Demonstration of "hetero-beta-galactosidase" "in situ".

A method for the histochemical demonstration of "hetero-beta-galactosidase" was elaborated. The enzyme is demonstrated in cryostat sections by the semipermeable membrane technique. Pairs of membranes--one pre-washed in saline--are used. The most sensitive method is post-coupling demonstration with 6-Br-2-naphthyl-beta-D-glucoside. The incubation time must be short, to avoid diffusion. The method allows cellular localization. The method with alpha-naphthyl-beta-D-glucoside and hexazonium-p-rosaniline is less sensitive, but localization is better. Indigogenic methods are the least sensitive. The enzyme is localized in the supranuclear zone of differentiated enterocytes of the human, monkey and rabbit small intestine, with maximum activity in the jejunum. The activity of the enzyme is low in patients with coeliac sprue, in the active phase of the disease. In isolated lactase deficiency it is normal. In the kidney, the enzyme is localized chiefly in the cytoplasm of the proximal tubule cells.