Enzyme activities in ageing small intestine and modifications after irradiation.

Brush border enzyme activities in control rats of different ages were studied. Disaccharases, dipeptidases and alkaline phosphatase levels were similar in both age groups. When the rats were sacrificed at two different times of the day the activity was significantly lower in the morning than in the evening in both adult and young animals. No similar differences were observed in lysosomal activities. After irradiation the enzyme activities in both groups presented the same patterns although variations were more marked in adult animals. At 120 hrs the tendency to return to control levels appeared less evident in adult rats. Morphologic data confirmed these results.