Digitonin abolishes free 2-deoxy-D-glucose accumulation in isolated rat adipocytes
The hypothesis that accumulation against sizable chemical gradients of free (non-phosphorylated) 2-deoxy-D-glucose (2dGlc) in isolated rat adipocytes results from an intracellular compartmentation of free hexose was investigated. Cells exposed to 20 ..mu..g/ml digitonin for 10' demonstrated an increased plasma membrane permeability indexed by increased L-glucose entry rates and cellular (presumably cytosolic) protein and K/sup +/ loss. Functional integrity of intracellular organelles was indicated by the ability of the cells to support ATP-driven /sup 45/Ca/sup 2 +/-uptake. Equilibrium 3-O-methylglucose (3-O-MG, a non-accumulated hexose) levels were unaffected. These data suggest a specific permeabilizing action of digitonin at the plasma membrane having no effect on intracellular organelles or passively distributed solutes. Upon addition of digitonin, free 2dGlc fell from 66.5 +/- 8.9 to 7.4 +/- 2.3 pmol/10/sup 5/ cells, a value not significantly different from 3-O-MG levels. The gradient of 2dGlc-phosphate was also abolished, as was the increased steady-state free 2dGlc levels induced by insulin. The data argue against a compartmentation model as either the mechanism of adipocyte sugar accumulation or the basis of the steady-state free 2dGlc increase seen with insulin and suggest that an intact plasma membrane is essential to the process.
- Research Organization:
- Univ. of Pennsylvania, Philadelphia
- OSTI ID:
- 6774601
- Report Number(s):
- CONF-8604222-; TRN: 87-009079
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:4; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
Similar Records
Transport and subcellular distribution characteristics of human erythrocyte glucose transporter fused in adipocytes
Insulin alters cAMP-activated lipolysis but not cAMP-inhibited glycogen synthase in permeabilized adipocytes
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
CELL MEMBRANES
PERMEABILITY
DIGITALIS
BIOLOGICAL EFFECTS
GLUCOSE
MEMBRANE TRANSPORT
METABOLISM
CALCIUM 45
CALCIUM COMPOUNDS
FAT CELLS
RATS
TRACER TECHNIQUES
ALDEHYDES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CALCIUM ISOTOPES
CARBOHYDRATES
CELL CONSTITUENTS
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
EVEN-ODD NUCLEI
HEXOSES
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MEDICINAL PLANTS
MEMBRANES
MONOSACCHARIDES
NUCLEI
ORGANIC COMPOUNDS
PLANTS
RADIOISOTOPES
RODENTS
SACCHARIDES
SOMATIC CELLS
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology
550501 - Metabolism- Tracer Techniques