The control of water excretion by anti-diuretic hormone: Some aspects of modelling the system

The antidiuretic-hormone (a.d.h.) controlled water-excretion subsystem of an earlier computer simulation is critically examined in the light of other studies in the area of fluid balance, circulatory control and a.d.h. secretion rate etc. The model forms a convenient framework for the interpretation of a number of studies in terms of a theory of a.d.h. control, and modifications to the earlier model are proposed. It is argued that the concept of an a.d.h. threshold needs clarification, and reasons are suggested as to why nature has placed water excretion under the control of an antidiuretic rather than a diuretic hormone