NUTRITION METABOLISM OF HIGHER ANIMALS IN HYPOXIA

本研究通过一系列实验研究了低氧对清醒大鼠胃功能的影响。低氧使大鼠尿尿素排泄延迟至低氧12h后，且7.6%O_2低氧组较10.5%O_2低氧组延迟更为显著。实验二，高蛋白饲料喂养大鼠4h后，暴露于7.6%O_2，胃排空延迟。实验3中，在7.6%O_2低氧条件下，正常蛋白质饲料喂养4h的大鼠，其尿素排泄量在低氧24h后才与常氧大鼠有显著性差异。而10.5%O_2缺氧可使正常蛋白质饮食大鼠胃排空延迟。实验4中，高蛋白饲料喂养大鼠4h后，分别暴露于7.6%O_2和10.5%O_2的低氧环境中，6h后7.6%O_2低氧大鼠血浆胃泌素水平是常氧大鼠的2.3倍，而10.5%O_2低氧大鼠血浆胃泌素水平与常氧大鼠无明显差异。此外，在7.6%O_2和10.5%O_2低氧条件下，两组大鼠胃泌素浓度在低氧3h后均高于常氧组。实验5：大鼠幽门结扎后，分别暴露于7.6%O_2和10.5%O_2的低氧环境中3h。缺氧抑制胃酸分泌，促进胃泌素释放。实验6：幽门结扎后禁食大鼠，经口给予盐酸，然后暴露于7.6%O_2缺氧3h。由于缺氧引起的胃泌素浓度的升高被口服盐酸完全抑制。这些结果表明，缺氧抑制胃排空和分泌，缺氧对胃酸分泌的抑制作用通过正反馈调节刺激胃泌素释放。

This study examined the effects of hypoxia on the gastric function in conscious rats in a series of experiments. Hypoxia delayd the excretion rats of urinary urea until after 12h of hypoxia and the delay was more remarkable in rats subjected to 7.6%O_2 hypoxia than in those subjected to 10.5%O_2 hypoxia. In Experiment 2, when rats fed the high protein diet for 4h were exposed to 7.6%O_2, a delay in gastric emptying was found in the hypoxic rats. In Experiment 3, when rats fed the normal protein diet for 4h were exposed to 7.6%O_2 hypoxia, the rats of urea excretion in the hypoxic rats were not significantly different from that in the normoxic rats until after 24h of hypoxia. However, rats fed the normal protein diet for 4h werecaused a delay of gastric emptying by 10.5%O_2 hypoxia. In Experiment 4, when rats fed the high protein diet for 4h were exposed to 7.6%O_2 or 10.5%O_2 hypoxia, the plasma gastrin concentration in the 7.6%O_2 hypoxic rats was 2.3-fold that in the normoxic rats after 6h of hypoxia although the gastrin level did not differ between the 10.5%O_2 hypoxic and the normoxic rats during 6h of hopoxia. Furthermore, when food-deprived rats were exposed to 7.6%O_2 or 10.5%O_2 hypoxia, the gastrin concentration was higher in both hypoxic groups than in the normoxic group after 3h of hypoxia. In Experiment 5, food-deprived rats with pylous ligation were exposed to 7.6%O_2 or 10.5%O_2 hypoxia for 3h. Both hypoxia inhibited the secretion of gastric acid and stimulated the gastrin release. In Experiment 6, food-deprived rats with pylorus ligation were orally administered HC1 and then exposed to 7.6%O_2 hypoxia for 3h. The rise of the gastrin concentration due to hypoxia was completely inhibited by the oral administration of HC1. These results demonstrate that hypoxia inhibits gastric emptying and secretion and that the inhibitory effect of hypoxia on gastric acid secretion stimulates gastrin release through positive feedback regulation.