Dietary potassium modulates active potassium absorption and secretion in rat distal colon

Journal Article · Sat Nov 01 00:00:00 EST 1986 · Am. J. Physiol.; (United States)

OSTI ID:6917507

Foster, E S; Sandle, G I; Hayslett, J P; Binder, H J

To determine the effect of variations in body stores of potassium on the rate of active potassium transport in the large intestine, unidirectional 42K fluxes were performed under short-circuit conditions across isolated distal colonic mucosa of control, dietary potassium-depleted and dietary potassium-loaded rats. Potassium depletion stimulated net potassium absorption (JK net) (0.87 +/- 0.19 vs. 0.49 +/- 0.04 mu eq X h-1 X cm-2, P less than 0.025) due to a 40% increase in mucosal-to-serosal potassium transport (JK m----s). In sodium-free Ringer solution JK net in the potassium-depleted group was also significantly greater than in controls (1.93 +/- 0.26 vs. 1.01 +/- 0.11 mu eq X h-1 X cm-2, P less than 0.005). In contrast, in chloride-free Ringer solution JK net was identical in the control and potassium-depleted groups (0.39 +/- 0.05 vs. 0.46 +/- 0.07 mu eq X h-1 X cm-2, P = NS). Potassium loading reversed net potassium absorption to net potassium secretion (-0.76 +/- 0.08 mu eq X h-1 X cm-2, P less than 0.001) as the result of a decrease in JK m----s and an increase in serosal-to-mucosal potassium transport (JK s----m). Net potassium secretion was abolished in the absence of either sodium or chloride from the bathing solution but not by mucosal amiloride. In sodium-free Ringer solution JK net was similar in control and potassium-loaded groups, respectively.

• Research Organization: Yale Univ. School of Medicine, New Haven, CT
• OSTI ID: 6917507
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States)
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
POTASSIUM
INTESTINAL ABSORPTION
SECRETION
DIET
LARGE INTESTINE
MEMBRANE TRANSPORT
MUCOUS MEMBRANES
POTASSIUM 42
RATS
SODIUM
TRACER TECHNIQUES
ABSORPTION
ALKALI METAL ISOTOPES
ALKALI METALS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
DIGESTIVE SYSTEM
ELEMENTS
GASTROINTESTINAL TRACT
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
INTESTINES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MEMBRANES
METALS
NUCLEI
ODD-ODD NUCLEI
ORGANS
POTASSIUM ISOTOPES
RADIOISOTOPES
RODENTS
UPTAKE
VERTEBRATES
550101* - Behavioral Biology- Tracer Techniques