To investigate the direct effect of glucocorticoids on sialylation of intestinal brush-border hydrolases, explants of fetal and suckling rat intestine were maintained in serum-free or serum-containing organ culture with or without dexamethasone (Dx). Glucoamylase and dipeptidyl peptidase IV developed in organ culture from 18-day-old fetuses persisted in highly sialylated forms for 8 days irrespective of Dx presence, parallel in vivo development leading to less sialylated forms at the age of 6 days. In postnatal cultures the Dx-stimulated glucoamylase appeared in a new highly sialylated form never seen after the hormone application in vivo. These findings are in agreement with the elevation of bound sialyltransferase (ST) of cultured intestine in protein-free media. In serum-containing medium Dx stimulated the formation and release of soluble ST into the culture medium.

Institute of Physiology Czechoslovak Academy of Sciences Prague

Brush border enzyme activities in the small intestine after long-term gliadin feeding in animal models of human coeliac disease