Uptake of 3-0-methyl-/sup 14/C-D-glucose by rat thymic lymphocytes: insensitivity to cortisol and inhibitors of ribonucleic acid and protein synthesis, and sensitivity to Cytochalasin B

Journal Article · Sun Dec 01 04:00:00 EST 1974 · RES, J. Reticuloendothel. Soc.; (United States)

OSTI ID:7199547

Feldman, M J; Kraetsch, R E; Lichtman, M A; Peck, W A

We have characterized the transport of 3-0-methyl-D-glucose (3-MG) by rat thymic lymphocytes in vitro. The uptake of this nonmetabolizable glucose analog is very rapid, nonconcentrative and appears to share the uptake pathway for D-glucose. Distribution ratios at an apparently steady state of accumulation are consistently less than unity, suggesting exclusion of the sugar from a fraction of cell water. The data were most consistent with 2 mechanisms for 3-MG uptake: a nonsaturable process (simple diffusion) and a saturable process with kinetic parameters characteristic of facilitated diffusion. The latter mechanism predominates at extracellular concentrations of 3-MG less than 5 mM. Treatment of thymocytes for 3 hr with cycloheximide and actinomycin D failed to decrease 3-MG uptake but did impair significantly the accumulation of ..cap alpha..-aminoisobutyric acid (AIB) uptake, which is transported by an active (concentrative) transport mechanism. Cytochalasin B severely reduced 3-MG uptake but not that of AIB. In contrast, cortisol (l..mu..M) inhibited AIB uptake and did not impair 3-MG uptake. The insensitivity of 3-MG accumulation, unlike AIB accumulation, to inhibitors of RNA and protein synthesis suggest that a putative protein carrier(s) involved in facilitated diffusion of sugars might be more stable than those involved in the active transport of amino acids. Alternatively, the sugar transport process may not involve protein. The inability of cortisol to inhibit 3-MG accumulation argues against hexose transport (as opposed to phosphorylation) as a key site of glucocorticoid action on thymic lymphocytes.

• Research Organization: Univ. of Rochester, NY
• OSTI ID: 7199547
• Journal Information: RES, J. Reticuloendothel. Soc.; (United States), Journal Name: RES, J. Reticuloendothel. Soc.; (United States) Vol. 16:6; ISSN RESJA
• Country of Publication: United States
• Language: English

Related Subjects

550600* -- Medicine
551000 -- Physiological Systems
59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
ADRENAL HORMONES
ALDEHYDES
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOCHEMISTRY
BIOLOGICAL MATERIALS
BIOSYNTHESIS
BLOOD
BLOOD CELLS
BODY
BODY FLUIDS
CARBOHYDRATES
CARBON 14
CARBON 14 COMPOUNDS
CARBON ISOTOPES
CHEMISTRY
CONNECTIVE TISSUE CELLS
CORTICOSTEROIDS
EVEN-EVEN NUCLEI
GLUCOCORTICOIDS
GLUCOSE
HEXOSES
HORMONES
HYDROCORTISONE
HYDROXY COMPOUNDS
INHIBITION
ISOTOPES
KETONES
KINETICS
LABELLED COMPOUNDS
LEUKOCYTES
LIGHT NUCLEI
LYMPHATIC SYSTEM
LYMPHOCYTES
MAMMALS
METABOLISM
MONOSACCHARIDES
NUCLEI
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PREGNANES
PROTEINS
RADIOISOTOPES
RATS
REACTION KINETICS
RETICULOENDOTHELIAL SYSTEM
RNA
RODENTS
SACCHARIDES
SOMATIC CELLS
STEROID HORMONES
STEROIDS
SYNTHESIS
THYMOCYTES
THYMUS
TISSUES
UPTAKE
VERTEBRATES
YEARS LIVING RADIOISOTOPES