Estrogen dose required to maintain parathyroid hormone mediated bone gain in osteopenic ovariectomized rats is probably higher than in preventive treatment with estrogen

Cheng, Pei‐Tak; Aye, Lydia; Vieth, Reinhold; Müller, Klaus

doi:10.1016/8756-3282(95)00310-a

Cited by 7 publications

(2 citation statements)

References 22 publications

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“…The first explanation would speak for two set points in the rat skeleton, estrogen‐replete and estrogen‐deficient. The latter explanation would suggest that a level of estrogen beyond normal physiological fluctuations is important in maintaining extra bone when there is no longer ongoing anabolic activity, an assertion also presented by others 22 , 23…”

Section: Discussionmentioning

confidence: 72%

Accretion of Bone Mass and Strength with Parathyroid Hormone Prior to the Onset of Estrogen Deficiency Can Provide Temporary Beneficial Effects in Skeletally Mature Rats

Shen

Birchman

Liang

et al. 1998

Journal of Bone and Mineral Research

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Intermittent administration of parathyroid hormone (PTH) has been shown to be an anabolic agent for animal and human skeletons. In previous studies, PTH has been used concurrent with, or subsequent to, the onset of bone loss. However, it is entirely possible that PTH may be used as an anabolic agent in a situation where there is stable skeletal remodeling. Increasing bone mass at this time might confer long-lasting beneficial effects when bone loss begins, for example, subsequent to the loss of ovarian function. To test this hypothesis, we evaluated the effects of administering rat PTH(1-34) (80 g/kg/day, subucutaneously [sc]) to 6-month-old rats for a 2-week period prior to ovariectomy, and followed the natural occurrence of bone loss over a 14-week period. To determine the effects of estrogen intervention on bone gained by PTH treatment, one group was repleted with 17␤-estradiol (10 g/kg/day via sc implant). Serial measurements of bone mass in vivo at the distal femur were obtained at 2-week intervals using dual-energy X-ray absorptiometry, while histologic and mechanical strength data were obtained from excised proximal tibiae and distal femurs after sacrifice. Two weeks of PTH treatment resulted in an increase of bone mineral density (BMD), mechanical strength, and cancellous bone volume (CnBV/TV). Four weeks after PTH withdrawal, significant residual beneficial effects on BMD and strength, irrespective of ovarian status, were observed. However, 14 weeks after PTH withdrawal, although there were still residual effects on CnBV/TV in ovariectomized animals pretreated with PTH, the PTH effects on BMD and mechanical strength had been lost. Estradiol repletion during the rapid bone loss phase following ovariectomy prevented the reduction in BMD associated with either ovariectomy or PTH withdrawal. Our results suggest that: treatment of rats with PTH prior to ovariectomy produces an increase in BMD and strength, these beneficial effects extend for a period of at least three times the treatment duration, the BMD that is lost when PTH is discontinued equates to the amount accrued during the PTH treatment, estrogen replacement can be used to maintain the bone gained as a result of PTH treatment. (J Bone Miner Res 1998;13:883-890)

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Section: Discussionmentioning

confidence: 72%

Accretion of Bone Mass and Strength with Parathyroid Hormone Prior to the Onset of Estrogen Deficiency Can Provide Temporary Beneficial Effects in Skeletally Mature Rats

Shen

Birchman

Liang

et al. 1998

Journal of Bone and Mineral Research

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“…Untreated (vehicle) group after 12 weeks was either sham operated or ovariectomized and was further divided into three groups as follows: ovary intact sham group given vehicle (sham + veh; n = 15), OVx rats given vehicle (OVx + veh; n = 15), and OVx rats given 10.0 μ g/kg/d E2 by oral gavage (OVx + E2; n = 15). E2 dose was based on previous reports [18]. The animals were housed for another 12 weeks after which they were killed.…”

Section: Methodsmentioning

confidence: 99%

Greater Skeletal Gains in Ovary Intact Rats at Maturity Are Achieved by Supplementing a Standardized Extract ofButea monospermaStem Bark that Confers Better Bone Conserving Effect following Ovariectomy and Concurrent Treatment Withdrawal

Srivastava

Khan

Tyagi

et al. 2013

Evidence-Based Complementary and Alternative Medicine

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With a longitudinally designed study, we tested whether an acetone soluble fraction (ASF) from the stem bark of Butea monosperma resulted in maximizing bone gain in rats during growth and maturation and thus protected against osteopenia following ovariectomy (OVx) with concomitant treatment withdrawal. Female rats at weaning were given ASF (100 mg/kg/d) or vehicle for 12 weeks, and baseline skeletal parameters (micro-CT) and total plasma antioxidant status (TAS) were measured. At this stage, one group was OVx and the other group was sham operated. Vehicle group (untreated) after OVx was given E2 or continued with vehicle (OVx control). ASF group after OVx was given vehicle (ASF withdrawn, ASFW). After another 12 weeks, all groups were killed and various skeletal parameters were determined. ASF resulted in substantially better skeletal parameters and higher plasma TAS over control at maturity. Rats treated with ASF before OVx had reduced rates of bone loss compared to OVx control. Twelve weeks after OVx, the ASFW group exhibited better trabecular microarchitectural preservation, bone turnover profiles, increased cortical deposition, and biomechanical strength over the OVx control, and the effects were comparable to OVx + E2 group. ASF supplementation during skeletal growth could maximize bone accrual and could confer increased resistance to post-OVx osteopenia despite treatment withdrawal.

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Maintenance therapy for added bone mass or how to keep the profit after withdrawal of therapy of osteopenia

Jee

Chow

1995

Bone

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Estrogen dose required to maintain parathyroid hormone mediated bone gain in osteopenic ovariectomized rats is probably higher than in preventive treatment with estrogen

Cited by 7 publications

References 22 publications

Accretion of Bone Mass and Strength with Parathyroid Hormone Prior to the Onset of Estrogen Deficiency Can Provide Temporary Beneficial Effects in Skeletally Mature Rats

Accretion of Bone Mass and Strength with Parathyroid Hormone Prior to the Onset of Estrogen Deficiency Can Provide Temporary Beneficial Effects in Skeletally Mature Rats

Greater Skeletal Gains in Ovary Intact Rats at Maturity Are Achieved by Supplementing a Standardized Extract ofButea monospermaStem Bark that Confers Better Bone Conserving Effect following Ovariectomy and Concurrent Treatment Withdrawal

Maintenance therapy for added bone mass or how to keep the profit after withdrawal of therapy of osteopenia

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