Calcified Tissue International

, Volume 34, Issue 1, pp 59–66

Alkaline phosphatase inhibition by parathyroid hormone and isoproterenol in a clonal rat osteosarcoma cell line. Possible mediation by cyclic AMP

  • Robert J. Majeska
  • Gideon A. Rodan

DOI: 10.1007/BF02411210

Cite this article as:
Majeska, R.J. & Rodan, G.A. Calcif Tissue Int (1982) 34: 59. doi:10.1007/BF02411210


The effect of parathyroid hormone (PTH 1–34 bovine) on alkaline phosphatase activity was investigated in an osteoblast-like clonal cell line derived from rat osteosarcoma (ROS 17/2). ROS 17/2 alkaline phosphatase resembled the bone enzyme in levamisole sensitivity and electrophoretic mobility but differed in heat stability. The specific activity of ROS 17/2 alkaline phosphatase increased with time in culture. This increase was inhibited by PTH (1–34) and (-)-isoproterenol in a dose-dependent manner starting at near-physiological hormone concentrations. The ID50 values were 0.02 nM for PTH (1–34) and 1.7 nM for isoproterenol. The two hormones stimulated ROS 17/2 adenylate cyclase, albeit at higher concentrations: Km values were 13 nM for PTH (1–34) and 16 nM for isoproterenol. The rise in alkaline phosphatase was also inhibited by dibutyryl cyclic AMP and 8-bromocyclic AMP (0.1 mM). These findings further document the osteoblastic properties of the ROS 17/2 osteosarcoma cell line, suggest that PTH inhibition of alkaline phosphatase represents a physiological response to the hormone in these cells, and implicate cyclic AMP as a mediator of this PTH effect.

Key words

Parathyroid hormoneAlkaline phosphataseCyclic AMPOsteosarcoma

Copyright information

© Springer-Verlag 1982

Authors and Affiliations

  • Robert J. Majeska
    • 1
  • Gideon A. Rodan
    • 1
  1. 1.Department of Oral BiologyUniversity of Connecticut, School of Dental MedicineFarmingtonUSA