Active K transport across rabbit distal colon: relation to Na absorption and Cl secretion

Journal Article · Fri Aug 01 00:00:00 EDT 1986 · Am. J. Physiol.; (United States)

OSTI ID:6281072

Halm, D R; Frizzell, R A

The authors measured isotopic unidirectional fluxes of K to elucidate the mechanisms of active K transport across the distal colon of the rabbit. Separate pathways for active K absorption and active K secretion were detected using various transport inhibitors and stimulators. The rate and direction of net USK transport depend on the activities of these two pathways. K absorption was reduced by orthovanadate (both solutions) or serosal Ba, consistent with ATPase-dependent uptake of K across the apical membrane and exit via a Ba-sensitive basolateral K conductance. K secretion was inhibited by serosal ouabain or mucosal Ba, indicating that K secretion involves basolateral uptake via the Na-K pump and apical exit via a Ba-sensitive K conductance. Active K secretion appears to be electrogenic, since inhibition by ouabain produced equivalent changes in the net K flux and short-circuit current. Addition of bumetanide to the serosal solution or the removal of either Na or Cl from the serosal solution inhibited K secretion; mucosal solutions amiloride was without effect. These results indicate that this K secretory process is independent of electrogenic Na absorption but is mechanistically similar to TWCl secretory processes. Both epinephrine and prostaglandin E2 (PGE2) stimulate K secretion, but only PGE2 also stimulates Cl secretion. The response to these secretogogues suggest that the mechanisms underlying K and Cl secretion are closely linked but can be regulated independently.

• Research Organization: Univ. of Alabama, Birmingham
• OSTI ID: 6281072
• Journal Information: Am. J. Physiol.; (United States), Vol. 251:2
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CHLORINE 36
SECRETION
POTASSIUM 42
ABSORPTION
MEMBRANE TRANSPORT
POTASSIUM COMPOUNDS
ATP-ASE
LARGE INTESTINE
PHYSIOLOGY
RABBITS
ACID ANHYDRASES
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CHLORINE ISOTOPES
DIGESTIVE SYSTEM
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
GASTROINTESTINAL TRACT
HOURS LIVING RADIOISOTOPES
HYDROLASES
INTERMEDIATE MASS NUCLEI
INTESTINES
ISOTOPES
LIGHT NUCLEI
MAMMALS
NUCLEI
ODD-ODD NUCLEI
ORGANS
PHOSPHOHYDROLASES
POTASSIUM ISOTOPES
RADIOISOTOPES
VERTEBRATES
YEARS LIVING RADIOISOTOPES
551001* - Physiological Systems- Tracer Techniques