Calcitonin Receptors of Human Osteoclastoma

G. C. Nicholson; M. A. Horton; P. M. Sexton; C. S. D'Santos; J. M. Moseley; B. E. Kemp; J. A. S. Pringle; T. J. Martin

doi:10.1055/s-2007-1011887

Hormone and Metabolic Research, Table of Contents

Horm Metab Res 1987; 19(11): 585-589
DOI: 10.1055/s-2007-1011887

Clinical

Calcitonin Receptors of Human Osteoclastoma

G. C. Nicholson¹ , M. A. Horton² , P. M. Sexton¹ , C. S. D'Santos¹ , J. M. Moseley¹ , B. E. Kemp¹ , J. A. S. Pringle³ , T. J. Martin¹

¹University of Melbourne, Department of Medicine, Repatriation General Hospital, Heidelberg, Victoria, Australia
²I.C.R.F. Haemopoiesis Group, Department of Histopathology, St. Bartholomew's Hospital, West Smithfield, London, United Kingdom
³Department of Morbic Anatomy, Royal National Orthopaedic Hospital, Stanmore, Middlesex, United Kingdom

Abstract

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Summary

Osteoclast-rich cultures were prepared by disaggregation of osteoclastomas (giant cell tumour of bone) and settlement onto glass or plastic surfaces. Autoradiography using [¹²⁵I]-salmon calcitonin ([¹²⁵I]-sCT) revealed specific binding only to multinucleate giant cells (osteoclasts) and a minor population of mononuclear cells. [¹²⁵I]-sCT competitive binding studies indicated a K_d of 5 × 10^-10M and receptor number of approximately 1 million sites/osteoclast. sCT treatment resulted in a dose-dependent rise in cAMP (EC₅₀ 10^-10M). Homogenates of an osteoclastoma also demonstrated specific binding of [¹²⁵I]-sCT. Chemical cross-linking of a labelled synthetic sCT derivative, [¹²⁵I]-[Arg^11,18, Lys¹⁴]-sCT, using disuccinimidyl suberate, resulted in labelling of a receptor component of approximate M_r 85-90,000. The multinucleate giant cells (osteoclasts) of human osteoclastomas possess large number of CT receptors which exhibit the same binding kinetics and apparent M_r as those of other CT target cells.

Key-Words

Calcitonin - Receptor - Osteoclastoma - Osteoclast - Autoradiography - Cyclic AMP - Cross-linking

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