Glutathione peroxidase and glutathione S-transferase, class alpha, in rat intestine. Immunohistochemical and immunoblotting studies on changes in expression of these antilipoperoxidative enzymes during normal development.

Glutathione peroxidase (GSH-PO) and glutathione S-transferase (GST), class alpha, showing GSH-PO-like enzymatic activity, were localized immunohistochemically in frozen sections of rat intestine in order to elucidate changes in the expression of these antilipoperoxidative enzymes during normal development. The direct immunoperoxidase method was performed using specific rabbit antibodies (Fab fragments) against the enzymes purified from rat liver. Immunoreactive GSH-PO and GST-alpha were demonstrated in the intestinal villous epithelial cells. In the duodenum, GSH-PO was positive during the period from 19 days of gestation to 1 week after birth, while GST-alpha was negative during this period. Two weeks after birth, positivity for GST-alpha appeared, and GSH-PO became undetectable. In the ileum, both of the enzymes were observed until 2 weeks of age, but after weaning their expression disappeared. These immunohistochemical findings were confirmed by immunoblot analysis using intestinal tissue extracts. To evaluate environmental effects on the expression of these enzymes, germ-free animals, common bile duct-ligated rats, and Hank's solution-fed infant rats were prepared. No remarkable alterations in the immunohistochemical localization pattern were observed. Since the switching of enzyme expression around the time of weaning was not influenced by these experimentally induced environmental conditions, it appears that these enzymatic changes are genetically predetermined.