Dexamethasone blocks arachidonate biosynthesis in isolated hepatocytes and cultured hepatoma cells
The effect of dexamethasone on the incorporation and conversion of (1-14C)eicosa-8,11,14-trienoic acid to arachidonic acid in isolated hepatocytes and in hepatoma tissue culture (HTC) cells was studied. In both kinds of cells, no changes in the exogenous acid incorporation were found when the hormone was added to the incubation media at 0.1 or 0.2 mM concentration, while the biosynthesis of arachidonic acid was significantly depressed. The effect on the biosynthesis was faster in isolated normal liver cells (60 min) than in tumoral cells (120 min) and reached an inhibition of ca. 50% after 3 hr of treatment. The addition of cycloheximide (10(-6) M) also caused a marked decrease in the biosynthesis of this polyunsaturated fatty acid, but when dexamethasone was added to the media simultaneously with cycloheximide, a synergistic action was not observed. The results obtained show that protein synthesis would be involved in the modulation of the biosynthesis of arachidonic acid by glucocorticoids. The changes in the delta 5 desaturation of labeled 20:3 omega 6 to arachidonic acid correlated with changes in the fatty acid composition in isolated cells.
- Research Organization:
- Instituto de Investigaciones Bioquimicas de La Plata (INIBIOLP), La Plata, Argentina
- OSTI ID:
- 5576993
- Journal Information:
- Lipids; (United States), Vol. 3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ARACHIDONIC ACID
BIOSYNTHESIS
DEXAMETHASONE
BIOLOGICAL EFFECTS
CYCLOHEXIMIDE
EXPERIMENTAL NEOPLASMS
HEPATOMAS
IN VITRO
KINETICS
LIVER CELLS
RATS
SYNERGISM
TISSUE CULTURES
TUMOR CELLS
ADRENAL HORMONES
ANIMAL CELLS
ANIMALS
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
CARBOXYLIC ACIDS
CORTICOSTEROIDS
DISEASES
DRUGS
FUNGICIDES
GLUCOCORTICOIDS
HORMONES
HYDROXY COMPOUNDS
KETONES
MAMMALS
MONOCARBOXYLIC ACIDS
NEOPLASMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PESTICIDES
PREGNANES
RODENTS
SOMATIC CELLS
STEROID HORMONES
STEROIDS
SYNTHESIS
VERTEBRATES
550901* - Pathology- Tracer Techniques