RESPONSE OF INTESTINAL TRANSGLUTAMINASE ACTIVITY TO DIETARY PHYTOHEMAGGLUTININ

The behaviour of the activity of tissue transglutaminase. a calcium-de pendent enzyme, and the levels or polyamines, which are physiological substrates for the enzyme, were studied in rat small intestine induced to grow by lectin phytohaemagglutinin. Transglutamine activity greatl y increased in the homogenates and the cytosolic fractions of the inte stinal mucosa of lectin-treated rats compared to that of untreated ani mals, The measurement of enzyme activity in the presence of monodansyl cadaverine, a competitive inhibitor of transglutaminase, testified tha t the assayed enzyme activity was authentic transglutaminase. As regar ds polyamines, the level of spermine did not change,whereas putrescine and spermidine contents were enhanced. The activation of transglutami nase, which was probably dm to Ca2+ accumulation in enterocytes, could have a role in maintaining enterocyte adhesion and intestinal cell ho meostasis, and/or repairing lectin-induced damages of microvilli of th e gut epithelium.