Thyroid hormones play an
essential role in metabolism, growth
and differentiation. As pleiotropic
hormones they profoundly affect the
development and function of nearly
every tissue. It is therefore vital
for most vertebrate organisms that
the concentrations of thyroid
hormones are controlled in an exact
way in line with current
physiological demands.
Although the principles of
thyrotropic
feedback control have been
described decades ago, we have still not yet
gained a comprehensive understanding
of its dynamics.ecently, significant
progress has been made with
mathematical modelling of thyroid
homeostasis. However, due to
nonlinear interactions, these
cybernetic models cannot
simultaneously describe the static
and dynamic behaviour of the
processing structure. This gap may
be filled with computer simulations
that additionally provide more
intuitive insight into the dynamics
of thyrotropic feedback.
SimThyr is an interactive
simulation program of
pituitary-thyroid feedback control
that enables one to study the
relationship between structure and
behaviour of thyroid homeostasis,
i.e. between the architecture of
the intercausal network and the
resulting hormone levels. Its goal
is to support both science and
education in thyroidology.
SimThyr is based on a
parametrically isomorphic model of
the overall system. It is,
therefore, able to bridge the
translational gap between
molecular biology and
comprehensive dynamics on a global level of the
organism. Applications
of this program cover research,
including the development of
hypotheses, and education
of students in biology and
medicine, nurses and patients.
SimThyr has significantly
contributed to research on thyroid
homeostasis. It helped to prove a new
hypothesis about the emergence of pulsatile TSH
release and it delivered key
indications that central hyperdeiodination
leads to low T3 syndrome in humans.
Additionally, it suggested the existence of
epigenetic effects of
thyroid status on central homeostasis.
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 projects at several
locations.
The algorithms underlying the
continuous simulation process have been
released in several publications.
Although they may also be applied in the
form of classical mathematical modelling, studying 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.
SimThyr is a free and open source
application that is offered on the base of a
BSD licence. Binaries are available for
macOS and Windows, source code requires
THINK Pascal (for Mac OS Classic) or
Lazarus/Free Pascal (for Mac OS X, Windows
and Linux).
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