Long-Term Sensitivity of Uterus and Hypothalamus/Pituitary Axis to 17β-Estradiol Is Higher Than That of Bone in Rats

Erben, Reinhold G.; Brunner, Katrin S.; Breig, Bianca

doi:10.1359/jbmr.040815

Cited by 13 publications

(11 citation statements)

References 28 publications

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“…Furthermore, osteocalcin values were significantly reduced by administration of E 2 in both experimental models. Similar findings have recently been reported that ovx resulted in elevated levels of ALP and osteocalcin, and E 2 supplementation reversed these effects [15,34]. RLX significantly increased osteocalcin levels in the presence of endogenous estrogen, but had decreasing effects in the ovx model.…”

Section: Discussionsupporting

confidence: 88%

Effects of raloxifene and estradiol on bone turnover parameters in intact and ovariectomized rats

et al. 2010

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This study was designed to investigate effects of raloxifene (RLX) and estradiol on bone formation and resorption in intact and ovariectomized (ovx) rat models. In the intact model, a total of 24 adult female rats were divided into three groups: Controls subcutaneously received saline alone. RLX (2 mg/kg) and estradiol (30 microg/kg) were injected to two groups of animals for a period of 6 weeks at two daily intervals. In the second model, rats (n = 24) were ovx and allowed to recover for a period of at least 3 weeks. Control group received vehicle alone. Remaining rats were divided into two groups and injected with RLX (2 mg/kg) and estradiol (30 microg/kg) for 6 weeks. Urine samples were collected from all animals 24 h after the last drug administration. Urinary deoxypyridinoline (DPD) was measured by ELISA. Serum parathyroid hormone (PTH), calcitonin, and osteocalcin levels were measured by immunoradiometric method. Serum concentrations of alkaline phosphatase (ALP), Ca, and inorganic phosphate were determined by enzymatic-colorimetric method. Lumbar vertebrae (L2) of all animals were dissected out and processed for histopathological evaluation. Removal of ovaries significantly elevated urinary DPD levels (p < 0.01) compared with intact controls. Treatment of both intact and ovx rats with estradiol resulted in significant decreases (p < 0.01) in DPD values. RLX administration had no significant effect in the intact rats, but it remarkably reduced bone turnover in the ovx animals (p < 0.001). Both estradiol and RLX produced conflicting effects on serum ALP, osteocalcin, and PTH levels in both animal models. These findings suggest that RLX exerts its protective effects by reducing bone resorption, similar to that of estradiol, in ovx rats.

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Section: Discussionsupporting

confidence: 88%

Effects of raloxifene and estradiol on bone turnover parameters in intact and ovariectomized rats

et al. 2010

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“…# p \ 0.05 for versus SED group, *p \ 0.05 for versus EX group the increase in body weight in the EX-FR group was inhibited, and the uterus weight in the EX-FR group was significantly lower than that in the EX and SED-FR groups. It was reported that low uterus weight can be caused by estradiol deficiency [26]. Thus, in the present study, it may be that rats in the EX-FR group exhibited abnormal estradiol secretion due to low energy availability.…”

Section: Discussionmentioning

confidence: 49%

The Interaction of Voluntary Running Exercise and Food Restriction Induces Low Bone Strength and Low Bone Mineral Density in Young Female Rats

et al. 2015

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There is a concern that the combination of exercise with food intake reduction has a risk of reducing bone strength and bone mass in young female athletes. We examined the influence of the interaction of voluntary running exercise and food restriction on bone in young female rats. Seven-week-old female Sprague-Dawley rats were divided into four groups: the sedentary and ad libitum feeding group (SED), voluntary running exercise and ad libitum feeding group (EX), sedentary and 30 % food restriction group (SED-FR), and voluntary running exercise and 30 % food restriction group (EX-FR). The experiment lasted 12 weeks. Statistical analysis was carried out by two-way analysis of variance with exercise and restriction as the between-subjects factors. As a result, there were significant interactions of running and restriction on energy availability, breaking force, breaking energy, and bone mineral density (BMD). Breaking force and energy in the EX group were significantly higher than in the SED group; breaking force and energy were significantly lower in the EX-FR group than in the EX group, and breaking force in the EX-FR group was significantly lower than that in the SED-FR group. BMD in the EX-FR group was significantly lower than in the EX and SED-FR groups. These results suggest that food restriction induced low bone strength in young female rats engaging in voluntary running exercise. Also, through the interaction of exercise and food restriction, voluntary running exercise combined food restriction, unlike ad libitum feeding conditions, induced low bone strength, and low BMD in young female rats.

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“…2B). Compared to other tissues, the uterus contains a relatively high number of ERs and, thus, a bioassay of the uterotrophic effects of E2 is considered a highly sensitive test and a positive control for demonstrating E2 action in vivo (Adams et al, 2002; Erben et al, 2004). …”

Section: Resultsmentioning

confidence: 99%

Estradiol Reverses a Calcium-Related Biomarker of Brain Aging in Female Rats

Brewer¹,

Dowling²,

Curran-Rauhut³

et al. 2009

J. Neurosci.

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An increase in L-type voltage-gated calcium channel (LTCC) current is a prominent biomarker of brain aging and is believed to contribute to cognitive decline and vulnerability to neuropathologies. Studies examining age-related changes in LTCCs have focused primarily on males, although estrogen (17␤-estradiol, E2) affects calcium-dependent activities associated with cognition. Therefore, to better understand brain aging in females, the effects of chronic E2 replacement on LTCC current activity in hippocampal neurons of young and aged ovariectomized rats were determined. The zipper slice preparation was used to expose cornu ammonis 1 (CA1) pyramidal neurons for recording LTCC currents using the cell-attached patch-clamp technique. We found that an age-related increase in LTCC current in neurons from control animals was prevented by E2 treatment. In addition, in situ hybridization revealed that within stratum pyramidale of the CA1 area, mRNA expression of the Ca v 1.2 LTCC subunit, but not the Ca v 1.3 subunit, was decreased in aged E2-treated rats. Thus, the reported benefits of E2 on cognition and neuronal health may be attributed, at least in part, to its age-related decrease in LTCC current.

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Long-Term Sensitivity of Uterus and Hypothalamus/Pituitary Axis to 17β-Estradiol Is Higher Than That of Bone in Rats

Cited by 13 publications

References 28 publications

Effects of raloxifene and estradiol on bone turnover parameters in intact and ovariectomized rats

Effects of raloxifene and estradiol on bone turnover parameters in intact and ovariectomized rats

The Interaction of Voluntary Running Exercise and Food Restriction Induces Low Bone Strength and Low Bone Mineral Density in Young Female Rats

Estradiol Reverses a Calcium-Related Biomarker of Brain Aging in Female Rats

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