Effect of calcium stress on the skeleton mass of intact and ovariectomized rats

Geng, W.; DeMoss, Daniel; Wright, Gary L.

doi:10.1016/s0024-3205(00)00562-2

Cited by 21 publications

(16 citation statements)

References 24 publications

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“…In the present study, calcium intake varied between the groups. A high calcium intake has earlier been shown to prevent from ovariectomy-induced bone loss compared to a low calcium intake (2,300 mg vs. 200 mg/100 g and 1,000 mg vs. 20 mg/100 g) [23,24] . However, studies using a smaller range of calcium (1,500 mg vs. 660 mg/100 g, and 1,000 mg vs. 200 mg/100 g) do not show an effect on bone mineral density in OVX rats [12,25] .…”

Section: Discussionmentioning

confidence: 99%

Effects of Bioactive Peptide, Valyl-Prolyl-Proline (VPP), and <i>Lactobacillus helveticus</i> Fermented Milk Containing VPP on Bone Loss in Ovariectomized Rats

et al. 2007

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Background: Valyl-prolyl-proline (VPP), a bioactive peptide formed during the fermentation with Lactobacillus helveticus LBK-16H (L. helveticus), has been shown to increase bone formation in vitro. The aim of the study was to determine whether VPP and L. helveticus fermented milk prevent bone loss in ovariectomized (OVX) rats. Methods: During the 12-week intervention study, the OVX rats received VPP in water or L. helveticus fermented milk, containing VPP. Sham-operated rats receiving water acted as controls. The trabecular and cortical bone mineral density were determined by peripheral quantitative computed tomography before the operation and at 4 and 12 weeks. The mechanical testing and ash weight analysis as well as the static and dynamic histomorphometrical parameters were assessed at the end of the intervention. Results: VPP given in water showed no clear effect on bone loss. L. helveticus fermented milk prevented bone loss by decreasing bone turnover and increasing the bone mineral density. Ovariectomycaused a 57% loss in the trabecular bone, which was attenuated by 16% in the L. helveticus group. Conclusions: VPP peptide did not prevent ovariectomy-induced bone loss, which could be due to the poor bioavailability of VPP from water solution. L. helveticus fermented milk prevented bone loss, whether this is due to the VPP peptide cannot be concluded.

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Section: Discussionmentioning

confidence: 99%

Effects of Bioactive Peptide, Valyl-Prolyl-Proline (VPP), and <i>Lactobacillus helveticus</i> Fermented Milk Containing VPP on Bone Loss in Ovariectomized Rats

et al. 2007

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“…Estrogen deficiency causes postmenopausal osteoporosis through an increase in bone turnover that results in bone loss (20,37). In addition, recent reports that estrogen plays an important role in regulating intestinal Ca absorption suggest that estrogen deficiency also contributes to the pathogenesis of age-related osteoporosis (38,39).…”

Section: Discussionmentioning

confidence: 99%

Ovariectomy worsens secondary hyperparathyroidism in mature rats during low-Ca diet

Zhang¹,

Lai

et al. 2007

American Journal of Physiology-Endocrinology and Metabolism

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Zhang Y, Lai W-P, Wu C-F, Favus MJ, Leung P-C, Wong M-S. Ovariectomy worsens secondary hyperparathyroidism in mature rats during low-Ca diet. Am J Physiol Endocrinol Metab 292: E723-E731, 2007. First published October 31, 2006; doi:10.1152/ajpendo.00445.2006.-Estrogen deficiency impairs intestinal Ca absorption and induces bone loss, but its effects on the vitamin D-endocrine system are unclear. In the present study, calciotropic hormones levels, renal vitamin D metabolism, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]-dependent intestinal calcium absorption, and bone properties in 3-mo-old sham-operated (sham) or ovariectomized (OVX) rats fed either a normal-Ca (NCD; 0.6% Ca, 0.65% P) or a low-Ca (LCD; 0.1% Ca, 0.65% P) diet for 2 wk were determined. LCD increased serum 1,25(OH)2D3 levels in both sham and OVX rats. Serum parathyroid hormone [PTH(1-84)] levels were highest in OVX rats fed LCD. Renal 25-hydroxyvitamin D1␣-hydroxylase (1-OHase) protein expression was induced in both sham and OVX rats during LCD, while renal 1-OHase mRNA expression was highest in OVX rats fed LCD. Renal vitamin D receptor (VDR) and mRNA expressions in rats were induced by ovariectomy in rats fed NCD but suppressed by ovariectomy in rats fed LCD. The induction of intestinal calcium transporter-1 and calbindin-D9k mRNA expressions by LCD were not altered by ovariectomy. As expected, bone Ca content, cancellous bone mineral density, and bone strength index in proximal metaphysis of rat tibia were reduced by both ovariectomy and LCD (P Ͻ 0.05) as analyzed by two-way ANOVA. Taken together, the data demonstrate that ovariectomy alters the responses of circulating PTH levels, renal 1-OHase mRNA expression, and renal VDR expression to LCD. These results suggest that estrogen is necessary for the full adaptive response to LCD mediated by both PTH and 1,25(OH)2D3. parathyroid hormone ; renal vitamin D receptor; renal 25-hydroxyvitamin D1␣-hydroxylase; dietary Ca restriction THE IMPAIRMENT OF INTESTINAL Ca absorption in humans (19,23,35,39) and in rats (2, 9, 26, 29) and induction of bone turnover (1,15,30) by estrogen deficiency are believed to contribute to negative Ca balance and bone loss during menopause. The cause of the impairment of intestinal Ca absorption by estrogen deficiency has been attributed to either a decrease in serum 1,25-dihydroxyvitamin D 3 [1,25(OH) 2 D 3 ] levels (9, 16, 39) or a direct effect of estrogen on intestinal Ca transport (3,9,14,26). During menopause, the increased Ca requirements due to poor intestinal absorption and increased urinary loss are complicated by the age-related abnormalities of the vitamin Dendocrine system, including secondary hyperparathyroidism, intestinal resistance to 1,25(OH) 2 D 3 , and decreased 1,25(OH) 2 D 3 production due to impaired 25-hydroxyvitamin D1␣-hydroxylase (1-OHase) activity (37,38). Although the effects of menopause and estrogen on circulating levels of 1,25(OH) 2 D 3 in postmenopausal women have been reported (13,36), it is still unclear whether estrogen deficiency interferes ...

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“…Furthermore, if we adjust BMC to the muscle mass, the differences were not significant, suggesting that whole-body muscle mass has brought about a positive effect on whole-body BMC, but not on tibial and vertebral sites. Another suggestion, which was made by Geng et al, is that the deterioration of bone structure and mechanical integrity may not be attributed to overt loss in total bone mass, but rather involve a redistribution of bone mass (10). The changes are obviously site-specific, and might be balanced between axial and appendicular skeletal regions.…”

Section: Discussionmentioning

confidence: 99%

Alteration of Trabecular Bone under Chronic β2 Agonists Treatment

Bonnet

Brunet-Imbault

Arlettaz

et al. 2005

Medicine &Amp; Science in Sports &Amp; Exercise

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This study shows a negative effect of clenbuterol and salbutamol on the mechanical properties and microarchitecture of trabecular bone. In the clenbuterol group it was notable that the bone loss contrasts with the anabolic effect on muscle mass. Clearly an increase of muscle mass with enhanced bone fragility augments the risk of fractures for humans or animals treated with beta2 agonists as part of a doping regimen.

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Effect of calcium stress on the skeleton mass of intact and ovariectomized rats

Cited by 21 publications

References 24 publications

Effects of Bioactive Peptide, Valyl-Prolyl-Proline (VPP), and <i>Lactobacillus helveticus</i> Fermented Milk Containing VPP on Bone Loss in Ovariectomized Rats

Effects of Bioactive Peptide, Valyl-Prolyl-Proline (VPP), and <i>Lactobacillus helveticus</i> Fermented Milk Containing VPP on Bone Loss in Ovariectomized Rats

Ovariectomy worsens secondary hyperparathyroidism in mature rats during low-Ca diet

Alteration of Trabecular Bone under Chronic β2 Agonists Treatment

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