Peptidoleukotrienes: distinct receptors for leukotriene C4 and D4 in the guinea-pig lung.
Using [3H]-leukotriene C4 ([3H]-LTC4) and [3H]-leukotriene D4 ([3H]-LTD4), specific peptidoleukotriene receptors have been identified in membranes derived from guinea-pig lung. In the presence of 0.1 mM guanyl-5'-yl-imidodiphosphate, which completely inhibits [3H]-LTD4 binding, [3H]-LTC4 binding was protein- and temperature-dependent, reached equilibrium within 15 minutes at 20 degrees C and was reversible. Guanine nucleotides had no effect on the [3H]-LTC4 binding. Competition studies with [3H]-LTC4, peptidoleukotrienes C4, D4, E4 and the peptidoleukotriene antagonist FPL 55712 revealed an order of potency of leukotriene C4 much greater than E4 greater than D4 greater than FPL 55712. [3H]-LTD4 competition studies indicated an order of potency of LTD4 greater than LTE4 greater than LTC4 much greater than FPL 55712. Bioconversion of [3H]-LTC4, as determined by high performance liquid chromatography, was less than 3 percent. The data suggest the guinea-pig lung may contain biochemically distinct receptors for LTC4 and LTD4.
D000818:Animals; D001667:Binding, Competitive; D001711:Biotransformation; D002462:Cell Membrane / Q000378:metabolism; D006168:Guinea Pigs; D007700:Kinetics; D008168:Lung / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018077:Receptors, Leukotriene; D013189:SRS-A / Q000378:metabolism*; D014316:Tritium
D011956:Receptors, Cell Surface; D018077:Receptors, Leukotriene; D013189:SRS-A; D014316:Tritium