Fusarium proliferatum-fermented corn stimulates development of placental glutathione S-transferase-positive altered hepatic foci in female rats.

Groups of 8 6-w-old female Sprague-Dawley rats were initiated with 30 mg diethylnitrosamine (DEN)/kg. Control and initiated groups were fed a semipurified diet or diets supplemented with Fusarium proliferatum-contaminated corn to contain 20 or 50 mg fumonisin B1 (FB1)/kg. Histochemical staining for gamma-glutamyltransferase (GGT) and immunochemical staining for placental glutathione S-transferase (PGST), markers of altered hepatic foci (AHF), were performed on serial frozen hepatic sections. Gamma-glutamyltransferase -(+) AHF were not found in any group. Dosing with DEN significantly increased the number of PGST-(+) hepatocytes compared to the uninitiated groups. Groups fed F proliferatum-containing diets also had a significantly increased number of PGST-(+) AHF compared with those fed no F proliferatum. The volume percentage of liver occupied by PGST-(+) foci was significantly greater in the groups treated with DEN or F proliferatum. The number of PGST-(+) AHF/liver in the groups given DEN was also significantly greater than in the uninitiated groups. Fusarium proliferatum exposure also significantly increased the number of PGST-(+) AHF/liver. Feeding F proliferatum containing 20 mg FB1/kg promoted the development of DEN-initiated AHF in rats. Placental glutathione S-transferase was a more useful marker than GGT in detecting AHF produced by small amounts of F proliferatum mycotoxins fed after initiating dosing with DEN.