Alterations in enzymatic activities of the intestinal mucosa during the course of Giardia lamblia infection in mice.

Decline in the specific activities of intestinal cytosolic glucose-6-phosphate dehydrogenase (G6PD) and isocitrate dehydrogenase (ICDH); brush border glucoamylase, and isomaltase; and basolateral (Na+, K+)-ATPase activities were observed during the establishment, acute phase and decline phase of infection in Giardia lamblia-infected mice. The degree of decline in the activities of various enzymes correlated well with the number of trophozoites counted in the jejunum. There appeared to be a gradual recovery of enzymatic activities during the decline phase of infection, when the number of trophozoites also declined. The decline in activities of these enzymes may contribute to malabsorption of nutrients during giardiasis.