Experimental data and simulation of cortisol blood levels

Finally, experimental evidence indicates that fluctuations in cortisol secretion are not produced by random processes. In fact, the large inter- and intraindividual variability observed in studies dealing with the effect of fluticasone propionate on cortisol levels [526] may be partly explained with the erratic behavior of the system of (11.12) to (11.15). 

The phase space reconstruction approach, making use only of the hormone plasma profiles, was utilized in order to assess the dimensionality and thus expose the chaotic nature of the underlying dynamics of various hormones. In 

By using methods of nonlinear dynamics, Papavasiliou et al. [539] analyzed the circadian profiles of prolactin, directly from the experimental data, by com- 

From the above studies, it is evident that although significant progress has been made as far as the physiological modeling of hormonal systems is con- 

An important outcome of these studies is the opportunity that it offers to discuss the implications of the presence of nonlinear dynamics in processes such as the secretion of cortisol. Based on the aforementioned discussion it is evident that the concepts of deterministic nonlinear dynamics should be adopted in pharmacodynamic modeling when supported by experimental and physiologic data. This is valid not only for the sake of more detailed study, but mainly because nonlinear dynamics suggest a whole new rationale fundamentally different from the classical approach. Moreover, the clinical pharmacologist should be aware of the limitations of chaotic models for long-term prediction, which is contrary to the routine use of classical models. 

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