Effect of the serine-borate complex on the relative ability of leukotriene C₄, D₄ and E₄ to inhibit lung and brain [³H]leukotriene D₄ and [³H]leukotriene C₄ binding: Demonstration of the agonists' potency order for leukotriene D₄ and leukotriene C₄ receptors

To define the potency order of the leukotrienes for inhibition of [³H] leukotriene D₄ and [³H]leukotriene C₄ binding, we investigated leukotriene C₄, D₄ and E₄ competition with and without the serine-borate complex in guinea pig lung and brain homogenates. Without it, the rank order of their potency for inhibition of lung [³H]leukotriene D₄ or [³H]leukotriene C₄ binding was leukotriene C₄ = leukotriene D₄ > leukotriene E₄. Presence of the complex altered the potency order for both competition studies: for the [³H]leukotriene D₄ competition it was leukotriene D₄ > leukotriene E₄ = leukotriene C₄ and for the [³H]leukotriene C₄ competition it was leukotriene C₄ ≫ leukotriene D₄ ≥ leukotriene E₄.