Dynamic model of hormonal systems coupled by negative feedback.

Most hormone concentrations in the body are regulated by negative feedback mechanisms in which the production and release of hormones are regulated according to the concentration of related species. Also, it has been observed that several hormones are released in a variety of pulsatile patterns. In most cases, the mechanism driving these complex patterns is not well understood. Our model of two cells coupled through negative feedback to their external products demonstrates periodic, aperiodic and chaotic oscillations. The coupling between the cells seems to be responsible for these dynamic behaviors. The variety of dynamic behaviors observed in the model demonstrates that a simple physiological feedback loop mimicking the coupling between circulatory hormones and production centers could be the source of complex hormone release patterns observed in vivo.