SimThyr SimThyr
Ruhr-Universität Bochum

SimThyr, a simulator of thyrotropic feedback control, here on Windows XP, supports a wide range of hardware and operating systems.
SimThyr, a simulator of thyrotropic feedback control, here on Mac OS X 10.6 (Snow Leopard) supports a wide range of hardware and operating systems.

Thyroid hormones play an essential role for metabolism, growth and differentiation. Therefore, exact regulation of thyroid hormone levels is vital for most organisms.

Although the principles of thyrotropic feedback control have been described decades ago we still have not yet gained a comprehensive understanding of its dynamics.

Recently, significant progress has been made with mathematical modelling of thyroid homeostasis. However, due to nonlinear interactions, these cybernetic modells cannot simultaneously describe static and dynamic behaviour. This gap may be filled with computer simulations that additionally facilitate an intuitive insight into the dynamics of thyrotropic feedback.

SimThyr is a simulation program for the pituitary thyroid feedback control that is based on a parametrically isomorphic model of the overall system. Applications of this program cover research, including development of hypotheses, and education of students in biology and medicine, nurses and patients.

SimThyr helped do prove a new hypothesis about the emergence of pulsatile TSH release. Other research projects used SimThyr to investigate the effects of certain structure parameters of the feedback loop on diagnostic quality in the evaluation of thyroid function. Furthermore, the software is used for educational processes at several locations.

The algorithms underlying the continuous simulation process have been released in several publications. They may also be applied in form of classical mathematical modelling, however using them in a computer simulation provides a deeper and more intuitive insight into temporal dynamics of thyroid homeostasis.

Over the previous years, SimThyr has received several certificates and awards.

This is a free application that is offered on the base of a BSD licence. Binaries are available for Mac OS, Mac OS X and Windows, sourcecode requires THINK Pascal (for Mac OS Classic) or Lazarus/Free Pascal (for Mac OS X, Windows and Linux).

SimThyr on Windows XP
SimThyr on Mac OS X 10.4 (Tiger)
SimThyr on Mac OS X 10.5 (Leopard)

SimThyr project entry at