Intestinal Enzyme Activities Following Whole-Body Irradiation in Hamsters 1

Abstract

Summary

The phosphomonoesterase and Mg- (Na + K) -adenosine triphosphatase (ATPase) activities were measured in the mucosa of the small intestine of hamsters (Mesocrkelus auratus) exposed to 1,000 rads ⁶⁰Co whole-body irradiation. The enzyme assays were made in irradiated and sham-irradiated hamsters sacrificed at intervals through Day 4 postirradiation. The two enzy-mic activities expressed per unit of tissue weight were significantly higher in the irradiated animals as compared to the sham-irradiated group at Day 2 postirradiation. No changes were found in the protein contents of jejunal mucosa between irradiated and sham-irracliated animals. While the ATPase activity was significantly lowered at Day 4, the phosphomonoesterase activity was observed to be higher at that time. The increase in enzyme activities may represent increased synthesis of these enzymes in the crypt cells that gave origin to the mature cells of the intestinal villi of animals sacrificed at Day 2 postirradiation. The increase in ATPase activity at Day 2 followed by a decrease at Day 4 corresponds to the previously observed alterations in the intestinal glucose absorption by irradiated hamsters.