scholarly journals Metabolism of vitamin D. A new cholecalciferol metabolite, involving loss of hydrogen at C-1, in chick intestinal nuclei

1969 ◽  
Vol 115 (2) ◽  
pp. 269-277 ◽  
Author(s):  
D. E. M. Lawson ◽  
P. W. Wilson ◽  
E. Kodicek
Keyword(s):  
Vitamin D ◽  
Adipose Tissue ◽  
Maximum Concentration ◽  
Simultaneous Administration ◽  
Polar Material ◽  
Polar Metabolite ◽  
Chemical Structures ◽  
Intracellular Organelle ◽  
Liver And Kidney ◽  
25 Hydroxycholecalciferol

1. A comparison was made of the nature and intestinal intracellular distribution of the metabolites formed in vitamin D-deficient chicks from [4−14C]cholecalciferol and [1−3H]cholecalciferol. 2. The simultaneous administration of the two radioactive substances showed the presence in blood, liver, intestine, kidney and bone of cholecalciferol, its ester, 25-hydroxycholecalciferol and a further metabolite of cholecalciferol more polar than 25-hydroxycholecalciferol. The 3H/14C ratios in these four radioactive components were the same as that of the dosed material (4·7:1) with the exception of the most polar material. The 3H/14C ratio was lower in the fourth, most polar, metabolite (0·4:1–1·8:1) in all tissues examined, with the exception of blood. 3. In the chick intestine the polar metabolite accounted for almost 70% of the radioactivity in this tissue after a dose of 0·5μg. of [4−14C,1−3H]cholecalciferol. This polar metabolite from the intestine also had the lowest 3H/14C ratio of all the tissues. It appears that in the chick intestine the polar metabolite reaches a maximum concentration of 1ng./g. of tissue, above which it cannot be increased irrespective of the dose of the vitamin. 4. The intestinal intracellular organelle with the highest concentration of 14C radioactivity is the nucleus, and this radioactivity is almost entirely due to the polar metabolite with the lowered 3H/14C ratio, in this case <0·2:1. It appears to be further localized in the chromatin of the nuclei. However, about half of the polar metabolite in the intestine is extranuclear. 5. Double-labelled 25-hydroxycholecalciferol was prepared and after its administration to vitamin D-deficient chicks the polar metabolite with the lowered 3H/14C ratio was detected in liver, kidney, intestine, bone, muscle and heart. 6. None of the polar metabolite with the lowered 3H/14C ratio was detected 16hr. after dosing with either the double-labelled vitamin or the double-labelled 25-hydroxycholecalciferol in blood and adipose tissue of vitamin D-deficient chicks, nor in the intestine, liver and kidney of supplemented birds. 7. The reasons for this loss of 3H relative to 14C are discussed in relation to possible chemical structures of this new polar metabolite.

scholarly journals Interrelationships in rats of tissue pools of cholecalciferol and 25-hydroxycholecalciferol formed in u.v. light

1986 ◽  
Vol 233 (2) ◽  
pp. 535-540 ◽  
Author(s):  
D E M Lawson ◽  
S H Sedrani ◽  
J Douglas
Keyword(s):  
Vitamin D ◽  
Adipose Tissue ◽  
Compartment Model ◽  
Volume Of Distribution ◽  
High Rate ◽  
Pharmacokinetic Analysis ◽  
Rat Skin ◽  
Small Rise ◽  
Rat Adipose Tissue ◽  
25 Hydroxycholecalciferol

Vitamin D-deficient rats were irradiated with u.v. light three times weekly for 30 min for several weeks. D3 (cholecalciferol) and 25(OH)D3 (25-hydroxycholecalciferol) concentrations in skin, plasma, muscle and adipose tissue were measured. In other experiments, isolated skin or the whole animal was irradiated once and the cholecalciferol response monitored. Only a small fraction of the 7-dehydrocholesterol in skin is converted into D3 (less than 2%), and the presence of fur decreases the proportion converted into 20% of that occurring in shaved rat skin. D3 formed in the skin disappears relatively slowly, so that about 90% has gone after 7 days. In normal rats 10 micrograms of D3 formed over 2 h irradiation only caused a small rise in plasma D3 concentration over the following week, indicative of a high rate of clearance from this tissue. Irradiation of vitamin D-deficient rats for a prolonged period raised plasma D3 and 25(OH)D3 concentrations to a constant value. D3, but not 25(OH)D3, could be found in adipose tissue and muscle. Prolonged irradiation of normal rats showed these tissues and plasma could hold very large amounts of D3. Pharmacokinetic analysis of the changes in D3 concentration in rats showed that the disposition kinetics of D3 was explained by a two-compartment model with half-lives of 13.8 and 7.7 days. The volume of distribution of the more-slowly-turning-over compartment was 500 ml, which presumably reflects the large amounts of D3 that can accumulate in adipose tissue. Rat skin can synthesize about 0.85 ng of D3/mJ of u.v. light energy, but it seems that not all this is available to the rat. Adipose-tissue D3 is available for use by the rat, the t1/2 being 12.0 days.

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.

Insulin Sensitizing Effects of Vitamin D Mediated through Reduced Adipose Tissue Inflammation and Fibrosis

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 39-OR
Author(s):  
ERIC LONTCHI-YIMAGOU ◽  
SONA KANG ◽  
KEHAO ZHANG ◽  
AKANKASHA GOYAL ◽  
JEE YOUNG YOU ◽  
...  
Keyword(s):  
Vitamin D ◽  
Adipose Tissue ◽  
Adipose Tissue Inflammation ◽  
Tissue Inflammation

Adipose Tissue Remodeling by Prolonged Administration of High Dose of Vitamin D3 in Rats Treated to Prevent Sarcopenia

2017 ◽  
Vol 68 (9) ◽  
pp. 2139-2143 ◽  
Author(s):  
Alin Constantin Pinzariu ◽  
Sorin Aurelian Pasca ◽  
Allia Sindilar ◽  
Cristian Drochioi ◽  
Mihail Balan ◽  
...  
Keyword(s):  
Vitamin D ◽  
Adipose Tissue ◽  
Vitamin D3 ◽  
Term Treatment ◽  
High Dose ◽  
Omental Adipose Tissue ◽  
Long Term Treatment ◽  
Male Wistar Rats ◽  
Adipose Tissue Remodeling ◽  
Visceral Adipose

To examine the effect of high dose vitamin D3 treatment on visceral adipose tissue, we used vitamin D deficient male Wistar rats (18 months old) as a model of sarcopenia. The aging process is not only responsive for the losing muscle mass but also for redistribution of lipid resulting in altered fatty acid storage and dysdifferentiation of mesenchymal precursors. The effect of aging and vitamin D treatment (weekly oral gavage with 0.125 mg vitamin D3 (5000 IU)/100g body weight) on the omental adipose tissue were histological examinated. At the end of the experiment (9 monhs), adaptive changes to the reduction of adipogenesis and increased apoptosis in response to long-term treatment with vitamin D consisted of smaller size of adipocyte and moderate macrophage infiltrate.

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.

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