Caspary W F
Res Exp Med (Berl). 1977 Aug 16;171(1):13-24. doi: 10.1007/BF01851584.
Enteric hyperoxaluria and oxalate urolithiasis in patients with ileal resection seem to be caused by intestinal hyperabsorption of oxalate. The mechanism responsible for hyperabsorption of oxalate is not known. Intestinal transport of oxalic acid was therefore examined by an in vitro technique in rat intestine. Oxalic acid was absorbed by a mechanism of simple passive diffusion. The rate of absorption decreased from the colon to the duodenum (colon greater than ileum greater than jejunum greater than duodenum). Bile acids enhanced oxalic acid absorption in the large and small intestine and increased extracellular space; calcium, however, markedly decreased mucosal-serosal transport of oxalic acid. Cholestyramine known to reduce oxalate excretion in hyperuxaluria associated with ileal resection did not directly affect absorption of oxalic acid, but decreased the enhanced absorption of oxalic acid induced by bile acids. The results suggest that the beneficial therapeutic effect of cholestyramine in hyperuxaluria is rather mediated by its bile acid binding activity than by direct binding of oxalic acid.
回肠切除患者的肠道高草酸尿症和草酸钙尿路结石似乎是由肠道对草酸盐的过度吸收引起的。草酸盐过度吸收的机制尚不清楚。因此，采用体外技术在大鼠肠道中研究了草酸的肠道转运。草酸通过简单的被动扩散机制被吸收。吸收速率从结肠到十二指肠逐渐降低（结肠＞回肠＞空肠＞十二指肠）。胆汁酸增强了草酸在大肠和小肠的吸收，并增加了细胞外间隙；然而，钙显著降低了草酸的黏膜-浆膜转运。已知考来烯胺可减少回肠切除相关的高草酸尿症中的草酸盐排泄，它并不直接影响草酸的吸收，但降低了胆汁酸诱导的草酸吸收增强。结果表明，考来烯胺在高草酸尿症中的有益治疗作用更多地是由其胆汁酸结合活性介导的，而不是由草酸的直接结合介导的。
