A dynamical model for the pulsatile secretion of the hypothalamo-pituitary-adrenal axis

Model Structure

Many hormones are secreted pulsatilely with periods of about one hour. These rhythms are on a different timescale to circadian rhythms, suggesting they are regulated by distinct mechanisms. Neither does it seem likely these hormone oscillations are completely controlled at the molecular or cellular level. Instead, the authors of the model described here suggest they probably originate from system dynamics. They propose a dynamical model for the secretory system of the hypothalamic-pituitary-adrenal (HPA) axis (see the figure below). Comparison of model simulation results with experimental data demonstrate the mathematical model captures the essence of the hormone dynamics.

Schematic diagram of the hormone flow and interactions between the different components of the hypothalamic-pituitary-adrenal (HPA) axis which are described by the mathematical model. CRH represents corticotropin releasing hormone, ACTH represents corticotropin, and CBG is corticosteroid binding globulin. Red arrows represent hormone disposal, while black arrows represent flow between the different glands and plasma. + represents a stimulatory effect while - represents an inhibitory effect.

The complete original paper reference is cited below:

A dynamical model for the pulsatile secretion of the hypothalamo-pituitary-adrenal axis, Yi-Wei Liu, Zhi-Hong Hu, Jian-Hua Peng, and Bing-Zheng Liu, 1999, Mathematical and Computer Modelling , 29, 103-110. (A PDF version of the article is available to journal subscribers on the Mathematical and Computer Modelling website.)