Preliminary studies had indicated the usefulness of a simplified model of the blood-glucose regulatory system in predicting the response to an oral load. Analog simulations have been performed to test inherent approximations and to determine the relative importance of some of the biological mechanisms involved in this regulation. The effect of the form used for intestinal glucose absorption was examined in this report. Three levels of approximation were simulated and evaluated in terms of physiological similarity and control system response. For some simulated conditions, absorptive parameters could be shown to mask intrinsic characteristics of the glucose-hormonal control system that might be reflected in the response to an oral glucose-tolerance test. However, for parameters in the normal range and appropriately sized glucose loads, a small (four to seven) number of measurements sufficiently characterized the glucose response.