scholarly journals Differential Effect of Vitamin K and Vitamin D Supplementation on Bone Mass in Young Rats Fed Normal or Low Calcium Diet

2004 ◽  
Vol 45 (2) ◽  
pp. 314 ◽  
Author(s):  
Jun Iwamoto ◽  
Tsuyoshi Takeda ◽  
Shoichi Ichimura ◽  
Yoshihiro Sato ◽  
James K. Yeh
Keyword(s):  
Vitamin D ◽  
Bone Mass ◽  
Vitamin K ◽  
Differential Effect ◽  
Vitamin D Supplementation ◽  
Young Rats ◽  
Calcium Diet ◽  
Low Calcium Diet ◽  
Low Calcium

scholarly journals Intestinal Resistance to 1,25 Dihydroxyvitamin D in Mice Heterozygous for the Vitamin D Receptor Knockout Allele

Endocrinology ◽  
2007 ◽  
Vol 148 (3) ◽  
pp. 1396-1402 ◽  
Author(s):  
Yurong Song ◽  
James C. Fleet
Keyword(s):  
Vitamin D ◽  
Vitamin D Receptor ◽  
Time Course ◽  
Transient Receptor Potential ◽  
Gene Knockout ◽  
Mrna Levels ◽  
Wild Type ◽  
Calcium Diet ◽  
Low Calcium Diet ◽  
Low Calcium

We tested the hypothesis that low vitamin D receptor (VDR) level causes intestinal vitamin D resistance and intestinal calcium (Ca) malabsorption. To do so, we examined vitamin D regulated duodenal Ca absorption and gene expression [transient receptor potential channel, vallinoid subfamily member 6 (TRPV6), 24-hydroxylase, calbindin D9k (CaBP) mRNA, and CaBP protein] in wild-type mice and mice with reduced tissue VDR levels [i.e. heterozygotes for the VDR gene knockout (HT)]. Induction of 24-hydroxylase mRNA levels by 1,25 dihydroxyvitamin D3 [1,25(OH)2 D3] injection was significantly reduced in the duodenum and kidney of HT mice in both time-course and dose-response experiments. TRPV6 and CaBP mRNA levels in duodenum were significantly induced after 1,25(OH)2 D3 injection, but there was no difference in response between wild-type and HT mice. Feeding a low-calcium diet for 1 wk increased plasma PTH, renal 1α-hydroxylase (CYP27B1) mRNA level, and plasma 1,25(OH)2 D3, and this response was greater in HT mice (by 88, 55, and 37% higher, respectively). In contrast, duodenal TRPV6 and CaBP mRNA were not higher in HT mice fed the low-calcium diet. However, the response of duodenal Ca absorption and CaBP protein to increasing 1,25(OH)2 D3 levels was blunted by 40% in HT mice. Our data show that low VDR levels lead to resistance of intestinal Ca absorption to 1,25(OH)2 D3, and this resistance may be due to a role for the VDR (and VDR level) in the translation of CaBP.

Effect of Vitamin D Deficiency on Aminoaciduria and Intestinal Transport of Amino Acids in the Rat

1974 ◽  
Vol 52 (5) ◽  
pp. 972-977
Author(s):  
Claude L. Morin ◽  
Jean Léveillé ◽  
Victor Ling
Keyword(s):  
Amino Acids ◽  
Vitamin D ◽  
Secondary Hyperparathyroidism ◽  
Vitamin D Deficiency ◽  
Intestinal Transport ◽  
Calcium Content ◽  
Calcium Diet ◽  
Low Calcium Diet ◽  
Low Calcium ◽  
Normal Calcium

Generalized hyperaminoaciduria and hyperphosphaturia are associated with human vitamin D deficiency rickets and the effect has been reproduced in animals. The basis for the renal transport impairment was attributed to secondary hyperparathyroidism resulting from hypocalcemia.In this study we attempted over a 16-week period to induce hyperaminoaciduria in Holtzman rats with vitamin D deficient diets of varying calcium content (0.4% and 0.04%) so as to investigate the possibility of a concomitant defect in intestinal transport of amino acids. Despite signs of secondary hyperparathyroidism, generalized hyperaminoaciduria was not in evidence in any of the groups. However, increased urinary excretion of lysine and taurine was demonstrated in rats fed a low calcium diet without vitamin D (LCa−D). The same observation was also made for taurine in rats deprived of vitamin D and on a normal calcium diet (NCa−D) and in animals fed a low calcium diet with vitamin D (LCa+D). The results failed to show any effect of vitamin D deficiency, hypocalcemia, or secondary hyperparathyroidism on the intestinal transport of lysine, alanine, and cycloleucine.

Comparative effects of vitamin K and vitamin D supplementation on prevention of osteopenia in calcium-deficient young rats

Bone ◽  
2003 ◽  
Vol 33 (4) ◽  
pp. 557-566 ◽  
Author(s):  
J Iwamoto ◽  
J.K Yeh ◽  
T Takeda ◽  
S Ichimura ◽  
Y Sato
Keyword(s):  
Vitamin D ◽  
Vitamin K ◽  
Vitamin D Supplementation ◽  
Young Rats

Effect of Oophorectomy and Calcium Deprivation on Bone Mass in the Rat

1978 ◽  
Vol 54 (4) ◽  
pp. 439-446 ◽  
Author(s):  
A. Hodgkinson ◽  
Jean E. Aaron ◽  
A. Horsman ◽  
M. S. F. McLachlan ◽  
B. E. C. Nordin
Keyword(s):  
Bone Mass ◽  
Trabecular Bone ◽  
Dry Weight ◽  
Calcium Deficiency ◽  
Normal Diet ◽  
Female Rats ◽  
Cross Sectional ◽  
Calcium Diet ◽  
Low Calcium Diet ◽  
Low Calcium

1. The effects of a low calcium diet and of oophorectomy, separately and together, on cortical and trabecular bone mass, have been examined in mature female rats. 2. Calcium deprivation caused a significant decrease of weight, cortical cross-sectional area and ratio of cortical to total area in the femur, it significantly reduced the volume of trabecular bone and increased the percentage of osteoid surface in the tail vertebrae, and in addition increased the urinary excretion of phosphate and, initially, of hydroxyproline. 3. Oophorectomy caused similar though smaller changes in trabecular bone and urine, whereas the effects of oophorectomy on cortical bone were greater on a low calcium intake than on a normal intake. 4. The ash weight of the femora, expressed as a percentage of the total dry weight, was unaffected by calcium deprivation or oophorectomy alone but was significantly reduced when the two occurred together. 5. The percentage of resorption surfaces in the vertebrae tended to increase on the low calcium diet and after oophorectomy on the normal diet but decreased after oophorectomy on a low calcium diet. 6. It is concluded that oophorectomy and calcium deficiency each reduce bone mass in the adult rat but the greatest effect is seen when they are combined.

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