Inhibition by amiloride analogues of Na sup + -dependent hexose uptake in LLC-PK sub 1 /Cl sub 4 cells

Journal Article · Sat Aug 01 04:00:00 EDT 1987 · American Journal of Physiology; (USA)

OSTI ID:5060215

Cook, J S; Shaffer, C; Cragoe, Jr, E J ^[1]

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1. Oak Ridge National Laboratory, TN (USA) Merck Sharp and Dohme Research Laboratories, West Point, PA (USA)

Amiloride and four analogues of amiloride were shown to inhibit Na{sup +}-dependent, phlorizin-sensitive hexose uptake by a clone of pig kidney cells, LLC-PK{sub 1}/Cl{sub 4}. The analogues tested were: 5-(N-ethyl-N-isopropyl)amiloride (EIPA), 5-(N-methyl-N-isobutyl)amiloride (MIBA), 3{prime},4{prime}-dichlorobenzamil, and phenamil. The transport substrate was the nonmetabolizable glucose analogue {alpha}-methyl-D-glucoside. Blockade of Na{sup +}-K{sup +} transport at the basolateral membranes or removal of divalent cations from the assay medium had little effect on the initial rate of hexose uptake, whereas MIBA remained an effective inhibitor under both conditions. The inhibitions by EIPA of Na{sup +}-H{sup +} exchange and hexose-dependent Na{sup +} uptake could be distinguished by appropriate choice of concentrations of the inhibitor. Hexose transport inhibition does not appear to be secondary to other known effects of the amilorides. Inhibition by all analogues is enhanced when they are tested in low (2 mM) Na{sup +} medium, where they show half-maximal inhibition in the range of 100-300 {mu}M. More detailed kinetic analysis of inhibition by EIPA shows it to be competitive with Na{sup +} with a K{sub i} of 73-107 {mu}M. It is concluded that the amilorides are acting directly on the hexose transporter.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5060215
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 253:2; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BODY
CARBOHYDRATES
CARBON 14 COMPOUNDS
CHARGED PARTICLES
CHLORIDES
CHLORINE COMPOUNDS
DIURETICS
DRUGS
HALIDES
HALOGEN COMPOUNDS
HEXOSES
INHIBITION
IONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KIDNEYS
KINETICS
LABELLED COMPOUNDS
LIGHT NUCLEI
MONOSACCHARIDES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
RADIOISOTOPES
REACTION KINETICS
SACCHARIDES
SODIUM 22
SODIUM COMPOUNDS
SODIUM ISOTOPES
UPTAKE
YEARS LIVING RADIOISOTOPES