In this study, the gas exchange in intestinal tract was observed. Anesthetized rabbits were laparatomized and pouches of duodenum. ileum and colon were framed by ligating two portions of intestinal segment, about 10 cm in length. preserving carefully the normal blood flow in the intestinal pouches. Ten ml. of room air or test gas was injected into each intestinal pouch and composition changes of the gases in the pouches were determined after 1/2, 1. 2. 4 and 6 hours of gas injection.
The volume change of room air was also measured in each pouch at 6th hour after injection of 10ml. of room air.
The composition change of test gas in peritoneal cavity was observed for 4 hours and PO₂and PCO₂of the mesenteric venous blood were measured. Compositions of the intestinal gases(flatus) were analyzed concurrently.
The results obtained were summarized as follows:
1. The concentration of CO₂in the room air injected pouch increased up to about 5% rather abruptly within 1/2 hour of injection and leveled off there after, while O₂decreased exponetially, which is typical in the diffusion phenomena, and reached 1.44% in duodenum, 1.27% in ileum and 2.14% in colon at the 6th hour of injection. The concentration of N_(2) increased to about 93% at the 6th hour.
2. The O₂concentration in test gas injected pouch showed gradual decline and leveled off after 4 hours of injection.
3. During 6 hours followin the injection of 10ml. of air in intestinal pouches, the absorption rate of O₂was 0.33ml./hour in duodenum and ileum and 0.32ml./ hour in colon. And the diffusion capacity of O₂was calculated as 1.63x10^(4)ml./min. mm. Hg. in ileal pouches.
4. Gas tension of tissues facing abdominal cavity was estimated as approximately 46mm.Hg in O₂and 41mm. Hg in CO₂
5. In the intestinal gases, O₂was 1.22% in ileum and 1.44% in colon, CO₂was 5.58% in ileum and 6.44% in colon. The concentration of N_(2) and others was 92%
6. Remarkably lox O₂concentration in the gas of intestinal gas is not directly in contact with the perfusing blood itself but with the epithelial cells of absorptive membrane, which presumable has low intracellular PO₂
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