Modelling the glucose-insulin system as a basis for the artificial beta cell.

The control constants for glucose-dependent insulin dosage in diabetic dogs were determined from test results in the opened system on the basis of a global blood glucose plasma-insulin control model. The controlled plant of the model consisted of the glucose and insulin subsystems; the entire insulin providing process was considered to be the controlling element, and the glucose-dependent insulin dose estimation, the controller. The constants obtained were employed in the extracorporeal artificial beta cell. The structure of the model and the numerical values of its state variables were verified by the prediction of blood glucose responses to intravenous glucose loads and by the correspondence between glucose balances and insulin doses as calculates and those as observed in diabetic animals. The application of the optimum control constant estimates in feedback-controlled insulin infusions provides improved blood glucose patterns but unchanged needs for insulin in comparison to the application of standard control parameters.