Alterations in the expression of intestinal enzymes in rats exposed to nickel.

The effect of feeding nickel (50 mg kg(-1) body weight) daily for 7 days was studied on the development of various brush border enzymes across the crypt-villus axis. The activities of brush border maltase (P < 0.05), lactase (P < 0.05), alkaline phosphatase (P < 0.05) and leucine amino peptidase (P < 0.05) were augmented in purified brush borders, whereas sucrase, trehlase (P < 0.01) and glutamyl transpeptidase (P < 0.05) were reduced in nickel fed animals compared with controls. Kinetic and heat inactivation studies with brush border sucrase and alkaline phosphatase confirmed these findings. Western blot analysis of alkaline phosphatase showed a strong signal for the enzyme protein but a reduced level of sucrase antigen in nickel fed rat intestine compared with the controls. These findings suggest that the expression of various brush border enzymes along the crypt-villus axis is modulated in rat intestine exposed to nickel, which may disrupt the digestive functions of the intestinal tissue.