THE IN-VITRO EFFECT OF AMMONIA ON DNA-SYNTHESIS IN RAT ENTEROCYTES

Objectives: Previous reports have suggested that ammonia influences th e total amount of DNA and DNA synthesis in the intestinal mucosa. Thes e findings may be of clinical importance because Helicobacter pylori i nfection in humans is associated with the increased local production o f ammonia and with chronic gastritis and peptic ulcers. We aimed to ex amine whether ammonia influences DNA synthesis in the small intestine in vitro. Methods: A small intestinal cell line (IEC-6 cells) from ger m-free rats was allowed to grow for 24 h in a nutrient-enriched medium . The cells were then incubated for 24 h with 1, 10 and 20 mmol/l ammo nium chloride, and with similar concentrations of ammonium carbamate, ammonium nitrate, ammonium acetate and urea. The cells were labelled w ith H-3-methyl-thymidine for 4 h and processed for autoradiography. DN A synthesis was evaluated by the labelling index (LI%) in a light micr oscope. Results: The median LI in controls was 21.3% (interquartile ra nge, 3.7-35.1), which was not significantly different from the values observed after administration of the various ammonia compounds and ure a. Conclusions: Physiological concentrations of ammonia do not influen ce cell proliferation in rat enterocytes in vitro.