Figure 3 summarizes the integrated roles of the kidney, extrarenal mechanisms, and gastrointestinal effectors in modulating potassium homeostasis. It demonstrates that the undamped increase in plasma K+ in response to potassium administration is progressively attenuated by the adaptive responses by the kidney, by a hierarchy of nonrenal mechanisms including participation by insulin and glucose, and by gastrointestinal mechanisms evoked by GI potassium sensors.