title: Comparison of liver tumor frequencies after intermittent oral administration of different doses of N-nitrosopyrrolidine in Sprague-Dawley rats.
abstract: N-Nitrosopyrrolidine (N-Pyr) was administered orally to 400 Sprague-Dawley rats. An additional group of 80 rats served as an untreated control. There were 5 individual groups in which the effects of different periods of dosing and varying intervals without treatment were compared. Individual doses corresponded to 0.0, 1.0, 1.2 and 2.0 mg/kg per day. The total dose (600 days after the start of the trial) always amounted to 600 mg/kg N-Pyr. Significantly different incidences of liver tumors were observed in the individual N-Pyr-treated groups. The findings support the assumption that tumor risks not only depend on individual and total doses of the administered carcinogen, but are also an age-related function.
mesh_terms: D000284:Administration, Oral; D000367:Age Factors; D000818:Animals; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced*; D008297:Male; D009242:N-Nitrosopyrrolidine / Q000633:toxicity*; D009602:Nitrosamines / Q000633:toxicity*; D051381:Rats; D011919:Rats, Inbred Strains; D012306:Risk
chemical_list: D009602:Nitrosamines; D009242:N-Nitrosopyrrolidine