Madaus S, Schusdziarra V, Seufferlein T, Classen M
Department of Internal Medicine II, Technical University of Munich, Germany.
Z Gastroenterol. 1989 Sep;27(9):449-54.
In the present study the effects of gastrin-releasing peptide (GRP1-27), its C-terminal decapeptide neuromedin-C (GRP18-27) and the related peptide neuromedin-B were examined on the secretion of gastrin and somatostatin-like immunoreactivity (SLI) from the isolated perfused rat stomach at intraluminal pH 7 or pH 2. GRP1-27 and GRP18-27 stimulated gastrin secretion equally effective at concentrations of 10(-10), 10(-9), 10(-8), 10(-7) and 10(6)M at luminal pH 7. In addition neuromedin-B was tested at 10(-11), 10(-10), 10(-8) and 10(-6)M and it increased gastrin release similar to equimolar doses of GRP18-27. At luminal pH 2 GRP1-27 stimulated gastrin secretion at 10(-9), 10(-8), 10(-7) and 10(-6)M while GRP18-27 was only effective at 10(-8) and 10(-7)M. Neuromedin-B elicited a gastrin increase at 10(-8)M similar to GRP18-27 and also at 10(-6)M. All three peptides had no significant effect on SLI release at luminal pH 7. At luminal pH 2 GRP1-27 at 10(-9)M and 10(-6)M and GRP18-27 and neuromedin-B at 10(-10)M elicited a significant stimulation of SLI secretion. These data demonstrate that all three bombesin-like peptides GRP1-27, GRP18-27 and neuromedin-B can stimulate gastrin release at either a neutral or an acidic luminal pH, while SLI release is affected only at an acidic intragastric milieu. This suggests that all three forms of bombesin-like peptides are good candidates for the peptidergic regulation of gastrin release in the rat stomach, while their role in somatostatin release seems to be more restricted.
在本研究中，检测了胃泌素释放肽（GRP1 - 27）、其C末端十肽神经介素 - C（GRP18 - 27）以及相关肽神经介素 - B对腔内pH值为7或pH值为2的离体灌注大鼠胃中胃泌素和生长抑素样免疫反应性（SLI）分泌的影响。在腔内pH值为7时，GRP1 - 27和GRP18 - 27在浓度为10(-10)、10(-9)、10(-8)、10(-7)和10(6)M时对胃泌素分泌的刺激效果相同。此外，对神经介素 - B在10(-11)、10(-10)、10(-8)和10(-6)M浓度下进行了测试，其增加胃泌素释放的效果与等摩尔剂量的GRP18 - 27相似。在腔内pH值为2时，GRP1 - 27在10(-9)、10(-8)、10(-7)和10(-6)M浓度下刺激胃泌素分泌，而GRP18 - 27仅在10(-8)和10(-7)M浓度下有效。神经介素 - B在10(-8)M时引起的胃泌素增加与GRP18 - 27相似，在10(-6)M时也有此作用。这三种肽在腔内pH值为7时对SLI释放均无显著影响。在腔内pH值为2时，10(-9)M和10(-6)M的GRP1 - 27以及10(-10)M的GRP18 - 27和神经介素 - B均引起SLI分泌的显著刺激。这些数据表明，所有三种铃蟾素样肽GRP1 - 27、GRP18 - 27和神经介素 - B在中性或酸性腔内pH值时均可刺激胃泌素释放，而SLI释放仅在酸性胃内环境中受到影响。这表明所有三种形式的铃蟾素样肽都是大鼠胃中胃泌素释放肽能调节的良好候选者，而它们在生长抑素释放中的作用似乎更为局限。
