1α, 25-Dihydroxyvitamin D3 enables regenerating liver cells to make functional ribonucleotide reductase subunits and replicate DNA in thyroparathyroidectomized rats

1985 ◽  
Vol 63 (5) ◽  
pp. 319-324 ◽  
Author(s):  
T. Youdale ◽  
J. F. Whitfield ◽  
R. H. Rixon
Keyword(s):  
Body Weight ◽  
Dna Replication ◽  
Ribonucleotide Reductase ◽  
Intraperitoneal Injection ◽  
Liver Cells ◽  
Regenerating Liver ◽  
Dihydroxyvitamin D3 ◽  
Dihydroxyvitamin D ◽  
Do So

Between 16 and 20 h after partial (70%) hepatectomy (HPX) in normal rats, the remaining liver cells accumulate ribonucleotide reductase subunits, assemble these into active holoenzyme, and initiate DNA replication. These late prereplicative activities did not occur in most of the liver cells remaining after HPX in rats which had been thyroparathyroidectomized (TPTX) 72 h previously. However, one intraperitoneal injection of 400 or 600 ng 1α, 25-dihydroxyvitamin D3/100 g body weight at the time of HPX enabled the remaining liver cells in such TPTX rats to make functional ribonucleotide reductase subunits, assemble these subunits into active CDP-reducing holoenzymes, and replicate their DNA, though they started to do so 4 to 16 h later than in normal animals.

Changes in the cytoplasmic and nuclear activities of the ribonucleotide reductase holoenzyme and its subunits in regenerating liver cells in normal and thyroparathyroidectomized rats

1984 ◽  
Vol 62 (9) ◽  
pp. 914-919 ◽  
Author(s):  
T. Youdale ◽  
L. Frappier ◽  
J. F. Whitfield ◽  
R. H. Rixon
Keyword(s):  
Dna Synthesis ◽  
Ribonucleotide Reductase ◽  
Maximum Level ◽  
Liver Cells ◽  
Synthetic Activity ◽  
Regenerating Liver ◽  
Nuclear Level ◽  
Rat Liver Cells ◽  
Specific Effector ◽  
High Level

The level of the cytoplasmic ribonucleotide reductase nonheme-iron-containing L2 subunit in regenerating rat liver cells began rising about 2 h before the onset of DNA synthesis, rose sharply to a maximum level about 4 h before the DNA-synthetic activity reached its peak, and then stayed at this high level even after the cells had finished replicating their DNA. The cytoplasmic level of the CDP-specific, effector-binding L1 subunit and the holoenzyme activity began rising together about 2 h after the L2 subunit began increasing and at the same time as the DNA-synthetic activity, but subsequently rose much more slowly than the L2 subunit and continued rising even after the cells had finished making DNA. The nuclear level of the L2 subunit did not rise in the regenerating liver cells, but the nuclear level of the L1 subunit and the holoenzyme activity began rising together about the same time as the DNA-synthetic activity, peaked briefly 4–6 h before the peak DNA-synthetic activity, and dropped sharply back to the basal levels by the time the DNA-synthetic activity reached its peak, but then rose again slowly as the cells finished making DNA. Thyroparathyroidectomy 72 h before partial hepatectomy prevented the cytoplasmic and nuclear subunits and holoenzyme activity from rising and prevented most of the remaining liver cells from initiating DNA synthesis.

The Morphology of Vacuolated Cells in the Liver Following Administration of Vitamin A.

1973 ◽  
Vol 31 ◽  
pp. 408-409
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo ◽  
Fawzia Batti
Keyword(s):  
Electron Microscopy ◽  
Body Weight ◽  
Vitamin A ◽  
Light And Electron Microscopy ◽  
Liver Cells ◽  
Prominent Feature ◽  
Vascular Space ◽  
Vacuolated Cell ◽  
Vacuolated Cells ◽  
Vacuolated Cytoplasm

Vacuolated cells in the liver of young rats were studied by light and electron microscopy following the administration of vitamin A (200 units per gram of body weight). Their characteristics were compared with similar cells found in untreated animals.In rats given vitamin A, cells with vacuolated cytoplasm were a prominent feature. These cells were found mostly in a perisinusoidal location, although some appeared to be in between liver cells (Fig. 1). Electron microscopy confirmed their location in Disse's space adjacent to the sinusoid and in recesses between liver cells. Some appeared to be bordering the lumen of the sinusoid, but careful observation usually revealed a tenuous endothelial process separating the vacuolated cell from the vascular space. In appropriate sections, fenestrations in the thin endothelial processes were noted (Fig. 2, arrow).

Differential regulation of PHEX expression in bone and parathyroid gland by chronic renal insufficiency and 1,25-dihydroxyvitamin D3

2004 ◽  
Vol 286 (4) ◽  
pp. F739-F748 ◽  
Author(s):  
Angela J. Brewer ◽  
Lucie Canaff ◽  
Geoffrey N. Hendy ◽  
Harriet S. Tenenhouse
Keyword(s):  
Renal Insufficiency ◽  
Parathyroid Gland ◽  
Chronic Renal Insufficiency ◽  
Control Diet ◽  
Protein Abundance ◽  
Dihydroxyvitamin D3 ◽  
Dihydroxyvitamin D ◽  
Phex Gene ◽  
Rat Tibia ◽  
Serum Pth

Mutations in the PHEX gene are responsible for X-linked hypophosphatemia, a renal phosphate-wasting disorder associated with defective skeletal mineralization. PHEX is predominantly expressed in bones and teeth and in the parathyroid gland of patients with chronic renal failure and tertiary hyperparathyroidism. The purpose of the present study was to examine the effects of renal insufficiency and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] on the regulation of PHEX expression in rat tibia and parathyroid gland. In rats fed a high-phosphate (Pi) diet, ⅚ nephrectomy elicited a significant increase in the serum parathyroid hormone (PTH) concentration that was associated with a significant increase in the abundance of PHEX mRNA and protein in the tibia and a significant increase in PHEX mRNA in the parathyroid gland. In contrast, 1,25(OH)2D3 administration to intact rats fed a control diet elicited a significant decrease in the serum PTH concentration that was accompanied by a significant decrease in PHEX mRNA and protein abundance in the tibia and a significant decrease in PHEX mRNA in the parathyroid gland. In addition, the increases in serum PTH levels and PHEX mRNA in the tibia and parathyroid gland in ⅚ nephrectomized rats fed a high-Pi diet were blunted by 1,25(OH)2D3. Serum PTH concentration was positively and significantly correlated with tibial PHEX mRNA and protein abundance. In summary, we demonstrate that PHEX expression in the tibia and parathyroid gland is increased by chronic renal insufficiency and decreased by 1,25(OH)2D3 administration and suggest that PTH status may play an important role in mediating these changes in PHEX expression.

Regulation of apoptosis in adipocytes and breast cancer cells by 1,25-dihydroxyvitamin D3: a link between obesity and breast cancer

2013 ◽  
Vol 14 (3) ◽  
Author(s):  
Igor N. Sergeev
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Mammary Cancer ◽  
Tissue Mass ◽  
Dihydroxyvitamin D3 ◽  
Dihydroxyvitamin D ◽  
Promising Strategy ◽  
Adipose Tissue Mass

AbstractModulation of apoptosis is emerging as a promising strategy for prevention and treatment of breast cancer and obesity because removal of mammary cancer cells and mature adipocytes through this process will result in decreasing tumor size and produce long-term reduction in adipose tissue mass. The hormone 1,25-dihydroxyvitamin D

scholarly journals 1,25-Dihydroxyvitamin D3 and Development of Tuberculosis in Cattle

2003 ◽  
Vol 10 (6) ◽  
pp. 1129-1135 ◽  
Author(s):  
S. G. Rhodes ◽  
L. A. Terry ◽  
J. Hope ◽  
R. G. Hewinson ◽  
H. M. Vordermeier
Keyword(s):  
Vitamin D ◽  
T Cell ◽  
Mononuclear Cells ◽  
T Cell Proliferation ◽  
Accessory Cell ◽  
Dihydroxyvitamin D3 ◽  
Dihydroxyvitamin D ◽  
Cell Responses ◽  
1,25 Dihydroxyvitamin D ◽  
Accessory Cells

ABSTRACT This report describes the presence and activity of 1,25-dihydroxyvitamin D3 (1,25-D3) in experimental bovine tuberculosis. Animals that went on to develop tuberculous lesions exhibited a rapid transient increase in serum 1,25-D3 within the first 2 weeks following infection with Mycobacterium bovis. 1,25-D3-positive mononuclear cells were later identified in all tuberculous granulomas by immunohistochemical staining of postmortem lymph node tissue. These results suggest a role for 1,25-D3 both at the onset of infection and in the development of the granuloma in these infected animals. Using a monoclonal antibody to the vitamin D receptor (VDR) as a VDR agonist, we confirmed that activation of the vitamin D pathway profoundly depresses antigen-specific, but not mitogenic, bovine peripheral blood T-cell responses (proliferation and gamma interferon production). Investigation of the mechanism of this suppression showed that the VDR antibody modified the expression of CD80 by accessory cells, such that a significant positive correlation between T-cell proliferation and accessory cell CD80 emerged.

The endoplasmic reticulum in regenerating liver cells

1985 ◽  
Vol 240 (1) ◽  
Author(s):  
Lillemor Lewan ◽  
Hadar Emanuelsson
Keyword(s):  
Endoplasmic Reticulum ◽  
Liver Cells ◽  
Regenerating Liver

Specific estimation of 24,25-dihydroxyvitamin D in plasma by gas chromatography-mass spectrometry.

1984 ◽  
Vol 30 (7) ◽  
pp. 1193-1198 ◽  
Author(s):  
R D Coldwell ◽  
D J Trafford ◽  
H L Makin ◽  
M J Varley ◽  
D N Kirk
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
Plasma Vitamin ◽  
Vitamin D Metabolites ◽  
Dihydroxyvitamin D3 ◽  
Dihydroxyvitamin D ◽  
Chromatography Mass Spectrometry ◽  
24,25 Dihydroxyvitamin D3

Abstract This paper describes a specific mass-fragmentographic method, involving a stable-isotope-labeled internal standard, for measurement of 24,25-dihydroxyvitamin D in human plasma. Vitamin D metabolites were rapidly extracted from plasma by using Sep-Pak C18 cartridges and separated into fractions on Sep-Pak SIL cartridges. The polar fraction, containing the dihydroxylated metabolites, was further purified by "high-performance" liquid chromatography on Zorbax SIL. The fraction containing 24,25-dihydroxyvitamin D was collected, evaporated, and converted to the 24:25-cyclic n-butyl boronate-3-trimethylsilyl ether derivative before analysis by gas chromatography-mass spectrometry. The intensity of the mass fragment (m/z 449, m/z 455 for the hexadeuterated internal standard) arising from the loss of one of the angular methyls and the 3-silanol group [( M-90-15]+) was monitored. The minimum limit of detection for this method is about 0.1 microgram/L. Inter- and intra-assay reproducibility was acceptable, and analytical recovery of added 24,25-dihydroxyvitamin D3 over the concentration range 1.0 to 5.0 micrograms/L was quantitative. Concentrations of 24,25-dihydroxyvitamin D3 in plasma of 21 apparently healthy volunteers were between 0.55 and 5.39 micrograms/L, higher values being obtained after prolonged exposure to the sun. No 24,25-dihydroxyvitamin D2 could be detected in any plasma sample examined.

Ribonucleotide reductase from Fusarium oxysporum does not Respond to DNA replication stress

DNA Repair ◽  
2019 ◽  
Vol 83 ◽  
pp. 102674 ◽  
Author(s):  
Rotem Cohen ◽  
Shira Milo ◽  
Sushma Sharma ◽  
Alon Savidor ◽  
Shay Covo
Keyword(s):  
Dna Replication ◽  
Fusarium Oxysporum ◽  
Ribonucleotide Reductase ◽  
Replication Stress ◽  
Dna Replication Stress
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