A semipurified diet that suppresses phenobarbital promotion of hepatocarcinogenesis in the rat.
Six groups of F344/N female rats were fed either a modified AIN-76 diet (20% casein, 5% corn oil, 65% cornstarch, 5% cellulose) (AIN) or a diet formulated by Dr. M. Pariza (PD) (30% casein, 10% partially hydrogenated corn oil, 40% sucrose, 15% cornstarch) beginning four days before 70% partial hepatectomy. One day after the surgery, one group fed each diet was intubated with 10 mg/kg diethylnitrosamine (DEN). One week later, these groups plus one control group fed each diet were given 0.05% phenobarbital in the diet for 6 or 14 months. After the rats were killed, blocks of liver tissue were frozen on dry ice and stored at -70 degrees C. Three frozen serial sections were stained for gamma-glutamyltransferase, ATPase, and glucose-6-phosphatase. Numbers and volume of altered hepatic foci (AHF) were analyzed by stereological techniques. After 14 months of feeding these regimens, rats initiated with DEN and fed the AIN + PB had significantly greater numbers and a higher percent volume of the liver of most phenotypes of AHF than all other groups, including those fed PD + PB following initiation with DEN. The numbers of AHF exhibiting more complex phenotypes (i.e., scored by more than one marker) remained unaltered between 6 and 14 months. These findings indicate that the effectiveness of PB as a promoting agent in multistage hepatocarcinogenesis is significantly altered when fed with two different diets of known composition. Therefore, dietary composition can be a significant factor in studies of the stage of promotion in hepatocarcinogenesis.
Hendrich
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S
Food and Nutrition Department, Iowa State University, Ames 50011.
Glauert
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HP
Pitot
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HC
D000818:Animals; D001835:Body Weight; D003043:Cocarcinogenesis; D004032:Diet; D004052:Diethylnitrosamine; D005260:Female; D005526:Food, Formulated; D008099:Liver / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced* / Q000473:pathology; D009929:Organ Size; D010634:Phenobarbital / Q000037:antagonists & inhibitors*; D051381:Rats; D011919:Rats, Inbred Strains
D004052:Diethylnitrosamine; D010634:Phenobarbital