Model-Based Therapeutic Correction of Hypothalamic-Pituitary-Adrenal Axis Dysfunction
Figure 4
A suboptimal but clinically realistic control treatment.
Concentrations of CRH (x1), ACTH (x2), GR (x3) and cortisol (x4) as a function of time in response to a suboptimal but more realistic externally applied perturbation in cortisol u(t). Once again the negative supplement in cortisol signifies a pharmaceutical removal or inactivation of circulating cortisol. Note a less severe reduction in cortisol is applied over a longer period. The corresponding ACTH response is slower but the threshold concentration for cessation of treatment remains the same.