Energetics of sugar transport by isolated intestinal epithelial cells: effects of cytochalasin B

Journal Article · Mon Jan 01 04:00:00 EST 1979 · Am. J. Physiol.; (United States)

OSTI ID:6621859

Kimmich, G A; Randles, J

The capability of isolated intestinal epithelial cells to establish concentration gradients of 3-O-methylglucose (3-OMG) by a Na/sup +/-dependent transport system is limited by concomitant function of a Na/sup +/-independent, facilitated diffusion transport system. Monosaccharides accumulated by the active system are continuously lost via the passive system, which acts to lower steady-state sugar gradients maintained by the cell. Cytochalasin B is a potent inhibitor of the passive system and allows the cells to establish a sugar gradient that is much higher than normal. When extracellular (3-OMG) is 1 mM, cytochalasin induces sugar accumulation ratios of 30-fold (+- phlorizin) in contrast to control ratios of approximately 10-fold. When (3-OMG) is 0.1 mM, cytochalasin (0.1 mM) induces 40-fold accumulation ratios. When changes in extracellular sugar concentration are considered, steady-state concentration gradients observed are 70-fold. For a Na:sugar coupling stoichiometry of 1:1, gradients of this magnitude represent the approximate theoretical maximum for a transport system driven exclusively by the transmembrane electrochemical potential for Na/sup +/.

• Research Organization: Univ. of Rochester Medical Center, NY
• OSTI ID: 6621859
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 6:1; ISSN AJPHA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
ANIMAL TISSUES
BIOCHEMICAL REACTION KINETICS
BODY
CARBOHYDRATES
CELL CONSTITUENTS
CELL MEMBRANES
ELECTRIC POTENTIAL
EPITHELIUM
GLUCOSE
HEXOSES
KINETICS
MEMBRANE TRANSPORT
MEMBRANES
METABOLISM
METABOLITES
MONOSACCHARIDES
ORGANIC COMPOUNDS
QUANTITY RATIO
REACTION KINETICS
RESPONSE MODIFYING FACTORS
SACCHARIDES
TISSUES