The influence of the form of the periodic function that describes the circadian rhythm on the hypothalamic-pituitary-adrenal (HPA) system self-regulatory activity in humans is discussed. It was found that the HPA system is very sensitive to the choice of this function since it moderates the concentration of all species that are included in the model, as well as the form of ultradian pulses.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200
