Limit cycles in the model of hypothalamic-pituitary-adrenal axis activity

Abstract

Oscillatory behavior in a three-dimensional system of differential equations which represents a sub-network of the model of hypothalamic-pituirary-adrenal axes activity is analysed. We show that Hopf bifurcations and degenerate Hopf bifurcations (Bautin bifurcations) can occur in the system for chemically relevant values of parameters, so the system can have two limit cycles.