Quite a while back, I posted about the dynamics of the thyroid and its interactions with other systems.
That was a conceptual model; this is a mathematical model. This is a Vensim replication of:
Marisa Eisenberg, Mary Samuels, and Joseph J. DiStefano III
Extensions, Validation, and Clinical Applications of a Feedback Control System Simulator of the Hypothalamo-Pituitary-Thyroid Axis
Background:We upgraded our recent feedback control system (FBCS) simulation model of human thyroid hormone (TH) regulation to include explicit representation of hypothalamic and pituitary dynamics, and up-dated TH distribution and elimination (D&E) parameters. This new model greatly expands the range of clinical and basic science scenarios explorable by computer simulation.
Methods: We quantified the model from pharmacokinetic (PK) and physiological human data and validated it comparatively against several independent clinical data sets. We then explored three contemporary clinical issues with the new model: …
… These results highlight how highly nonlinear feedback in the hypothalamic-pituitary-thyroid axis acts to maintain normal hormone levels, even with severely reduced TSH secretion.
Volume 18, Number 10, 2008
This version is a superset of the authors’ earlier 2006 model, and closely reproduces that with a few parameter changes.
L-T4 Bioequivalence and Hormone Replacement Studies via Feedback Control Simulations
Volume 16, Number 12, 2006
The model is used in:
TSH-Based Protocol, Tablet Instability, and Absorption Effects on L-T4 Bioequivalence
Volume 19, Number 2, 2009
This works with any Vensim version: