MUCOSAL GLUCOSAMINE SYNTHETASE-ACTIVITY IN INFLAMMATORY BOWEL-DISEASE

Abnormalities in colonic glycoprotein synthesis have been implicated i n the pathogenesis of ulcerative colitis and Crohn's disease. Glucosam ine synthetase is the rate-limiting step in the biosynthesis of gastro intestinal glycoprotein and has been measured in control subjects (N = 23) and patients with ulcerative colitis (N = 26) or Crohn's disease of the colon (N = 20) classified according to the macroscopic status o f the rectum. Glucosamine synthetase activity was relatively constant around the normal colon but lower levels were found in the terminal il eum. In ulcerative colitis, glucosamine synthetase activity was simila r to controls (24.0 +/- 1.9) mmol/g wet (wt/hr) irrespective of diseas e activity (quiescent: N = 13, = 27.3 +/- 1.9; active N = 16, = 26.2 /- 2.3). Rectal glucosamine synthetase activity was normal in the pres ence of active Crohn's proctocolitis (29.4 +/- 3.1) but raised in pati ents with Crohn's colitis and rectal sparing (37.2 +/- 4.9 P < 0.02). Glucosamine synthetase activity was strongly influence by the degree o f epithelial preservation.