Chacín J, Rincón R, Inciarte D, Cańizales A, Martínez G, Alonso D
Am J Physiol. 1979 Jun;236(6):E692-700. doi: 10.1152/ajpendo.1979.236.6.E692.
An attempt to increase the permeability of gastric mucosa to exogenous Krebs cycle intermediates seemed advisable for a better understanding their relationship with acid secretion. At pH 7.4, citrate, oxoglutarate, fumarate, and malate had no significant effect on oxygen uptake (QO2) nor on acid secretion (QH+) by toad gastric mucosa; succinate increased QO2 slightly and had no effect on QH+; but at pH 5.0, oxoglutarate and succinate increased QO2 by 18 and 21%, respectively. 14CO2 evolved by gastric mucosa incubated with [14C]oxoglutarate, succinate, malate, or citrate was 155, 92, 128, and 353%, respectively, greater at pH 5. Citrate, oxoglutarate, succinate, fumarate, and malate increased QH+ by theophylline-stimulated mucosa at pH 5.0 by 25, 39, 35, 17 and 28%, respectively. Oxoglutarate-dependent respiration was shown to correlate with oxoglutarate oxidation. Malonate and arsenite inhibited QO2 and QH+; malonate inhibition was reversed by washout or by succinate. Arsenite was reversed by washout and accelerated by addition of lipoate immediately after washout. The results suggest that the Krebs cycle has concomitant roles in the regulation of QH+ and oxidative metabolism in the toad gastric mucosa.
为了更好地理解外源性三羧酸循环中间产物与胃酸分泌之间的关系，尝试提高胃黏膜对这些中间产物的通透性似乎是可取的。在pH 7.4时，柠檬酸盐、草酰戊二酸、富马酸盐和苹果酸盐对蟾蜍胃黏膜的氧摄取量（QO2）和胃酸分泌量（QH+）均无显著影响；琥珀酸盐使QO2略有增加，对QH+无影响；但在pH 5.0时，草酰戊二酸和琥珀酸盐分别使QO2增加了18%和21%。与[14C]草酰戊二酸、琥珀酸盐、苹果酸盐或柠檬酸盐一起孵育的胃黏膜所释放的14CO2在pH 5时分别比在pH 7.4时高出155%、92%、128%和353%。在pH 5.0时，柠檬酸盐、草酰戊二酸、琥珀酸盐、富马酸盐和苹果酸盐使茶碱刺激的胃黏膜的QH+分别增加了25%、39%、35%、17%和28%。已证明草酰戊二酸依赖性呼吸与草酰戊二酸氧化相关。丙二酸盐和亚砷酸盐抑制QO2和QH+；通过冲洗或加入琥珀酸盐可逆转丙二酸盐的抑制作用。冲洗可逆转亚砷酸盐的抑制作用，冲洗后立即加入硫辛酸可加速其逆转。结果表明，三羧酸循环在蟾蜍胃黏膜中对QH+和氧化代谢的调节中具有伴随作用。
