Permeability of the rectosigmoid mucosa to tritiated water in normal subjects and in patients with mild idiopathic ulcerative colitis 1 RUVEN LEVITAN AND SIMCHA BRUDNO

It is well known that one severely disabling manifestation of ulcerative colitis is diarrhoea, and among the mechanisms suggested to account for it in this condition has been a derangement of absorption across the colonic mucosa. Previous studies utilizing other substances than water have failed to demonstrate deranged absorption from the inflamed rectosigmoid of patients with idiopathic ulcerative colitis (Levitan, Bikerman, Burrows, and Ingelfinger, 1963). The only quantitative information concerning absorption of water from the diseased colon in ulcerative colitis was obtained from studies on anaesthetized patients with advanced disease who were about to undergo colectomy (Duthie, Watts, de Dombal, and Goligher, 1964). In addition, these patients were treated with adrenal hormones. It was felt, therefore, that it would be of interest to obtain information about the transfer of water across the inflamed rectosigmoid mucosa in patients who had untreated mild ulcerative colitis in remission and were not under the influence of anaesthetics. The aim of the present study was to measure the permeability of the rectosigmoid mucosa to tritiated water in normal volunteers and in patients with untreated ulcerative colitis. The appearance of the tritiated water in venous blood following rectal instillation was used as a measure of colonic permeability. No attempt was made to measure net water absorption. This relatively simple technique was utilized in the hope that useful information could be obtained without physiological disturbance and without subjecting the patients to long, tedious intubation procedures.