OXIDATIVE METABOLISM OF WASHED RESIDUES OF RAT SMALL INTESTINAL EPITHELIUMf

Few studies have been made of the energy-producing oxidation reactions catalyzed by small intestinal epithelium. Studies made with slices have shown that this tissue exhibits a high level of oxidative activity and a high rate of aerobic glycolysis (Dickens and Weil-Malherbe, 1941). Homogenates of the epithelium catalyze the oxidation of a-ketoglutarate (Moinuddin and Cushing, 1957). Isocitric dehydrogenase (Adler et al., 1939) and aconitase (Johnson, 1939) are present in intestinal extracts, and respiration of intestine was stimulated markedly by glucose and slightly by glutamic acid (Rose and Archdeacon, 1953), but the distribution of these activities in various layers of the gut was not described. Intestinal xanthine oxidase is thought to be localized in the mucosa (Westerfeld and Richert, 1954). The accumulation of citrate in the small intestine after the injection of fluoroacetate into animals indicated that the citric acid cycle probably is a major oxidative pathway in the small gut as in other animal organs (Buffa and Peters, 1949) but to what extent this is true for the different gut layers was not determined. Thus, there appears to be little known regarding specific oxida