Electrical resistance and ATPase levels in the cecal wall of germ free and conventional rats.

(a) Electrical resistance across the cecal wall of germfree rats is higher than in conventional controls when the luminal fluid is a physiological solution. Transmural resistance of the cecum increases both in germfree and conventional rats when the supernatant from cecal contents of germfree rats is used as luminal fluid. These phenomena might be due to an effect of germfree intestinal contents on the ionic composition and/or on the dimensions of intercellular pathways within the intestinal epithelium. (b) Total and Na+ and K+ stimulated ATPase show higher levels in mucosal scrapings from the ileum and cecum of germfree rats than in conventional controls. This characteristic of the germ-free lower bowel may be associated with the greater "absorptive efficiency" which it was found to display when relieved from luminal inhibitory substances.