Effect of leukemia and methotrexate on digestive enzymes in the jejunum of mice.

A leukemic mouse model was employed to elucidate the separate effect of leukemia and cytotoxic drugs on the jejunal mucosa and its associated digestive enzymes. The mitotic activity, depth of the crypt and villus-crypt quotient were not significantly changed in leukemic mice in comparison to normal mice. The mitotic activity and the depth of the crypt 48 h after 20 mg methotrexate (MTX)/kg were significantly reduced (p less than 0.01) in leukemic mice. Sucrase (p less than 0.001) and maltase (p less than 0.025) activities in the jejunum from leukemic mice were significantly elevated in comparison with non-leukemic controls. In both non-leukemic and leukemic mice, the dose-response curves for MTX administration revealed a significant decrease and a nadir in sucrase (p less than 0.001) and maltase (p less than 0.0025) activities at the dosage of 20 mg/kg. Thus, in the mouse model, leukemia per se does not contribute to significant diminution in small intestinal function. In the small intestine, MTX appears to be responsible for a decrease in the mitotic activity of crypt cells, depth of the crypt and diminished sucrase and maltase activities.