Uemura N, Dickinson K E, Sekar M C, Hirschowitz B I
Division of Gastroenterology, University of Alabama, Birmingham 35294.
Biochem Biophys Res Commun. 1989 Mar 15;159(2):599-604. doi: 10.1016/0006-291x(89)90036-3.
Bombesin (BB)-stimulated pepsinogen secretion from frog esophageal peptic acini was inhibited 40% by somatostatin (SS) (IC50 = 1 nM), and by 30-50% by low concentrations (10(-7)-10(-4)M) of lanthanum chloride. SS inhibited basal secretion as well as both early (0-2 min) and late (2-30 min) BB-stimulated secretory phases. By contrast, LaCl3 selectively inhibited the late secretory phase and was without effect on basal secretion. SS (100 nM) and LaCl3 (30 microM) attenuated BB-stimulated 45Ca2+ uptake, and the combination resulted in additive inhibition. High K+ media decreased basal secretion, abolished SS but not LaCl3 inhibition of BB-stimulated secretion, and blocked SS inhibition of BB-mediated 45Ca2+ uptake. These findings suggest the existence on peptic cells of distinct La3+-sensitive, and somatostatin-sensitive, K+ dependent, Ca2+ mobilizing mechanisms which contribute to BB receptor-mediated secretion.
蛙食管消化腺泡中蛙皮素（BB）刺激的胃蛋白酶原分泌，被生长抑素（SS）抑制了40%（IC50 = 1 nM），并被低浓度（10⁻⁷ - 10⁻⁴M）的氯化镧抑制了30 - 50%。SS抑制基础分泌以及BB刺激的早期（0 - 2分钟）和晚期（2 - 30分钟）分泌阶段。相比之下，LaCl₃选择性地抑制晚期分泌阶段，对基础分泌无影响。SS（100 nM）和LaCl₃（30 μM）减弱了BB刺激的⁴⁵Ca²⁺摄取，两者联合导致相加性抑制。高钾培养基降低基础分泌，消除了SS对BB刺激分泌的抑制作用，但未消除LaCl₃的抑制作用，并且阻断了SS对BB介导的⁴⁵Ca²⁺摄取的抑制作用。这些发现表明，在消化细胞上存在不同的对La³⁺敏感、对生长抑素敏感、依赖钾离子、动员钙离子的机制，这些机制参与了BB受体介导的分泌。
