Cristol J P, Provençal B, Borgeat P, Sirois P
Department of Pharmacology, Faculty of Medicine, University of Sherbrooke, Quebec, Canada.
J Pharmacol Exp Ther. 1988 Dec;247(3):1199-203.
Specific binding sites for [3H]leukotriene B4 (LTB4) were identified on guinea pig lung macrophages, using high specific activity [3H] LTB4 in the presence or absence of unlabeled LTB4. At 0 degrees C, [3H] LTB4 binding reached equilibrium within 30 min, and addition of a large excess of unlabeled LTB4 resulted in a rapid decrease of specific binding. Binding was saturable, reversible and dependent upon the number of lung macrophages. The KD and Bmax were found to be 3.85 +/- 0.6 nM and 35 +/- 3 fmol/10(6) cells, respectively, as determined from Scatchard analysis. In competition studies for the displacement of [3H]LTB4 from binding sites, LTB4 and its analogs had the following order of potency: LTB4 (Ki = 2.9 +/- 0.8 nM) greater than 5-epi LTB4 (Ki = 58.7 +/- 0.3 nM) greater than 5-deoxy-LTB4 (Ki = 91.7 +/- 0.3 nM) greater than 12-epi LTB4 (Ki = 4.7 +/- 1.2 microM) greater than 5,12-deoxy LTB4 (Ki = 7.6 +/- 0.01 microM) greater than or equal to 12-deoxy LTB4 (Ki = 8.9 +/- 0.01 microM). LTC4 and LTD4 did not displace the [3H] LTB4 binding at concentrations up to 10 microM. [3H]LTB4 was not metabolized during the binding process as determined by reverse-phase high performance liquid chromatography. It was suggested that this binding site might be an LTB4 receptor.
在豚鼠肺巨噬细胞上鉴定出了[3H]白三烯B4（LTB4）的特异性结合位点，实验使用了高比活度的[3H]LTB4，且存在或不存在未标记的LTB4。在0℃时，[3H]LTB4结合在30分钟内达到平衡，加入大量未标记的LTB4会导致特异性结合迅速下降。结合具有饱和性、可逆性，且依赖于肺巨噬细胞的数量。通过Scatchard分析确定，KD和Bmax分别为3.85±0.6 nM和35±3 fmol/10(6)个细胞。在[3H]LTB4结合位点的竞争置换研究中，LTB4及其类似物的效力顺序如下：LTB4（Ki = 2.9±0.8 nM）＞5-表位LTB4（Ki = 58.7±0.3 nM）＞5-脱氧-LTB4（Ki = 91.7±0.3 nM）＞12-表位LTB4（Ki = 4.7±1.2 μM）＞5,12-二脱氧LTB4（Ki = 7.6±0.01 μM）≥12-脱氧LTB4（Ki = 8.9±0.01 μM）。LTC4和LTD4在浓度高达10 μM时不会置换[
