Abstract
Regional differences of an NAD(P)H-dependent H2O2-generating enzyme activity in the rat small intestinal mucosa were electron-cytochemically investigated. The H2O2-generating activity was localized on the apical membrane covering microvilli of intestinal absorptive cells in the duodeno-jejunum. The activity was weak in absorptive cells at the mitotic area of villus, becoming higher toward its apex. The spherical membrane covering absorptive cells which are in the process of being extruded at the apical extrusion zone exhibited the activity. Activity was also noted in the apical cell membrane of goblet cells, although the activity was weaker than that in the absorptive cells.
The ileal activity was apparently weaker than that of the duodeno-jejunum. These results seem to indicate that there are local variations in the NAD(P)H-depending H2O2-generating activity among intestinal epithelial cells.
