Leukotriene E4 binds specifically to LTD4 receptors in guinea pig lung membranes.
High affinity, stereoselective binding sites for [3H]leukotriene E4 ([3H]LTE4) have been identified and characterized in guinea pig lung membranes. [3H]LTE4 bound to these membranes with a pharmacological specificity identical to that previously observed for the [3H]LTD4 receptor in guinea pig lung. [3H]LTE4 specific binding was selectively inhibited by Na+, enhanced by Ca2+, Mg2+ and Mn2+ and modulated by guanine nucleotides. Scatchard analysis of saturation binding data showed a single class of high affinity and saturable binding sites, with a dissociation constant (Kd) of 0.4 +/- 0.2 nM and a density (Bmax) of 430 +/- 50 fmol/mg membrane protein, similar to values observed for the LTD4 receptor in guinea pig lung. The rank order potency of agonist binding to the [3H]LTE4 binding sites was LTD4 greater than LTE4 much greater than LTC4. These results indicate that [3H]LTE4 binds to [3H]LTD4 receptors and suggests that induction of smooth muscle contraction by LTD4 and LTE4 may be mediated by identical mechanisms and receptors in the guinea pig lung.
Mong
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Scott
M O
MO
Lewis
M A
MA
Wu
H L
HL
Hogaboom
G K
GK
Clark
M A
MA
Crooke
S T
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D000818:Animals; D002021:Buffers; D002118:Calcium / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D004492:Edetic Acid / Q000494:pharmacology; D006150:Guanine Nucleotides / Q000494:pharmacology; D006168:Guinea Pigs; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D017999:Leukotriene E4; D008168:Lung / Q000378:metabolism*; D008297:Male; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018077:Receptors, Leukotriene; D011982:Receptors, Prostaglandin / Q000378:metabolism*; D013189:SRS-A / Q000031:analogs & derivatives* / Q000378:metabolism; D012964:Sodium / Q000494:pharmacology; D014316:Tritium
D002021:Buffers; D006150:Guanine Nucleotides; D011956:Receptors, Cell Surface; D018077:Receptors, Leukotriene; D011982:Receptors, Prostaglandin; D013189:SRS-A; D014316:Tritium; D017999:Leukotriene E4; D004492:Edetic Acid; D012964:Sodium; D002118:Calcium