Endocrinology and the systems paradigm.

Abstract

As endocrinology has matured from its descriptive phase, research on the mechanisms of hormone action has been a major current in the field, and biochemistry has been the paradigm for such research. Systems theory provides a different paradigm for endocrine research, having as its goal computer modelling and simulation of endocrine processes. The presence of feedback in endocrine systems, together with the number and complexity of endocrine interactions, dictates the necessity of computer modelling because of the inadequacies of language to describe complex systems. The modelling of an endocrine system requires information on the dynamic operating characteristics of its various components. The techniques of acquiring and manipulating such information are illustrated by analyzing a simple hydraulic system with feedback regulation, which had once been used as an analog of the pituitary-adrenocortical system. Then the current modelling of two intrinsically nonlinear components of the pituitary-adrenocortical system is described in tutorial fashion, with references to the primary literature. The approach and emphasis is strongly physical, contrasting with the previous character of endocrine research.