The renal transport of potassium has been extensively reviewed and analyzed on a number of occasions, but there has been no similar in-depth treatment of intestinal absorption. In this review, we have attempted to elucidate the role of intestinal absorption in K+ homeostasis under normal conditions and when physiology is deranged by disease. Because absorption is determined by dietary K+ intake and intestinal K+ transport processes, both diet and intestinal transport physiology are analyzed. Particular emphasis is placed on the physiological factors that regulate K+ transport, the factors that determine K+ losses in diarrheal disease, and the degree to which the intestine can adapt its absorption and secretion of K+ in response to extraintestinal disease. Much of the data we describe was reported many years ago when metabolic balance studies were in vogue; however, for the most part, this body of knowledge has not previously been used for the present purpose.
