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

N. C. Partridge, B. E. Kemp, M. C. Veroni, T. J. Martin

Research output: Contribution to journalArticle

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.

Original languageEnglish (US)
Pages (from-to)220-225
Number of pages6
JournalEndocrinology
Volume108
Issue number1
DOIs
StatePublished - Jan 1981

ASJC Scopus subject areas

  • Endocrinology

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