Modifications in the Brush Border Enzymes of the Small Intestine after Irradiation at Different Times of the Day

The effects of irradiation at different times of the day on rat intestinal goblet cells

“…Previous similar quantitative studies undertaken in different parts of the small intestine (duodenum, proximal and distal jejunum and terminal ileum) support these results (Becciolini et al 1976). When higher doses, or fractionated doses are used, the changes are of the same general pattern but may be quantitatively more pronounced (Becciolini 1987, Becciolini et al 1976, 1982c, 1983d, 1984, 1985, 1986, 1987b, 1995. The changes described here were seen in all of the groups of animals irradiated at different times of the day, even if there were differences of the levels and duration of the changes: the maximum increase of goblet cell number and goblet cell…”

A low dose of ionizing radiation increases luminal release of intestinal peptidases in rats

“…It is known that brush border enzyme activities show circadian oscillation (Becciolini et al 1977(Becciolini et al , 1982(Becciolini et al , 1996(Becciolini et al , 1997Kaufmann et al 1978). To exclude the chronobiological in¯uences, in the present study the time at which irradiation and perfusion were performed was rigidly the same in each experiment.…”

“…The terminal digestion of oligomers is performed by disaccharases, dipeptidases, and other enzymes as a prerequisite for the intestinal absorption of monosaccharides and amino acids. These enzymes are localized on the outer layer of the plasma membrane of the small intestine columnar cells (Becciolini et al 1982). Early investigations of radiation-induced mucosal damage have focused on tracking the localization of enzymes involved in carbohydrate metabolism as an indicator of the type and extent of injury (Becciolini et al 1972(Becciolini et al , 1973(Becciolini et al , 1982(Becciolini et al , 1987Keelan et al 1989).…”

Protective effect of oral phosphatidylcholine on radiation-induced release of intestinal peptidases in rats

“…It is known that brush border enzyme activities show circadian oscillation (Becciolini et al 1982(Becciolini et al , 1996(Becciolini et al , 1997. To exclude any chronobiological in¯uences, in the present study the time at which feeding, irradiation, and perfusion were performed was rigidly the same in each experiment.…”

“…Proteins which exhibit important membrane function, such as enzymes, receptors, and transporters, are enclosed in the lipid bilayer (Hagve 1988). Impairments of the membranes, e.g., induced by radiation, drugs or diet, considerably alter enzyme activities in the bowel by altering membrane composition (Becciolini et al 1974(Becciolini et al , 1982(Becciolini et al , 1987a(Becciolini et al , 1987bKeelan et al 1989). This variation is associated with changes in membrane function (Gupta et al 1993;Spector and Yorek 1985;Clandinin et al 1985).…”