Effect of bovine serum albumin on the synthesis of prostaglandin and incorporation of (/sup 3/H)acetate into platelet-activating factor
The binding of fatty acids by bovine serum albumin (BSA) is well documented. However, the interaction between the synthesis of prostaglandins (PGs) and the trapping of arachidonate released from cellular lipid stores is not as well understood. In this communication, we relate the trapping of fatty acids to the synthesis of PGs and the incorporation of (/sup 3/H)acetate into platelet-activating factor (PAF). Our results show that, as determined by radioimmunoassay, BSA inhibits bradykinin (BK) (5 ng/ml) and ionophore A23187 (10 microM)-stimulated synthesis of PGs in human embryo lung fibroblasts (IMR-90) in a concentration-dependent manner. Experiments using prelabel with (/sup 3/H)arachidonate followed by extraction and thin-layer chromatography show that, in the presence of 2 mg/ml BSA, IMR-90 release essentially only fatty acid following stimulation with bradykinin. Little if any prostaglandin and no endoperoxide are detected. In the same experiment, in absence of BSA, about 70% of the released label is detected as prostaglandin. alpha-Cyclodextrin, another trapper of fatty acid, inhibits PG synthesis in much the same way. BSA and alpha-cyclodextrin also inhibit prostacyclin synthesis in endothelial cells derived from the calf pulmonary artery. However, the inhibition of PG synthesis in these cells is not as complete as that in the IMR-90. In contrast to the effect of the trappers on PG synthesis, BSA and alpha-cyclodextrin are observed to potentiate BK- and ionophore-stimulated incorporation of (3H)acetate into PAF in the endothelial cells. The labeled PAF is not released from the cells in either the presence or absence of the trappers, leading us to conclude that BSA causes an increase in acetate-labeled cellular PAF by trapping released fatty acid.
- Research Organization:
- Boston Univ. School of Medicine, MA
- OSTI ID:
- 5842152
- Journal Information:
- Arch. Biochem. Biophys.; (United States), Vol. 257:2
- Country of Publication:
- United States
- Language:
- English
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BIOLOGICAL FUNCTIONS
BLOOD COAGULATION FACTORS
BIOSYNTHESIS
CARBOXYLIC ACIDS
BIOCHEMICAL REACTION KINETICS
PROSTAGLANDINS
ACETATES
ARACHIDONIC ACID
BRADYKININ
CATTLE
DOSE-RESPONSE RELATIONSHIPS
EMBRYOS
FIBROBLASTS
LUNGS
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THIN-LAYER CHROMATOGRAPHY
TRITIUM COMPOUNDS
ANIMAL CELLS
ANIMALS
BODY
CARBOXYLIC ACID SALTS
CHROMATOGRAPHY
COAGULANTS
CONNECTIVE TISSUE CELLS
DOMESTIC ANIMALS
DRUGS
FUNCTIONS
HEMATOLOGIC AGENTS
IMMUNOASSAY
IMMUNOLOGY
ISOTOPE APPLICATIONS
KINETICS
KININS
LABELLED COMPOUNDS
MAMMALS
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
POLYPEPTIDES
PRIMATES
PROTEINS
RADIOASSAY
RADIOIMMUNOLOGY
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SOMATIC CELLS
SYNTHESIS
TRACER TECHNIQUES
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550201* - Biochemistry- Tracer Techniques