Identification of leukotriene D4 specific binding sites in the membrane preparation isolated from guinea pig lung
A radioligand binding assay has been established to study leukotriene specific binding sites in the guinea pig and rabbit tissues. Using high specific activity (/sup 3/H)-leukotriene D4 (( /sup 3/H)-LTD4), in the presence or absence of unlabeled LTD4, the diastereoisomer of LTD4 (5R,6S-LTD4), leukotriene E4 (LTE4) and the end-organ antagonist, FPL 55712, the authors have identified specific binding sites for (/sup 3/H)-LTD4 in the crude membrane fraction isolated from guinea pig lung. The time required for (/sup 3/H)-LTD4 binding to reach equilibrium was approximately 20 to 25 min at 37 degrees C in the presence of 10 mM Tris-HCl buffer (pH 7.5) containing 150 mM NaCl. The binding of (/sup 3/H)-LTD4 to the specific sites was saturable, reversible and stereospecific. The maximal number of binding sites (Bmax), derived from Scatchard analysis, was approximately 320 +/- 200 fmol per mg of crude membrane protein. The dissociation constants, derived from kinetic and saturation analyses, were 9.7 nM and 5 +/- 4 nM, respectively. The specific binding sites could not be detected in the crude membrane fraction prepared from guinea pig ileum, brain and liver, or rabbit lung, trachea, ileum and uterus. In radioligand competition experiments, LTD4, FPL 55712 and 5R,6S-LTD4 competed with (/sup 3/H)-LTD4. The metabolic inhibitors of arachidonic acid and SKF 88046, an antagonist of the indirectly-mediated actions of LTD4, did not significantly compete with (/sup 3/H)-LTD4 at the specific binding sites. These correlations indicated that these specific binding sites may be the putative leukotriene receptors in the guinea-pig lung.
- Research Organization:
- Smith Kline and French Labs., Philadelphia, PA
- OSTI ID:
- 5655782
- Journal Information:
- Prostaglandins; (United States), Journal Name: Prostaglandins; (United States) Vol. 28:6; ISSN PRGLB
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ANIMALS
ARACHIDONIC ACID
BIOCHEMICAL REACTION KINETICS
BODY
BRAIN
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CELL MEMBRANES
CENTRAL NERVOUS SYSTEM
CHEMICAL BONDS
DIGESTIVE SYSTEM
FEMALE GENITALS
GASTROINTESTINAL TRACT
GLANDS
GUINEA PIGS
INTESTINES
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LIGANDS
LIVER
LUNGS
MAMMALS
MEMBRANES
METABOLITES
MONOCARBOXYLIC ACIDS
NERVOUS SYSTEM
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
RABBITS
REACTION KINETICS
RECEPTORS
RESPIRATORY SYSTEM
RODENTS
SMALL INTESTINE
TRACER TECHNIQUES
TRACHEA
TRITIUM COMPOUNDS
UTERUS
VERTEBRATES