Medical Neurobiology Commons^™

Aldosterone Stimulates K Secretion Across Mammalian Colon Independent Of Na Absorption, Gerhard Rechkemmer, Dan R. Halm

Neuroscience, Cell Biology & Physiology Faculty Publications

K transport across guinea pig (Cavia porcellus) distal colon was measured in vitro using isotopically determined unidirectional fluxes. Aldosterone stimulated electrogenic Na absorption, as measured by amiloride-sensitive short-circuit current (I_sc), and reduced net K absorption from +2.5 ± 0.2 µEq/cm² per hr to +0.8 ± 0.3 µEq/cm² per hr (mean ± SEM). Amiloride addition to the mucosal solution did not enhance net K absorption, as expected if inhibiting active Na absorption would reduce active K secretion as in the distal nephron. The amiloride-insensitive I_sc was -1.0 ± 0.2 µEq/cm² per hr (mean ± SEM) …