title: Influence of level of dietary protein on tryptophan-induced promotional activity in induction of gamma-glutamyl transpeptidase-positive foci of rat liver.
abstract: The influence of varying the dietary protein content on the emergence of gamma-glutamyl transpeptidase (GGT)-positive foci in the livers of male rats fed elevated (2%) L-tryptophan (TRP) after being exposed to a hepatocarcinogen was investigated. Subtotal hepatectomies were performed, and 18 hr later the rats were treated with diethylnitrosamine (30 mg/kg). Ten days later four dietary groups were followed for 10 weeks: (1) control diet containing 21% protein (C); (2) control diet containing 5.3% protein (C-LP); (3) C + TRP; and (4) C-LP + TRP. Rats fed the C-LP diet developed heavier livers but fewer and smaller GGT + foci than did rats fed the C diet. Rats fed elevated TRP diets (C + TRP and C-LP + TRP) developed more and larger GGT + foci than did rats fed the regular control diets (C and C-LP), indicating that the promotional effect of elevated dietary TRP was similar at the two levels of dietary protein.
mesh_terms: D000818:Animals; D001835:Body Weight; D004044:Dietary Proteins / Q000494:pharmacology*; D004052:Diethylnitrosamine; D006498:Hepatectomy; D008099:Liver / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D008297:Male; D011230:Precancerous Conditions / Q000139:chemically induced / Q000201:enzymology* / Q000473:pathology; D014176:Protein Biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D014364:Tryptophan / Q000494:pharmacology*; D005723:gamma-Glutamyltransferase / Q000096:biosynthesis*
chemical_list: D004044:Dietary Proteins; D004052:Diethylnitrosamine; D014364:Tryptophan; D005723:gamma-Glutamyltransferase