Absence of renal 25-hydroxycholecalciferol-1-hydroxylase activity in a pig strain with vitamin D-dependent rickets

1986 ◽  
Vol 38 (2) ◽  
pp. 87-94 ◽  
Author(s):  
I. Winkler ◽  
F. Schreiner ◽  
J. Harmeyer
Keyword(s):  
Vitamin D ◽  
Hydroxylase Activity ◽  
25 Hydroxycholecalciferol

scholarly journals Effect of oestrogen and 1,25-dihydroxycholecalciferol on 25-hydroxycholecalciferol metabolism in primary chick kidney-cell cultures

1978 ◽  
Vol 174 (1) ◽  
pp. 231-236 ◽  
Author(s):  
E Spanos ◽  
D I Barrett ◽  
K T Chong ◽  
I MacIntyre
Keyword(s):  
Vitamin D ◽  
Cell Cultures ◽  
Kidney Cell ◽  
Primary Cultures ◽  
Kidney Cells ◽  
Hydroxylase Activity ◽  
Experimental Conditions ◽  
Polar Metabolites ◽  
Chick Kidney ◽  
25 Hydroxycholecalciferol

Primary cultures of chick kidney cells convert 25-hydroxycholecalciferol into more-polar metabolites. Cells from vitamin D-deficient chicks have high 25-hydroxycholecalciferol 1 alpha-hydroxylase (1 alpha-hydroxylase) activity, but no 25-hydroxycholecalciferol 24-hydroxylase (24-hydroxylase) activity. Physiological concentrations of 1,25-dihydroxycholeclaciferol suppress 1 alpha-hydroxylase and induce 24-hydroxylase activity. The inhibition of 1 alpha-hydroxylase preceded the induction of 24-hydroxylase. In contrast, oestradiol-17 beta had no effect on the activity of either hydroxylase under a variety of experimental conditions. These results clearly demonstrate that 1,25-dihydroxycholecalciferol, but not oestrogen, acts directly on the kidney cells to regulate the metabolism of 25-hydroxycholecalciferol.

Submitochondrial localization of kidney 25-hydroxycholecalciferol 1α-hydroxylase in vitamin D repleted weanling guinea pigs

1987 ◽  
Vol 65 (7) ◽  
pp. 673-676 ◽  
Author(s):  
Xue Yan ◽  
Guy Charette ◽  
Edgard E. Delvin
Keyword(s):  
Vitamin D ◽  
Cytochrome C ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Membrane Fraction ◽  
Hydroxylase Activity ◽  
Oxidoreductase Activity ◽  
Pig Kidney ◽  
Steroid Hydroxylases ◽  
25 Hydroxycholecalciferol

We have studied the submitochondrial localization of guinea-pig kidney 25-hydroxycholecalciferol 1α-hydroxylase. Treatment of the mitochondrial-enriched fraction with recrystallized digitonin produced mitoplasts bordered by a single membrane and with intact matrix. They contained nearly 90% of the 25-hydroxycholecalciferol 1α-hydroxylase activity and nearly 100% of the cytochrome-c: oxygen oxidoreductase. Amine: oxygen oxidoreductase activity remained mainly in the outer membrane fraction. These data show that 25-hydroxycholecalciferol 1α-hydroxylase has a distribution similar to that of steroid hydroxylases.

The effect of dietary calcium on the activity of 25-hydroxycholecalciferol-l-hydroxylase and Ca absorption in vitamin D-replete chicks

1977 ◽  
Vol 38 (1) ◽  
pp. 47-54 ◽  
Author(s):  
R. Swaminathan ◽  
Barbara A. Sommerville ◽  
A. D. Care
Keyword(s):  
Vitamin D ◽  
Dietary Intake ◽  
Specific Activity ◽  
Dietary Calcium ◽  
Duodenal Mucosa ◽  
List Type ◽  
Type Number ◽  
Hydroxylase Activity ◽  
Dietary Level ◽  
25 Hydroxycholecalciferol

1.As most of the studies on the regulation of renal 25-hydroxycholecalciferol-1-hydroxylase (25-HCC-1-hydroxylase) activity have been done in marginally-vitamin D-defieient animals and as it is known that vitamin D administration suppresses the specific activity of the 25-HCC-1-hydroxylase, it was decided to study the effect of dietary calcium on the activity of 25-HCC-1-hydroxylase and on Ca absorption in vitamin Dreplete chicks.2.Chicks, 10 d old, were given diets differing in their Ca contents (65 nmol cholecalciferol/kg diet) for 10 d and the activity of 25-HCC-1-hydroxylase in kidney homogenates, Ca absorption from the duodenum, Cabinding protein (CaBP) activity in the duodenal mucosa and plasma Ca and phosphate concentrations were all determined.3.The CaBP activity and the efficiency of Ca absorption both decreased with increasing dietary intake of Ca. Ca absorption and CaBP activity were significantly correlated (r 0.995, P < 0.01).4.The activity of 25-HCC-1-hydroxylase decreased as the dietary level of Ca increased and was significantly correlated with Ca absorption (r0.900, P < 005). The plasma Ca concentration and the activity of 25-HCC-1-hydroxylase were inversely related (r-0.940, P < 0.01).5.It is concluded that in the vitamin D-replete chick the efficiency of duodenal Ca absorption is regulated by the renal 25-HCC-1-hydroxylase activity via production of 1,25-dihydroxycholecalciferol and CaBP synthesis.

Feedback Regulation of 25-Hydroxycholecalciferol Metabolism by Vitamin D3

1975 ◽  
Vol 48 (3) ◽  
pp. 227-230
Author(s):  
I. M. A. Evans ◽  
K. W. Colston ◽  
L. Galante ◽  
I. MacIntyre
Keyword(s):  
Vitamin D ◽  
Vitamin D3 ◽  
Actinomycin D ◽  
Feedback Regulation ◽  
Kidney Cells ◽  
Hydroxylase Activity ◽  
25 Hydroxycholecalciferol

1. In vitamin D-deficient chicks both vitamin D3 and 1α-hydroxycholecalciferol markedly decrease renal 1-hydroxylase activity and induce 24-hydroxylase activity. 2. Actinomycin D abolishes both effects. 3. These results are consistent with feedback regulation of vitamin D3 metabolism by a direct nuclear action of the vitamin or its metabolites on the kidney cells.

24-Hydroxylase: potential key regulator in hypervitaminosis D3in growing dogs

2003 ◽  
Vol 284 (3) ◽  
pp. E505-E513 ◽  
Author(s):  
M. A. Tryfonidou ◽  
M. A. Oosterlaken-Dijksterhuis ◽  
J. A. Mol ◽  
T. S. G. A. M. van den Ingh ◽  
W. E. van den Brom ◽  
...  
Keyword(s):  
Gene Expression ◽  
Vitamin D ◽  
Parathyroid Hormone ◽  
Plasma Levels ◽  
Control Group ◽  
Metabolic Clearance ◽  
Hydroxylase Activity ◽  
Hydroxylase Gene ◽  
Increased Sensitivity ◽  
25 Hydroxycholecalciferol

A group of growing dogs supplemented with cholecalciferol (vitamin D3; HVitD) was studied vs. a control group (CVitD; 54,000 vs. 470 IU vitamin D3/kg diet, respectively) from 3 to 21 wk of age. There were no differences in plasma levels of Piand growth-regulating hormones between groups and no signs of vitamin D3intoxication in HVitD. For the duration of the study in HVitD vs. CVitD, plasma 25-hydroxycholecalciferol levels increased 30- to 75-fold; plasma 24,25-dihydroxycholecalciferol levels increased 12- to 16-fold and were accompanied by increased renal 24-hydroxylase gene expression, indicating increased renal 24-hydroxylase activity. Although the synthesis of 1,25-dihydroxycholecalciferol [1,25(OH)2D3] was increased in HVitD vs. CVitD (demonstrated by [3H]1,25(OH)2D3and increased renal 1α-hydroxylase gene expression), plasma 1,25(OH)2D3levels decreased by 40% as a result of the even more increased metabolic clearance of 1,25(OH)2D3(demonstrated by [3H]1,25(OH)2D3and increased gene expression of intestinal and renal 24-hydroxylase). A shift of the Ca set point for parathyroid hormone to the left indicated increased sensitivity of the chief cells. Effective counterbalance was provided by hypoparathyroidism, hypercalcitoninism, and the key regulator 24-hydroxylase, preventing the development of vitamin D3toxicosis.

scholarly journals 25-Hydroxycholecalciferol Concentration Is Associated with Protein Loss and Serum Albumin Level during the Acute Phase of Burn Injury

Nutrients ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2780
Author(s):  
Andrzej Krajewski ◽  
Krzysztof Piorun ◽  
Dominika Maciejewska-Markiewicz ◽  
Marta Markowska ◽  
Karolina Skonieczna-Żydecka ◽  
...  
Keyword(s):  
Vitamin D ◽  
Protein Concentration ◽  
Serum Albumin Level ◽  
Burn Injury ◽  
Albumin Level ◽  
Albumin Concentration ◽  
Transaminase Activity ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
25 Hydroxycholecalciferol

Background: Burned patients have an increased need for vitamin D supply related to the maintenance of calcium–phosphate homeostasis and the regulation of cell proliferation/differentiation. This study aimed to analyze the concentration of 25-hydroxycholecalciferol and its relationship with severe condition after burn injury. Methods: 126 patients were enrolled in the study. Patients were qualified due to thermal burns—over 10% of total body surface area. On the day of admission, the following parameters were assessed: 25-hydroxycholecalciferol concentration, total protein concentration, albumin concentration, aspartate transaminase activity, alanine transaminase activity, albumin concentration, creatinine concentration, c-reactive protein concentration, procalcitonin concentration, and interleukin-6 concentration. Results: Almost all patients (92%) in the study group had an improper level of vitamin D (<30 ng/mL), with the average of 11.6 ± 10.7 ng/mL; 17.5% of patients had levels of vitamin D below the limit of determination—under 3 ng/mL. The study showed that there are several factors which correlated with vitamin D concentration during the acute phase of burn injury, including: total protein (r = 0.42, p < 0.01), albumin, (r = 0.62, p < 0.01), percentage of body burns (r = 0.36, p < 0.05), aspartate aminotransferase (r = 0.21, p < 0.05), and c-reactive protein (r = 0.22, p < 0.05). We did not find any significant correlation between vitamin D concentration and body mass index. Conclusions: The burn injury has an enormous impact on the metabolism and the risk factors of the deficiency for the general population (BMI) have an effect on burned patients. Our study showed that concentration of 25-hydroxycholecalciferol is strongly correlated with serum albumin level, even more than total burn surface area and burn degrees as expected. We suspect that increased supplementation of vitamin D should be based on albumin level and last until albumin levels are balanced.

scholarly journals Impact of the 25-Hydroxycholecalciferol Concentration and Vitamin D Deficiency Treatment on Changes in the Bone Level at the Implant Site during the Process of Osseointegration: A Prospective, Randomized, Controlled Clinical Trial

2021 ◽  
Vol 10 (3) ◽  
pp. 526
Author(s):  
Jakub Kwiatek ◽  
Aleksandra Jaroń ◽  
Grzegorz Trybek
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Controlled Clinical Trial ◽  
Randomized Controlled ◽  
Group A ◽  
Bone Level ◽  
Group B ◽  
Implant Treatment ◽  
Correct Level ◽  
25 Hydroxycholecalciferol

Introduction: The most important factor which is responsible for the positive course of implant treatment is the process of osseointegration between the implant structure and the host’s bone tissue. The aim of this study was to assess what effect the 25-hydroxycholecalciferol concentration and vitamin D deficiency treatment have on changes in the bone level at the implant site during the process of osseointegration in the mandible. Materials and Methods: The study was with 122 people qualified for implant surgery, who were assigned to three research groups (A, B, and C). Laboratory, clinical, and radiological tests were performed on the day of surgery, and after 6 and 12 weeks. The bone level in the immediate proximity of the implant was determined by radiovisiography (RVG). Results: The bone level after 12 weeks in Groups B and C was significantly higher than after 6 weeks. The bone level in the study Group B was significantly higher than in Group A. The study showed that the higher the levels of 25-hydroxycholecalciferol were observed on the day of surgery, the higher was the level of bone surrounding the implant after 6 and 12 after surgery. Conclusion: The correct level of 25-hydroxycholecalciferol on the day of surgery and vitamin D deficiency treatment significantly increase the bone level at the implant site in the process of radiologically assessed osseointegration.

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