH)D and 1,25(OH)2D metabolites with typical clinical chemistry readouts go in opposite directions.

scholarly journals Implications of Vitamin D Research in Chickens can Advance Human Nutrition and Perspectives for the Future

2021 ◽  
Author(s):  
Matthew F Warren ◽  
Kimberly A Livingston
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Vitamin D Supplementation ◽  
The Body ◽  
Human Nutrition ◽  
Vitamin D Metabolites ◽  
Vitamin D Metabolism ◽  
Related Research ◽  
Vitamin D Intake ◽  
Increased Risk

Abstract The risk of vitamin D insufficiency in humans is a global problem that requires improving ways to increase vitamin D intake. Supplements are a primary means for increasing vitamin D intake, but without a clear consensus on what constitutes vitamin D sufficiency, there is toxicity risk with taking supplements. Chickens have been used in many vitamin D-related research studies, especially studies involving vitamin D supplementation. Our state-of-the-art review evaluates vitamin D metabolism and how the different hydroxylated forms are synthesized. We provide an overview with how vitamin D is absorbed, transported, excreted, and what tissues in the body store vitamin D metabolites. We also discuss a number of studies involving vitamin D supplementation with broilers and laying hens. Vitamin D deficiency and toxicity are also described and how they can be caused. The vitamin D receptor (VDR) is important for vitamin D metabolism. However, there is much more that can be understood with VDR in chickens. Potential research aims involving vitamin D and chickens should explore VDR mechanisms which could lead to newer insights with VDR. Utilizing chickens in future research to help with elucidating vitamin D mechanisms has great potential to advance human nutrition. Finding ways to increase vitamin D intake will be necessary because the coronavirus 2019 disease (COVID-19) pandemic is leading to increased risk of vitamin D deficiency in many populations. Chickens can provide a dual purpose with addressing pandemic-caused vitamin D deficiency: 1) vitamin D supplementation gives chickens added value with possibly leading to vitamin D-enriched meat and egg products; and 2) chickens’ use in research provides data for translational research. Expanding vitamin D-related research in chickens to include more nutritional aims in vitamin D status has great implications with developing better strategies to improve human health.

scholarly journals Evaluation of Vitamin D Metabolism in Patients with Type 1 Diabetes Mellitus in the Setting of Cholecalciferol Treatment

Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3873
Author(s):  
Alexandra Povaliaeva ◽  
Ekaterina Pigarova ◽  
Artem Zhukov ◽  
Viktor Bogdanov ◽  
Larisa Dzeranova ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Vitamin D ◽  
Type 1 Diabetes ◽  
Type 1 Diabetes Mellitus ◽  
Controlled Study ◽  
Affinity Constant ◽  
Vitamin D Metabolites ◽  
Vitamin D Metabolism ◽  
Vitamin D Levels

In this prospective controlled study, we examined 25 adults with adequately controlled (HbA1c level < 8.0%) type 1 diabetes mellitus (T1DM) and 49 conditionally healthy adults, intending to reveal the diversity of vitamin D metabolism in the setting of cholecalciferol intake at a therapeutic dose. All patients received a single dose (150,000 IU) of cholecalciferol aqueous solution orally. Laboratory assessments including serum vitamin D metabolites (25(OH)D3, 25(OH)D2, 1,25(OH)2D3, 3-epi-25(OH)D3 and 24,25(OH)2D3), free 25(OH)D, vitamin D-binding protein (DBP) and parathyroid hormone (PTH) as well as serum and urine biochemical parameters were performed before the intake and on Days 1, 3 and 7 after the administration. The studied groups had no significant differences in baseline parameters except that the patients with diabetes showed higher baseline levels of free 25(OH)D (p < 0.05). They also lacked a correlation between the measured and calculated free 25(OH)D in contrast to the patients from the control group (r = 0.41, p > 0.05 vs. r = 0.88, p < 0.05), possibly due to the glycosylation of binding proteins, which affects the affinity constant for 25(OH)D. The elevation of vitamin D levels after the administration of cholecalciferol was comparable in both groups, with slightly higher 25(OH)D3 levels observed in the diabetes group throughout the study since Day 1 (p < 0.05). Overall, our data indicate that in patients with adequately controlled T1DM 25(OH)D3 levels and the therapeutic response to cholecalciferol is similar to that in healthy individuals.

Effect of Phenobarbitone Treatment on Vitamin D Metabolism in Mammals

1974 ◽  
Vol 46 (4) ◽  
pp. 433-448 ◽  
Author(s):  
J. Silver ◽  
G. Neale ◽  
G. R. Thompson
Keyword(s):  
Vitamin D ◽  
Biological Activity ◽  
Silicic Acid ◽  
Vitamin D3 ◽  
Water Soluble ◽  
Prolonged Treatment ◽  
Vitamin D Metabolism ◽  
Silicic Acid Chromatography ◽  
Polar Metabolites ◽  
25 Hydroxycholecalciferol

1. The metabolism of radioactive cholecalciferol was studied in control and phenobarbitone-treated rats and pigs. 2. Treatment with phenobarbitone enhanced the appearance in plasma of 25-hydroxycholecalciferol (peak IV on silicic acid chromatography), and of more-polar metabolites (peak V), but not of the most-polar metabolites (peak VI). Peak IV had the chromatographic properties of authentic 25-hydroxycholecalciferol (25-HCC) and had biological activity. 3. There was no effect on the appearance of peaks V and VI in plasma after an injection of radioactive 25-HCC. 4. Treatment with phenobarbitone enhanced the excretion of metabolites of radioactive vitamin D3 in bile. These metabolites were largely water-soluble conjugates of peaks IV, V and VI, which included glucuronides. Peak IV in bile was not identical with 25-HCC. 5. Prolonged treatment with phenobarbitone depleted the tissue radioactivity of rats given radioactive vitamin D3.

scholarly journals Assessment of Vitamin D Metabolism in Patients with Cushing’s Disease in Response to 150,000 IU Cholecalciferol Treatment

Nutrients ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 4329
Author(s):  
Alexandra Povaliaeva ◽  
Viktor Bogdanov ◽  
Ekaterina Pigarova ◽  
Artem Zhukov ◽  
Larisa Dzeranova ◽  
...  
Keyword(s):  
Vitamin D ◽  
Cushing’S Disease ◽  
Serum Vitamin ◽  
Urinary Free Cortisol ◽  
Cushing's Disease ◽  
Control Group ◽  
Vitamin D Metabolites ◽  
Vitamin D Metabolism ◽  
Serum Vitamin D ◽  
Free Cortisol

In this study we aimed to assess vitamin D metabolism in patients with Cushing’s disease (CD) compared to healthy individuals in the setting of bolus cholecalciferol treatment. The study group included 30 adults with active CD and the control group included 30 apparently healthy adults with similar age, sex and BMI. All participants received a single dose (150,000 IU) of cholecalciferol aqueous solution orally. Laboratory assessments including serum vitamin D metabolites (25(OH)D3, 25(OH)D2, 1,25(OH)2D3, 3-epi-25(OH)D3 and 24,25(OH)2D3), free 25(OH)D, vitamin D-binding protein (DBP) and parathyroid hormone (PTH) as well as serum and urine biochemical parameters were performed before the intake and on Days 1, 3 and 7 after the administration. All data were analyzed with non-parametric statistics. Patients with CD had similar to healthy controls 25(OH)D3 levels (p > 0.05) and higher 25(OH)D3/24,25(OH)2D3 ratios (p < 0.05) throughout the study. They also had lower baseline free 25(OH)D levels (p < 0.05) despite similar DBP levels (p > 0.05) and lower albumin levels (p < 0.05); 24-h urinary free cortisol showed significant correlation with baseline 25(OH)D3/24,25(OH)2D3 ratio (r = 0.36, p < 0.05). The increase in 25(OH)D3 after cholecalciferol intake was similar in obese and non-obese states and lacked correlation with BMI (p > 0.05) among patients with CD, as opposed to the control group. Overall, patients with CD have a consistently lower 25(OH)D3/24,25(OH)2D3 ratio, which is indicative of a decrease in 24-hydroxylase activity. This altered activity of the principal vitamin D catabolism might influence the effectiveness of cholecalciferol treatment. The observed difference in baseline free 25(OH)D levels is not entirely clear and requires further study.

scholarly journals The effect of disodium ethane-1-hydroxy-1,1-diphosphonate on the metabolism of calcitriol in chicks

1987 ◽  
Vol 243 (1) ◽  
pp. 75-78 ◽  
Author(s):  
C Lidor ◽  
M S Meyer ◽  
R H Wasserman ◽  
S Edelstein
Keyword(s):  
Vitamin D ◽  
Urinary Excretion ◽  
Intestinal Absorption ◽  
Binding Protein ◽  
Sole Source ◽  
Treated Group ◽  
Response To Treatment ◽  
Vitamin D Metabolism ◽  
Calbindin D28k ◽  
25 Hydroxycholecalciferol

Decreased intestinal absorption of Ca2+ occurs in response to treatment with disodium ethane-1-hydroxy-1,1-diphosphonate (EHDP). The effect is due to decreased 1-hydroxylation of calcidiol (25-hydroxycholecalciferol) in the kidney. In an attempt to establish whether impairment of vitamin D metabolism at steps beyond kidney hydroxylation occurs due to treatment with EHDP, chicks were depleted of vitamin D and were treated with calcitriol (1,25-dihydroxycholecalciferol) as their sole source of the vitamin. The chicks were then divided into two groups, one being treated with EHDP while the second group served as control. Intestinal absorption of Ca2+ in the EHDP-treated group was found to be impaired, along with decreases in concentrations of calbindin D28K (the 28,000-Mr vitamin D-dependent Ca2+-binding protein). When the chicks were dosed with [3H]calcitriol, significantly lower concentrations of the sterol were detected in the duodena of EHDP-treated birds. Measurement of levels of receptors for calcitriol in duodena showed no difference between groups, but levels of calcitriol in sera were considerably lower in the EHDP-treated group along with the elevated biliary and urinary excretion of glucuronidated conjugates. It is therefore concluded that treatment with EHDP results in increased catabolism of calcitriol in addition to the known suppression of the renal production of the hormone.

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