Regulatory, Integrative and Comparative Physiology

A nonlinear compartmental model of Sr metabolism. II. Its physiological relevance for Ca metabolism

J. F. Staub, E. Foos, B. Courtin, R. Jochemsen, A. M. Perault-Staub


We have studied the peculiarities of the nonlinear compartmental model for human Sr metabolism (Staub JF, Foos E, Courtin B, Jochemsen R, and Perault-Staub AM. Am J Physiol Regul Integr Comp Physiol 284: R819–R834, 2003), including its physiological reliability in the context of Sr-Ca similarity-dissimilarity. We found it to be relevant to Ca metabolism, except for discrimination against Sr relative to Ca at urinary and intestinal levels. The main findings are as follows: 1) the saturable part of intestinal absorption, shared by Sr and Ca, does not seem to be responsible for the discrimination of the transcellular pathway; 2) although there is little discrimination in bone, the physicochemical behaviors of Sr and Ca at the bone surface differ, at least quantitatively; and 3) Sr behaves as a “tracer” for Ca metabolic pathways and, under non-steady-state conditions, can also reveal self-regulatory processes. It is suggested that they depend on Ca2+ (cationic)-sensing receptors that are apparently more sensitive to Sr than to Ca. Acting on gastrointestinal and osteoblast lineage cells, these slow processes might contribute to adaptive, rather than homeostatic, regulation of Ca metabolism. Understanding these features could help clarify the pharmacological and therapeutic effects of oral Sr.

  • strontium administration
  • calcium-strontium discrimination
  • self-regulatory process
  • calcium (cationic)-sensing receptor


  • This study was supported by the Centre National de la Recherche Scientifique and the Institut de Recherches Internationales Servier.

  • Address for reprint requests and other correspondence: J. F. Staub, UMR 7052 Centre National de la Recherche Scientifique, Laboratoire de Recherches Orthopédiques, Faculté de Médecine Lariboisière-St-Louis, 10 Ave. de Verdun, 75010 Paris, France (E-mail:staub{at}

  • The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

  • First published November 7, 2002;10.1152/ajpregu.00228.2002

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