ARTICLES

Synthesis of macromolecules by intestinal cells incubated with ammonia

Mucosal cells isolated from the small intestine of chicks and rats were incubated with concentrations of ammonia normally found in the intestinal tract of mammals and birds. NH4Cl added to the incubation medium increased glucose metabolism in cells from both species. Ammonia stimulated incorporation of precursors into RNA and decarboxylation of orotic acid by cells isolated from chickens, but an increase in incorporation of precursors into DNA was not observed in cells from either species. Cultured embryonic chicken duodena showed increased incorporation of orotate into RNA with NH4Cl added to the medium. Rats immunized against jack bean urease showed lower urease activity per gram of dry intestinal content, lower intestinal weight, lower mucosal cell, and total gut protein and less protein per unit weight of DNA in the mucosal cell fraction. The results are compatible with the conclusion that ammonia PRODUCED IN THE INTESTINE BY BACTERIAL UREASES CAUSES SIGNIFICANT CHANGES IN THE CONTENT OF RNA and protein in intestine cells.