Abstract

Rectal biopsy specimens from control subjects, patients with either active or quiescent ulcerative colitis, and patients with Crohn's colitis were examined histologically and assayed for marker enzymes associated with tissue organelles. They were catalase (peroxisome); neutral alpha-glucosidase (endoplasmic reticulum); alkaline phosphatase (plasma membrane); malate dehydrogenase (mitochondria); lactate dehydrogenase (cytosol). There was no significant change in these enzyme activities in patient samples compared with controls. Activities of three acid hydrolases (lysosomal enzymes), beta-glucuronidase, acid phosphatase, and N-acetyl-beta-glucosaminidase, were also assayed in the biopsy samples. Decreased activities of all three enzymes were noted in ulcerative colitis, particularly in active disease. Normal values were obtained in Crohn's colitis. Measurement of lysosomal integrity by assays of latent N-acetyl-beta-glucosaminidase activity revealed similar results in control and colitic subjects. It is suggested that the lysosomal changes reflect a specific tissue release of enzyme and may be implicated in the pathogenesis of the tissue damage.