Atwell M M, Hanson P J
Division of Biology, Pharmaceutical Sciences Institute, Aston University, Birmingham, U.K.
Biochim Biophys Acta. 1988 Oct 7;971(3):282-8. doi: 10.1016/0167-4889(88)90143-7.
Rat parietal cells were incubated for 2 h with pertussis toxin (100 ng/ml) which ADP-ribosylates and inactivates guanine nucleotide regulatory proteins (G proteins) of the 'Gi-like' family. The effect of this pretreatment on the action of inhibitors of parietal cell acid secretion was investigated by using the accumulation of the weak base aminopyrine as an index of secretory activity. The inhibitory actions of near maximally effective concentrations of prostaglandin E2 (PGE2), somatostatin and epidermal growth factor (EGF) on histamine-stimulated aminopyrine accumulation were reduced by 83%, 72% and 70%, respectively, by preincubation with pertussis toxin. By contrast, the inhibitory action of a near maximally effective concentration of 12-O-tetradecanoylphorbol 13-acetate on histamine-stimulated aminopyrine accumulation was reduced by only 12%. It is concluded that G-proteins are involved in the inhibitory actions of PGE2, somatostatin and EGF on parietal cells. However, since the inhibitory actions of PGE2 and EGF can be distinguished by the blockade of the action of EGF, but not that of PGE2, by 3-isobutyl-1-methylxanthine, it is possible that PGE2 and EGF either activate the same G-protein in different ways or work through different G-proteins.
将大鼠壁细胞与百日咳毒素（100 ng/ml）孵育2小时，该毒素可使“Gi样”家族的鸟嘌呤核苷酸调节蛋白（G蛋白）发生ADP核糖基化并使其失活。通过使用弱碱氨基比林的蓄积作为分泌活性指标，研究了这种预处理对壁细胞酸分泌抑制剂作用的影响。用百日咳毒素预孵育后，前列腺素E2（PGE2）、生长抑素和表皮生长因子（EGF）接近最大有效浓度对组胺刺激的氨基比林蓄积的抑制作用分别降低了83%、72%和70%。相比之下，接近最大有效浓度的12 - O - 十四烷酰佛波醇13 - 乙酸酯对组胺刺激的氨基比林蓄积的抑制作用仅降低了12%。结论是G蛋白参与了PGE2、生长抑素和EGF对壁细胞的抑制作用。然而，由于3 - 异丁基 - 1 - 甲基黄嘌呤可阻断EGF的作用，但不能阻断PGE2的作用，从而区分PGE2和EGF的抑制作用，因此PGE2和EGF可能以不同方式激活相同的G蛋白，或者通过不同的G蛋白发挥作用。
