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Activation of Adenosine 3',5'-Monophosphate-Dependent Protein Kinase in Normal and Malignant Bone Cells by Parathyroid Hormone, Prostaglandin E2, and Prostacyclin

Activation of Adenosine 3',5'-Monophosphate-Dependent Protein Kinase in Normal and Malignant Bone... Hormonal activation of cAMP-dependent protein kinase has been studied in cultured cells derived from a rat osteogenic sarcoma and in osteoblast-rich cells grown from newborn rat calvaria. Both cell strains contain adenylate cyclase activities which respond to parathyroid hormone (PTH) and a variety of prostanoids. PTH, prostaglandin E 2 (PGE 2), and prostacyclin (PGI 2) were all capable of activating cAMP-dependent protein kinase (s) in suspensions of the two cell types. Activation was very rapid in all cases, being detectable at 10 sec and maximal between 30–60 sec. Using saturating concentrations of hormones, the protein kinase activity ratio remained elevated (between 0.6–0.9) for up to 35 min after the start of PGE 2 stimulation, but declined toward basal activity ratio 5–10 min after stimulation with PTH or PGI2. Each of the hormones caused a dose-dependent increase in activation of cAMP-dependent protein kinase in both cell types. Half-maximal activation of the enzyme occurred at 2 × 10 -9 M bovine PTH for calvarial cells, at 10-8 M bPTH for osteogenic sarcoma cells, and at 2–4 × 10-8 M PGE22 and 1–3 × 10-7 M PGI22 for both cell types. Maximal activation of protein kinase occurred before maximal cAMP accumulated, implying that only a fraction of cAMP is biologically significant. These two cell strains provide a useful means of analyzing postreceptor events in the hormonal regulation of bone cells. This content is only available as a PDF. Author notes * This work was supported by grants from the Victorian Anti-Cancer Council, the National Health and Medical Research Council, and the Department of Veterans' Affairs. Copyright © 1981 by The Endocrine Society http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Endocrinology Oxford University Press

Activation of Adenosine 3',5'-Monophosphate-Dependent Protein Kinase in Normal and Malignant Bone Cells by Parathyroid Hormone, Prostaglandin E2, and Prostacyclin

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References (21)

Publisher
Oxford University Press
Copyright
Copyright © 1981 by The Endocrine Society
ISSN
0013-7227
eISSN
1945-7170
DOI
10.1210/endo-108-1-220
Publisher site
See Article on Publisher Site

Abstract

Hormonal activation of cAMP-dependent protein kinase has been studied in cultured cells derived from a rat osteogenic sarcoma and in osteoblast-rich cells grown from newborn rat calvaria. Both cell strains contain adenylate cyclase activities which respond to parathyroid hormone (PTH) and a variety of prostanoids. PTH, prostaglandin E 2 (PGE 2), and prostacyclin (PGI 2) were all capable of activating cAMP-dependent protein kinase (s) in suspensions of the two cell types. Activation was very rapid in all cases, being detectable at 10 sec and maximal between 30–60 sec. Using saturating concentrations of hormones, the protein kinase activity ratio remained elevated (between 0.6–0.9) for up to 35 min after the start of PGE 2 stimulation, but declined toward basal activity ratio 5–10 min after stimulation with PTH or PGI2. Each of the hormones caused a dose-dependent increase in activation of cAMP-dependent protein kinase in both cell types. Half-maximal activation of the enzyme occurred at 2 × 10 -9 M bovine PTH for calvarial cells, at 10-8 M bPTH for osteogenic sarcoma cells, and at 2–4 × 10-8 M PGE22 and 1–3 × 10-7 M PGI22 for both cell types. Maximal activation of protein kinase occurred before maximal cAMP accumulated, implying that only a fraction of cAMP is biologically significant. These two cell strains provide a useful means of analyzing postreceptor events in the hormonal regulation of bone cells. This content is only available as a PDF. Author notes * This work was supported by grants from the Victorian Anti-Cancer Council, the National Health and Medical Research Council, and the Department of Veterans' Affairs. Copyright © 1981 by The Endocrine Society

Journal

Endocrinology – Oxford University Press

Published: Jan 1, 1981

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