Short Cyclic Regimen with Parathyroid Hormone ( PTH ) Results in Prolonged Anabolic Effect Relative to Continuous Treatment Followed by Discontinuation in Ovariectomized Rats

IntroductionFracture healing is a complex physiological process. Impaired healing will increase the need for care and cause serious complications. Thus, identifying strategies to accelerate the rate of healing, preventing delayed unions and non-unions, is essential. Parathyroid hormone (PTH) is a key systemic regulator of calcium and phosphate metabolism. It has been determined that intermittent administration of PTH and its analogue can exert anabolic effect on bone, increase bone mass and reduce bone loss, leading to an increase in bone formation. Owing to their anabolic effect, there is an increasing interest in its potential in promoting the process of fracture healing. However, in clinical studies, the results are in conflict. This objective of this study is to determine the role of PTH analogues for fracture healing in adults.Methods and analysisMEDLINE, EMBASE and Cochrane databases will be searched to identify all randomised controlled trials (RCTs) and quasi-RCTs that compare the different effects between PTH analogues and any other treatments in adults with any type of fracture. The primary outcome is the functional recovery. And the secondary outcomes are fracture union and adverse events. The meta-analysis will be performed using a random effects model. Heterogeneity will be assessed by the P values and I² statistic. And subgroup analyses and sensitivity analyses will be used to explore the heterogeneity. Risk of bias will be assessed using the Cochrane tool and the quality of evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation approach.Ethics and disseminationEthical approval is not required because this proposed systematic review and meta-analysis is based on published data, without including confidential personal data or data on interventions on patients. The findings of this study will be published in a peer-reviewed journaland presented at a relevant conference.PROSPERO registration numberCRD42017062093.

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Estrogens and progestogens conserve bone in rats deficient in calcitonin and parathyroid hormone

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1989.257.6.e903 ◽

1989 ◽

Vol 257 (6) ◽

pp. E903-E908

Author(s):

A. Goulding ◽

E. Gold

Keyword(s):

Parathyroid Hormone ◽

Bone Resorption ◽

Ovariectomized Rats ◽

Lower Plasma ◽

Urinary Hydroxyproline ◽

Dihydroxyvitamin D ◽

1,25 Dihydroxyvitamin D ◽

Thyroxine Replacement ◽

Total Body ◽

D Values

To examine the abilities of estrogens and progestogens to slow bone resorption and conserve bone in ovariectomized rats deficient in calcitonin (CT) or parathyroid hormone (PTH), nine groups of animals with 45Ca-labeled bones were studied for 12 wk. Rats were thyroidectomized (TX), parathyroidectomized (PTX), or given sham neck operations (Sham) and treated orally with either estrogen, 300 micrograms 17 beta-estradiol.kg body wt-1.wk-1; progestogen, 500 micrograms norethisterone acetate.kg body wt-1.wk-1; or placebo (Plac). The TX rats had parathyroid autografts and thyroxine replacement. In all surgical groups, estradiol (E2) and norethindrone (Nor) slowed urinary 45Ca excretion and conserved bone (P less than 0.001). However E2 lowered urinary hydroxyproline more than Nor. Total body Ca values (mg +/- SD) were Sham + Plac, 3,079 +/- 201; Sham + E2, 3,886 +/- 335; Sham + Nor, 3,567 +/- 459; TX + Plac, 3,123 +/- 159; TX + E2, 3,869 +/- 235; TX + Nor, 3,540 +/- 422; PTX + Sham, 3,067 +/- 249; PTX + E2, 3,775 +/- 414; PTX + Nor, 3,635 +/- 467. Importantly, E2 and Nor conserved bone as effectively in TX and PTX groups as in Sham rats, although the PTX rats had slower bone resorption and lower plasma 1,25-dihydroxyvitamin D values (P less than 0.001) than groups with intact parathyroids. We conclude that the effects of estrogens and progestogens to slow bone resorption and conserve bone are independent of CT and PTH. These findings appear relevant to the pathogenesis and treatment of postmenopausal osteoporosis.

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