Growth hormone and parathyroid hormone stimulate IGFBP-3 in rat osteoblasts

Schmid, C; Schläpfer, I.; Peter, M.; Böni-Schnetzler, Marianne; Schwander, J; Zapf, J.; Froesch, E. R.

doi:10.1152/ajpendo.1994.267.2.e226

Cited by 33 publications

(31 citation statements)

References 34 publications

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“…The air-dried filters were washed in Cultured rat osteoblasts produce mainly IGF I [4] and reTris-buffered saline (TBS; 0.15 M NaC1 and 0.01 M Tris, pH 7.4) lease IGFBP-2 and IGFBP-3 into the medium [5,6]. IGFBP-5 containing 0.1% Tween 20 and then incubated with 125I-labeled IGF II (4X 106 cpm per plastic bag) for 6 h at room temperature.…”

Section: Processing Of Culture Media Blot Analysis For Igfbps and Ramentioning

confidence: 99%

“…cassettes equipped with intensifying screens as described [6]. IGF I, prostaglandin E2, and parathyroid hormone increase For irrmaunoblot analysis 30-gl aliquots were loaded per lane.…”

Section: Processing Of Culture Media Blot Analysis For Igfbps and Ramentioning

confidence: 99%

“…The IGFBP-5 mRNA in cultured perinatal rat calvaria-derived air-dried filters were washed in TBS pH 7.6 containing 0.1% Tween 20. The first antibody (anti-IGFBP-5) was used at a dilution of cells [6,10]. In contrast to IGFBP-3, IGFBP-5 is preferentially 1:1000, the second (anti-guinea pig, horse-radish peroxidase-conjubound to extracellular matrix in human fibroblast cultures gated, from Anawa, Wangen, Switzerland) at a dilution of 1:500.…”

Section: Processing Of Culture Media Blot Analysis For Igfbps and Ramentioning

confidence: 99%

“…IGF I was extracted by Sep-Pak C18 cartridges and determined it with the effect of PTH on IGFBP-5 mRNA and on IGFBPusing rabbit antiserum (1:20000) against human IGF I and pure rat 5 in the conditioned culture medium and the cell layer of rat IGF I (gift from Dr. Kobayashi, Fujisawa, Japan) as a standard [6]. osteoblast cultures because calcium-regulating hormones may use IGF to mediate part of their effects on bone turnover.…”

Section: Processing Of Culture Media Blot Analysis For Igfbps and Ramentioning

confidence: 99%

“…Cell culture (PTH). These two calcium-regulating hormones stimulated the Osteoblast-like cells were prepared from calvaria of newborn rats expression of IGFBP-5 mRNA in cultured rat osteoblasts at low by sequential digestion with collagenase (CLS II, Worthington) [6]. concentrations (10 pM) and in a dose-and time-dependent Primary cell cultures were trypsinized and 106 cells were plated per 10 manner.…”

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1α,25‐Dihydroxyvitamin D₃ increases IGF binding protein‐5 expression in cultured osteoblasts

et al. 1996

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(BSA) (Sigma) was treated with charcoal to remove fatty acids and Abstract Rat osteoblasts produce insulin-like growth factors steroid hormones. Guinea pig anti-serum raised against human (IGFs) and IGF binding proteins (IGFBPs). Expression of IGFBP-5 was a generous gift from D.R. Clemmons, University of IGFBP-5, an IGFBP which stimulates DNA synthesis of North Carolina (Chapel Hill, NC) [13]. osteoblasts, was studied in vitro under the influence of hz,25-dihydroxyvitamin D3 (1,25(OH)2D3) and parathyroid hormone 2.2. Cell culture (PTH). These two calcium-regulating hormones stimulated the Osteoblast-like cells were prepared from calvaria of newborn rats expression of IGFBP-5 mRNA in cultured rat osteoblasts at low by sequential digestion with collagenase (CLS II, Worthington) [6]. concentrations (10 pM) and in a dose-and time-dependent Primary cell cultures were trypsinized and 106 cells were plated per 10 manner. Intact IGFBP-5 was not detected in the culture medium, cm diameter (55 cm 2 surface) dishes in phenol red-free c~-modified but was found attached to the cell layer.

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Section: Processing Of Culture Media Blot Analysis For Igfbps and Ramentioning

confidence: 99%

“…cassettes equipped with intensifying screens as described [6]. IGF I, prostaglandin E2, and parathyroid hormone increase For irrmaunoblot analysis 30-gl aliquots were loaded per lane.…”

Section: Processing Of Culture Media Blot Analysis For Igfbps and Ramentioning

confidence: 99%

Section: Processing Of Culture Media Blot Analysis For Igfbps and Ramentioning

confidence: 99%

Section: Processing Of Culture Media Blot Analysis For Igfbps and Ramentioning

confidence: 99%

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1α,25‐Dihydroxyvitamin D₃ increases IGF binding protein‐5 expression in cultured osteoblasts

et al. 1996

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Insulin-like growth factor binding proteins localize to discrete cell culture compartments in periosteal and osteoblast cultures from fetal rat bone

Chen

Shu

et al. 1998

J. Cell. Biochem.

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Insulin-like growth factor (IGF)-I and IGF-II are expressed at biologically effective levels by bone cells. Their stability and activity are modulated by coexpression of IGF binding proteins (IGFBPs). Secreted IGFBPs may partition to soluble, cell-associated, and matrix-bound compartments. Extracellular localization may sequester, store, or present IGFs to appropriate receptors. Of the six IGFBPs known, rat osteoblasts synthesize all but IGFBP-1. Of these, IGFBP-3, -4, and -5 mRNAs are induced by an increase in cAMP. Little is known about extracellular IGFBP localization in bone and nothing about IGFBP expression by nonosteoblastic periosteal bone cells. We compared basal IGFBP expression in periosteal and osteoblast bone cell cultures and assessed the effects of changes in cAMP-dependent protein kinase A or protein kinase C. Basal IGFBP gene expression differed principally in that more IGFBP-2 and -5 occurred in osteoblast cultures, and more IGFBP-3 and -6 occurred in periosteal cultures. An increase in cAMP enhanced IGFBP-3, -4, and -5 mRNAand accordingly increased soluble IGFBP-3, -4, and -5 and matrix-bound IGFBP-3 and -5 in both bone cell populations. In contrast, protein kinase C activators suppressed IGFBP-5 mRNA, and its basal protein levels remained very low. We also detected low Mr bands reactive with antisera to IGFBP-2, -3, and -5, suggesting proteolytic processing or degradation. Our studies reveal that various bone cell populations secrete and bind IGFBPs in selective ways. Importantly, inhibitory IGFBP-4 does not significantly accumulate in cell-associated compartments, even though its secretion is enhanced by cAMP. Because IGFBPs bind IGFs less tightly in cell-bound compartments, they may prolong anabolic effects by agents that increase bone cell cAMP.

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Intact insulin-like growth factor binding protein-5 (IGFBP-5) associates with bone matrix and the soluble fragments of IGFBP-5 accumulated in culture medium of neonatal mouse calvariae by parathyroid hormone and prostaglandin E2-treatment

et al. 1996

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We examined the distribution of insulin-like growth factor binding proteins (IGFBPs) in cultured neonatal mouse calvariae. IGFBP-3 and -4 were predominantly found in the conditioned medium. IGFBP-2 was partitioned between conditioned medium and bone and extracellular matrix (BECM), while intact (31-kDa) IGFBP-5 was most abundant in BECM extracts. After treatment with parathyroid hormone (PTH, 10(-8) M) or prostaglandin E2 (PGE2, 10(-6) M), immunoreactive IGFBP-5 accumulated in the conditioned medium in a 21-kDa form which did not bind IGF-I on Western ligand blots. PTH and PGE2 did not alter the level of steady-state IGFBP-5 mRNA, nor markedly stimulate IGFBP-5 synthesis in the calvariae, and thus accumulation of 21-kDa IGFBP-5 was largely due to release from BECM. This accumulation of truncated IGFBP-5 in the conditioned medium was not dependent on osteoclastic bone resorption, since it was not blocked by calcitonin or a bisphosphonate which inhibited PTH- and PGE2-stimulated 45Ca-release. The conditioned medium from PTH- or PGE2-treated cultures degraded recombinant human IGFBP-5 into lower molecular weight fragments. Addition of IGF-1 at 10(-8) M into the culture resulted in accumulation of native 31-kDa IGFBP-5. However, even in the presence of IGF-1, the native IGFBP-5 was degraded and the 21-kDa product accumulated in the culture medium. These results suggested a possible proteolytic mechanism for 21-kDa IGFBP-5 accumulation, responsive to PTH and PGE2. Aprotinin, leupeptin, cystatin, and bestatin did not inhibit the effects of PTH and PGE2 in the cultures. The localization of IGFBP-5 in BECM and its release and proteolysis induced by PTH and PGE2 could play a role in the local regulation of bone metabolism.

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Growth hormone and parathyroid hormone stimulate IGFBP-3 in rat osteoblasts

Cited by 33 publications

References 34 publications

1α,25‐Dihydroxyvitamin D₃ increases IGF binding protein‐5 expression in cultured osteoblasts

1α,25‐Dihydroxyvitamin D₃ increases IGF binding protein‐5 expression in cultured osteoblasts

Insulin-like growth factor binding proteins localize to discrete cell culture compartments in periosteal and osteoblast cultures from fetal rat bone

Intact insulin-like growth factor binding protein-5 (IGFBP-5) associates with bone matrix and the soluble fragments of IGFBP-5 accumulated in culture medium of neonatal mouse calvariae by parathyroid hormone and prostaglandin E2-treatment

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Growth hormone and parathyroid hormone stimulate IGFBP-3 in rat osteoblasts

Cited by 33 publications

References 34 publications

1α,25‐Dihydroxyvitamin D3 increases IGF binding protein‐5 expression in cultured osteoblasts

1α,25‐Dihydroxyvitamin D3 increases IGF binding protein‐5 expression in cultured osteoblasts

Insulin-like growth factor binding proteins localize to discrete cell culture compartments in periosteal and osteoblast cultures from fetal rat bone

Intact insulin-like growth factor binding protein-5 (IGFBP-5) associates with bone matrix and the soluble fragments of IGFBP-5 accumulated in culture medium of neonatal mouse calvariae by parathyroid hormone and prostaglandin E2-treatment

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1α,25‐Dihydroxyvitamin D₃ increases IGF binding protein‐5 expression in cultured osteoblasts

1α,25‐Dihydroxyvitamin D₃ increases IGF binding protein‐5 expression in cultured osteoblasts