Age Dependence of Estrogen Responsiveness

Judd, J.; Kremer, M.; Oursler, Merry Jo

doi:10.1007/bf03354647

Cited by 2 publications

(2 citation statements)

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“…Perhaps older CBC cultures responded differently than younger cultures because the osteogenic potential of older cultures was less than younger cultures (i.e., fewer osteoblast and progenitor cells in older cultures) (Stein et al 1989;Heersche et al 1992). Similarly, co-culture response varied depending on the source of the osteoclastic cells, which may be a reflection of the particular cell's level of various surface receptors as shown by others (Judd et al 1995).…”

Section: Discussionmentioning

confidence: 86%

“…Previous studies by Judd et al (1995) had demonstrated differences in chicken osteoclasts' responsiveness to exogenous estrogen was dependent on the age of chicken from which the cells were derived. To explore this issue further, we examined co-culture effects using osteoclastic cells from chickens at several stages of maturity, including embryonic chickens and chick hatchlings (maintained on calcium-deficient diets for 28 days).…”

Section: Harvest Of Osteoclastic Cellsmentioning

confidence: 98%

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Osteogenic and osteoclastic cell interaction: development of a co-culture system

Loomer

Ellen

Tenenbaum

1998

Cell and Tissue Research

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The processes involved in the regulation of bone cell metabolism are complex, including those implicated in bone cell coupling. This study was undertaken to develop a model that would permit real-time interaction between osteoclastic cells and osteoblasts in vitro. Osteogenic bone marrow stromal cells were isolated from 18-day-old embryonic chickens, while osteoclastic cells were isolated from laying White Leghorn hens on calcium-deficient diets. Osteoclastic cells (5x10(5)) were seeded onto mineral thin films and suspended above osteogenic cells (1x10(4)) already plated on the bottoms of tissue culture plate wells. The data showed that after 4 days of incubation there was up to a fivefold (P<0.05) reduction in all measured parameters of osteogenesis (mineralization, alkaline phosphatase activity and type I collagen production) in osteogenic cultures grown in the presence of osteoclastic cells. Similarly, osteoclastic cell-induced mineral resorption was reduced up to threefold (P<0.05). Co-culture effects on cellular responses could be manipulated by known antiresorptive agents (e.g., pamidronate) altering either the source or the age of osteoclastic cells. The results indicate that the co-culture model may be useful in the study of bone cell interactions.

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Section: Discussionmentioning

confidence: 86%

Section: Harvest Of Osteoclastic Cellsmentioning

confidence: 98%

Osteogenic and osteoclastic cell interaction: development of a co-culture system

Loomer

Ellen

Tenenbaum

1998

Cell and Tissue Research

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Positive interaction between 17β-estradiol and parathyroid hormone in normal human osteoblasts cultured long term in the presence of dexamethasone

et al. 1996

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We previously developed two models of human osteoblasts with distinct differentiation stages using cells derived from iliac crest trabecular bone explants cultured long term in the presence (HOB + DEX) and absence (HOB - DEX) of 10 nM dexamethasone (DEX) (Wong et al., J Bone Miner Res 1990;5:803). Using these models from 36 subjects aged 41-80 years, we examined the effects of 17 beta-estradiol (E2) on cell proliferation, osteocalcin (OC) production, alkaline phosphatase (ALP) and basal and parathyroid hormone (PTH)-stimulated adenylate cyclase activities, as well as the steady-state mRNA levels of ALP, collagen type I(COLL), OC, and receptors for E2 (ER) and PTH (PTHr). E2 alone had no effect on [3H]thymidine uptake in (HOB - DEX) cells but appeared to stimulate the uptake in (HOB + DEX) cells in a dose-dependent manner, with maximum effect at 10(-10)M (p < 0.05). However, in the presence of 10(-6)M PTH, E2 inhibited the uptake in (HOB - DEX) cells (ANOVA, KW = 18.95, p < 0.005) but stimulated the uptake in (HOB + DEX) cells (KW = 13.52, p < 0.025). E2 decreased the amount of osteocalcin in culture media from both (HOB - DEX) and (HOB + DEX) cells (p < 0.05). PTH alone or E2, alone or in combination with 10(-9)M PTH, had no effect on ALP activity in (HOB - DEX) cells. In contrast, in (HOB + DEX) cells, E2 + PTH but not E2 alone, had biphasic effects on ALP activity, with maximum stimulation observed at 10(-11) and 10(-10)M E2, and a return to basal levels at 10(-9)M E2. E2 decreased basal adenylate cyclase activities in a dose-dependent manner in (HOB + DEX) but not (HOB - DEX) cells (KW = 13.48, p < 0.05). In (HOB + DEX) cells, E2 had biphasic effects on PTH-stimulated adenylate cyclase activity, with significant stimulation observed at 10(-10)M (p < 0.05). While E2 had no significant effect on osteoblastic marker mRNA levels in (HOB - DEX) cells, it decreased osteocalcin and stimulated PTHr mRNA levels in (HOB + DEX) cells. Thus, in our human osteoblastic cell models, estrogen regulated metabolic function largely in the more differentiated cells, by modifying the effects of PTH.

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Age Dependence of Estrogen Responsiveness

Cited by 2 publications

References 3 publications

Osteogenic and osteoclastic cell interaction: development of a co-culture system

Osteogenic and osteoclastic cell interaction: development of a co-culture system

Positive interaction between 17β-estradiol and parathyroid hormone in normal human osteoblasts cultured long term in the presence of dexamethasone

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