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  • 1
    Electronic Resource
    Electronic Resource
    Differences in Bone Turnover and Skeletal Response to Thyroid Hormone Treatment Between Estrogen-Depleted and Repleted Rats (2000)
    Springer
    Calcified tissue international 67 (2000), S. 173-177 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Bone mass — Thyroxine — Ovariectomy — Bone turnover.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. This study was undertaken to compare the effect of supraphysiological doses of thyroxine (T4) on bone metabolism in SHAM and OVX young adult rats. Female Sprague Dawley rats (220 ± 2 g, approx. 5 months of age) were divided into four groups of eight animals each. The animals were intraperitoneally injected 6 days per week with vehicle (Vh): 0.001 N NaOH/0.9% NaCl (SHAM+Vh and OVX+Vh) or 250 μg of thyroxine/kg/day (SHAM+T4 and OVX+T4) during a 5-week period. Serum T4 and osteocalcin (BGP), urinary pyridinolines (Pyr), and creatinine (creat) were determined. At the beginning and at end of the experiment, skeletal bone mineral content (BMC), bone mineral density (BMD), and area (A) of the total skeleton, femur, spine, and whole tibia, as well as proximal, middle, and distal areas of the tibia were assessed by dual X-ray absorptiometry (DXA) in an ultra-high-resolution mode. T4 treatment of the SHAM rats did not induce significant changes in BGP level or Pyr/creat excretion compared with the SHAM+Vh control group. However, these two biochemical bone markers significantly increased due to T4 treatment in OVX rats compared with both OVX+Vh and SHAM+T4 groups (P 〈 0.05 and P 〈 0.001, respectively). The OVX+T4 group had a significantly lower ΔBMD than SHAM+T4 rats in all studied regions (P 〈 0.05) except for the middle tibia region. OVX+T4 groups presented a significantly lower ΔBMC and ΔA compared with SHAM+T4 animals (P 〈 0.001). OVX+T4 rats significantly impaired the ΔBMD in the femur (P 〈 0.01), spine (P 〈 0.05), whole (P 〈 0.05) and middle (P 〈 0.05) tibia whereas T4 treatment of SHAM rats only affected, significantly, the whole (P 〈 0.05) and the proximal tibia region (P 〈 0.01). T4 treatment affects bone growth in young adult rats. The effect is significantly greater in the estrogen-depleted than in the estrogen-repleted state. The bone site most adversely affected by T4 treatment depends on the estrogen status. The proximal tibia (principally trabecular bone) was the most affected area in estrogen-repleted rats. Conversely, in OVX rats, the middle tibia (principally cortical bone) presented the greatest decrease in bone density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00223001106
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  • 2
    Electronic Resource
    Electronic Resource
    Hyperthyroidism Influences Ultrasound Bone Measurement on the Os Calcis (1998)
    Springer
    Osteoporosis international 8 (1998), S. 455-459 
    Details
    ISSN: 1433-2965
    Keywords: Key words:BMD – Bone loss – Hyperthyroidism – Ultrasound parameters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: The objective of our study was to compare bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) and quantitative ultrasound (QUS) parameters in women with hyperthyroidism and controls. In this cross-sectional study, QUS parameters and BMD values observed in untreated hyperthyroid patients were compared with data obtained from age-matched controls. Twenty-four women with Graves' disease were studied. Eight patients were postmenopausal. All patients had evidence of thyrotoxicosis as indicated by a raised total serum thyroxine and a suppressed serum thyroid stimulating hormone. BMD of the hip, lumbar spine and whole body, and body composition, were measured by DXA. Ultrasound evaluation on the os calcis was performed with an Achilles device. All measurements were performed before antithyroid therapy. The QUS parameters of BUA, SOS and Stiffness were significantly lower in hyperthyroid patients than in controls. Similar results were observed for the BMD of lumbar spine, femoral neck and total skeleton. Lean tissue and fat mass were also significantly decreased in hyperthyroid patients. In conclusion, these findings suggest that hyperthyroidism affects cortical and trabecular bone equally, as well as bone quality. QUS measurements may be helpful for assessing, using a simple and non-irradiating method, the bone effects of thyrotoxicosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001980050091
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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