Tomoi M, Matsuo M, Ono T, Shibayama F
Product Development Laboratories, Fujisawa Pharmaceutical Co., Ltd., Osaka, Japan.
Prostaglandins. 1990 Feb;39(2):113-22. doi: 10.1016/0090-6980(90)90068-7.
The binding of 3H-prostaglandin E2 (PGE2) to rabbit gastric mucosa was investigated. Binding depended on incubation time, temperature and pH, and was saturable and reversible. Scatchard plot analysis revealed a single class of binding sites with a dissociation constant (Kd) of 5.33 +/- 0.21 nM and a maximum number of binding sites (Bmax) of 138.1 +/- 3.4 fmol/mg protein. PGE1 and 16,16-dimethyl PGE2 potently competed with 3H-PGE2 for the binding sites of gastric mucosa, whereas PGA2, PGF2 alpha, 6-keto PGF1 alpha and thromboxane B2 were less potent. The gastric mucosa prepared from the rabbits given indomethacin (5 mg/kg s.c. three times) showed a lower Kd (2.47 +/- 0.19 nM) for 3H-PGE2 than that from untreated one. Treatment with a PGE1 analog, misoprostol (320 micrograms/kg s.c. three times) lowered the Bmax to 74.1 +/- 2.4 fmol/mg protein without any significant effect on the Kd value. It is concluded that rabbit gastric mucosa has specific binding sites for 3H-PGE2 which may be modulated by the levels of PGs in vivo.
研究了³H-前列腺素E2（PGE2）与兔胃黏膜的结合情况。结合作用取决于孵育时间、温度和pH值，具有饱和性和可逆性。Scatchard图分析显示存在一类结合位点，其解离常数（Kd）为5.33±0.21 nM，最大结合位点数（Bmax）为138.1±3.4 fmol/mg蛋白质。PGE1和16,16-二甲基PGE2能有效地与³H-PGE2竞争胃黏膜的结合位点，而PGA2、PGF2α、6-酮基PGF1α和血栓素B2的竞争能力较弱。用吲哚美辛（5 mg/kg皮下注射，每日3次）处理的兔制备的胃黏膜对³H-PGE2的Kd值（2.47±0.19 nM）低于未处理的胃黏膜。用PGE1类似物米索前列醇（320 μg/kg皮下注射，每日3次）处理可使Bmax降至74.1±2.4 fmol/mg蛋白质，而对Kd值无显著影响。结论是兔胃黏膜具有³H-PGE2的特异性结合位点，其可能受体内PGs水平的调节。
