Cyclic AMP and CaS -activated K transport in a human colonic epithelial cell line
Addition of either vasoactive intestinal peptide (VIP) or the CaS ionophore, A23187, to confluent monolayers of the T84 epithelial cell line derived from a human colon carcinoma increased the rate of YWRb or USK efflux from preloaded cells. The effect of A23187 required extracellular CaS , while that of VIP correlated with its known effect on cyclic AMP production. Other agents which increased cyclic AMP production or mimicked its effect also increased YWRb efflux. VIP- or A23187-stimulated efflux was inhibited by 5 mM BaS or 1 mM quinidine, but not by 20 mM tetraethylammonium, 4 mM 4-aminopyridine, or 1 microM apamin. Under appropriate conditions, VIP and A23187 also increased the rate of YWRb or USK uptake. Stimulation of the initial rate of uptake by either agent required high intracellular K and was not markedly affected by the imposition of transcellular pH gradients. The effect of A23187, but not VIP or dibutyryl cyclic AMP, was refractory to depletion of cellular energy stores. A23187-stimulated uptake was not significantly affected by anion substitution, however, stimulation of uptake by VIP required the presence of a permeant anion. This result may be due to the simultaneous activation of a cyclic AMP-dependent Cl transport system. The kinetics of both VIP- and A23187-stimulated uptake and efflux were consistent with a channel-rather than a carrier-mediated K transport mechanism. The results also suggest that cyclic AMP and CaS may activate two different kinds of K transport systems. Finally, both transport systems have been localized to the basolateral membrane of T84 monolayers, a result compatible with their possible regulatory role in hormone-activated electrogenic Cl secretion.
- Research Organization:
- Univ. of California, San Diego
- OSTI ID:
- 6292117
- Journal Information:
- J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 26; ISSN JBCHA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALI METAL ISOTOPES
ALKALI METALS
ALKALINE EARTH METALS
AMP
ANIMAL TISSUES
ANIONS
BARIUM
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BODY
CALCIUM
CARBOHYDRATES
CARCINOMAS
CARDIAC GLYCOSIDES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CATIONS
CELL CONSTITUENTS
CELL MEMBRANES
CHARGED PARTICLES
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DISEASES
DRUGS
ELEMENTS
ENZYME INHIBITORS
EPITHELIUM
GASTROINTESTINAL TRACT
GLYCOSIDES
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
INTESTINES
IONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KINETICS
LARGE INTESTINE
MEMBRANE TRANSPORT
MEMBRANES
METALS
MINUTES LIVING RADIOISOTOPES
NEOPLASMS
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
OUABAIN
POTASSIUM
POTASSIUM 42
POTASSIUM ISOTOPES
RADIOISOTOPES
REACTION KINETICS
RUBIDIUM
RUBIDIUM 86
RUBIDIUM ISOTOPES
SODIUM
STROPHANTHINS
TISSUES
UPTAKE