Rattanakul2003_BoneFormation_Estrogenadministration

This a model from the article:
Modeling of bone formation and resorption mediated by parathyroid hormone: response to estrogen/PTH therapy.

Rattanakul C, Lenbury Y, Krishnamara N, Wollkind DJ. Biosystems
2003:70(1):55-72. 12753937
,
Abstract:

Bone, a major reservoir of body calcium, is under the hormonal control of the parathyroid hormone (PTH). Several aspects of its growth, turnover, and mechanism, occur in the absence of gonadal hormones. Sex steroids such as estrogen, nonetheless, play an important role in bone physiology, and are extremely essential to maintain bone balance in adults. In order to provide a basis for understanding the underlying mechanisms of bone remodeling as it is mediated by PTH, we propose here a mathematical model of the process. The nonlinear system model is then utilized to study the temporal effect of PTH as well as the action of estrogen replacement therapy on bone turnover. Analysis of the model is done on the assumption, supported by reported clinical evidence, that the process is characterized by highly diversified dynamics, which warrants the use of singular perturbation arguments. The model is shown to exhibit limit cycle behavior, which can develop into chaotic dynamics for certain ranges of the system's parametric values. Effects of estrogen and PTH administrations are then investigated by extending on the core model. Analysis of the model seems to indicate that the paradoxical observation that intermittent PTH administration causes net bone deposition while continuous administration causes net bone loss, and certain other reported phenomena may be attributed to the highly diversified dynamics which characterizes this nonlinear remodeling process.
About this model: This model represents the third model from the published paper (eqs 38-40). The model has been built on the core model (which describes changes in the concentration of PTH, the number of osteoclasts and the number of osteoblasts) by considering the effects of exogenous Estrogen administration (for a period of 12 days in an interval of 28 days). This model was taken from the CellML repository
and automatically converted to SBML.
The original model was:
rattananakul, lenbury, krishnamara, wollkind. (2003) - version01

The original CellML model was created by:
Lloyd, Catherine, May

[e-mail]
The University of Auckland
Auckland Bioengineering Institute
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