scholarly journals Increasing dietary nitrate has no effect on cancellous bone loss or fecal microbiome in ovariectomized rats

2017 ◽  
Vol 61 (5) ◽  
pp. 1600372 ◽  
Author(s):  
Melissa N. Conley ◽  
Cooper Roberts ◽  
Thomas J. Sharpton ◽  
Urszula T. Iwaniec ◽  
Norman G. Hord
Keyword(s):  
Bone Loss ◽  
Cancellous Bone ◽  
Ovariectomized Rats ◽  
Dietary Nitrate ◽  
Fecal Microbiome

Effects of droloxifene on prevention of cancellous bone loss and bone turnover in the axial skeleton of aged, ovariectomized rats

Bone ◽  
1995 ◽  
Vol 17 (5) ◽  
pp. 491-496 ◽  
Author(s):  
H.Z. Ke ◽  
H.K. Chen ◽  
H. Qi ◽  
C.M. Pirie ◽  
H.A. Simmons ◽  
...  
Keyword(s):  
Bone Loss ◽  
Bone Turnover ◽  
Cancellous Bone ◽  
Axial Skeleton ◽  
Ovariectomized Rats

5 alpha-Dihydrotestosterone partially restores cancellous bone volume in osteopenic ovariectomized rats

1994 ◽  
Vol 267 (6) ◽  
pp. E853-E859 ◽  
Author(s):  
J. H. Tobias ◽  
A. Gallagher ◽  
T. J. Chambers
Keyword(s):  
Bone Resorption ◽  
Bone Loss ◽  
Bone Formation ◽  
Cancellous Bone ◽  
Bone Growth ◽  
Bone Volume ◽  
Ovariectomized Rats ◽  
Trabecular Thickness ◽  
Longitudinal Bone Growth ◽  
Periosteal Bone Formation

Although androgens are thought to be important for skeletal maintenance in females and males, little is known about the mechanisms involved. To investigate this question further, we examined the effects of administering 0.01, 0.1, or 1.0 mg/kg 5 alpha-dihydrotestosterone (DHT) for 60 days on the skeleton of ovariectomized rats. Treatment was delayed until 90 days after ovariectomy to enable bone loss to stabilize. We found that ovariectomy markedly reduced cancellous bone volume of the proximal tibial metaphysis due to a combination of loss and thinning of trabeculae. Cancellous bone volume was partially restored by all doses of DHT, with trabecular thickness, but not number, returning to that of sham-operated animals. DHT also stimulated longitudinal bone growth and endosteal and periosteal bone formation and suppressed histomorphometric indexes of cancellous bone resorption. This suggests that DHT influences skeletal metabolism in osteopenic ovariectomized rats both by stimulating bone formation and suppressing resorption, although it is unclear which, if any, of these actions predominate at cancellous sites.

scholarly journals Clomiphene Prevents Cancellous Bone Loss from Tibia of Ovariectomized Rats

Endocrinology ◽  
1997 ◽  
Vol 138 (5) ◽  
pp. 1794-1800 ◽  
Author(s):  
M. A. Jimenez ◽  
D. E. Magee ◽  
H. U. Bryant ◽  
R. T. Turner
Keyword(s):  
Bone Loss ◽  
Cancellous Bone ◽  
Ovariectomized Rats

Discriminant capacity of quantitative ultrasound versus dual X-Ray absorptiometry to determine cancellous bone loss in ovariectomized rats

Bone ◽  
2000 ◽  
Vol 26 (3) ◽  
pp. 297-303 ◽  
Author(s):  
G Giavaresi ◽  
F De Terlizzi ◽  
S Gnudi ◽  
R Cadossi ◽  
N.Nicoli Aldini ◽  
...  
Keyword(s):  
Bone Loss ◽  
Cancellous Bone ◽  
Quantitative Ultrasound ◽  
Ovariectomized Rats ◽  
X Ray

Distinct effects of ovarian transplantation and exogenous 17 β-oestradiol on cancellous bone of osteopenic ovariectomized rats

1995 ◽  
Vol 133 (4) ◽  
pp. 483-488 ◽  
Author(s):  
Andrea C Gallagher ◽  
Timothy J Chambers ◽  
Jonathan H Tobias
Keyword(s):  
Bone Loss ◽  
Bone Metabolism ◽  
Cancellous Bone ◽  
Ovarian Function ◽  
Bone Volume ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Serum Progesterone ◽  
Ovarian Transplantation ◽  
Ovx Rats

Gallagher AC, Chambers TJ, Tobias JH. Distinct effects of ovarian transplantation and exogenous 17 β-oestradiol on cancellous bone of osteopenic ovariectomized rats. Eur J Endocrinol 1995;133:483–8. ISSN 0804–4643 Although 17 β-oestradiol (E2) is known to prevent bone loss, prolonged administration of E2 is unable to reverse this in female rats rendered osteopenic by ovariectomy. To determine whether this reflects a failure to replace other components of ovarian function involved in bone metabolism, we compared the effects of administering E2 to osteopenic ovariectomized (ovx) rats with those of ovarian transplantation. Ovariectomy was performed in female rats. After 13 weeks, by which time marked bone loss had occurred, one group of ovx animals received ovaries from donor rats, and, after a delay of 2 weeks to allow oestrus cycles to return, a further group received E2 5 μg · kg−1 · day−1 for 9 weeks. The dose of E2 was chosen as that which in preliminary studies restored mean serum E2 levels to that of intact female rats. The study was terminated 24 weeks after ovariectomy. Both E2 and ovarian transplantation largely restored indices of oestrogenic exposure in ovx rats to those of sham-ovx animals. Animals receiving ovarian transplants also showed a small increase in serum progesterone and full restoration of serum testosterone. However, while ovarian transplantation also returned indices of cancellous bone metabolism to those of sham-ovx animals, there was little increase in bone volume. Interestingly, exogenous E2 caused a greater increase in cancellous bone volume than ovarian transplantation but also caused more marked suppression of bone formation, as assessed at the end of the study. In conclusion, exogenous E2 and ovarian transplantation exerted distinct effects on skeletal metabolism in osteopenic ovx rats, although the basis for this difference is currently unclear. JH Tobias, Department of Histopathology, St George's Hospital Medical School, London SW17 ORE, UK

The effects of ovarian transplantation on bone loss in ovariectomized rats

1994 ◽  
Vol 142 (1) ◽  
pp. 187-192 ◽  
Author(s):  
J H Tobias ◽  
T J Chambers ◽  
A Gallagher
Keyword(s):  
Bone Loss ◽  
Cancellous Bone ◽  
Ovarian Function ◽  
Hormone Replacement ◽  
Bone Volume ◽  
Ovariectomized Rats ◽  
Vaginal Smears ◽  
Trabecular Thickness ◽  
Ovarian Transplantation ◽  
Trabecular Number

Abstract Although hormone replacement therapy can prevent postmenopausal bone loss, it does not restore bone mass to normal in patients with established osteoporosis. This might reflect a failure to reproduce certain aspects of gonadal function. One method of investigating this possibility would be to examine the effect of ovarian transplantation on the skeleton of osteopaenic ovariectomized rats. However, ovarian transplantation may not fully restore ovarian function to normal, and it is not known whether transplanted ovaries reproduce the action of native ovaries on the skeleton. Therefore, we investigated whether renal capsular or subcutaneous ovarian transplants prevent the effects of ovariectomy on histomorphometric indices of rat tibiae over 44 days. Daily vaginal smears showed that oestrous cycles returned in all but two of 25 animals receiving ovarian transplants. We found that ovarian transplantation prevented the reduction in cancellous bone volume following ovariectomy. While trabecular number was reduced in ovariectomized animals receiving renal capsular ovarian transplants compared to intact animals, trabecular thickness was increased in both transplant groups. Ovarian transplantation also prevented the increase in cancellous and cortical bone formation, cancellous bone resorption and longitudinal growth rate caused by ovariectomy. We conclude that restoration of ovarian function by ovarian transplantation largely prevents the effects of ovariectomy on histomorphometric indices of rat tibiae, suggesting that transplanted ovaries can substitute for the action of native ovaries on the skeleton. Journal of Endocrinology (1994) 142, 187–192

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