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A stochastic differential equation model of diurnal cortisol patternsCircadian modulation of episodic bursts is recognized as the normal physiological pattern of diurnal variation in plasma cortisol levels. The primary physiological factors underlying these diurnal patterns are the ultradian timing of secretory events, circadian modulation of the amplitude of secretory events, infusion of the hormone from the adrenal gland into the plasma, and clearance of the hormone from the plasma by the liver. Each measured plasma cortisol level has an error arising from the cortisol immunoassay. We demonstrate that all of these three physiological principles can be succinctly summarized in a single stochastic differential equation plus measurement error model and show that physiologically consistent ranges of the model parameters can be determined from published reports. We summarize the model parameters in terms of the multivariate Gaussian probability density and establish the plausibility of the model with a series of simulation studies. Our framework makes possible a sensitivity analysis in which all model parameters are allowed to vary simultaneously. The model offers an approach for simultaneously representing cortisol's ultradian, circadian, and kinetic properties. Our modeling paradigm provides a framework for simulation studies and data analysis that should be readily adaptable to the analysis of other endocrine hormone systems.
Document ID
20040112590
Document Type
Reprint (Version printed in journal)
Authors
Brown, E. N. (Massachusetts General Hospital Boston, MA 02114, United States)
Meehan, P. M.
Dempster, A. P.
Date Acquired
August 21, 2013
Publication Date
March 1, 2001
Publication Information
Publication: American journal of physiology. Endocrinology and metabolism
Volume: 280
Issue: 3
ISSN: 0193-1849
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: 1-R01-GM-53559
CONTRACT_GRANT: 1-R01-AG-06072
CONTRACT_GRANT: 1-P01-AG-09975
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Space Human Factors
Non-NASA Center