AJP - Gastrointestinal and Liver Physiology, Vol 247, Issue 5 445-G456, Copyright © 1984 by American Physiological Society
Mechanism and regulation of transcellular potassium transport by the colon
P. L. Smith and R. D. McCabe
The mechanisms by which the colon handles potassium have been the subject
of controversy for several years. However, recent studies have provided
compelling evidence supporting the presence of active transcellular
mechanisms for potassium transport by the colon. These studies have
demonstrated that active uptake mechanisms for potassium exist at both the
apical and basolateral membranes. Thus, depending on the conditions or the
segment of colon studied, both active potassium absorption and secretion
can be demonstrated. In addition, results have been obtained demonstrating
that active potassium transport by the colon is regulated by endogenous
mediators via modulation of intracellular cAMP and/or calcium levels.
However, the mechanisms by which potassium exits across either cell
membrane and the mechanisms by which intracellular mediators regulate
active potassium uptake processes and/or potassium exit are not well
understood.
