title: [Potentially pre-neoplasics areas in rat's liver associated to chronic use of phenobarbital].
abstract: BACKGROUND
  Phenobarbital has been used in experimental models because it is an important agent of carcinogenesis promotion in the liver of rats, and it is also non-genotoxic, organ-specific and dose-dependent.
  
  
  OBJECTIVE
  To evaluate the effects of the daily administration of phenobarbital in old rats treated with phenobarbital since their birth up to 24 months of age, in the absence of concomitant administration of chemical agents, which initiate carcinogenesis.
  
  
  METHODS
  A control group of male Wistar rats was fed with a basic diet and a second group was fed with the same basic diet added of 0.05% of phenobarbital, for a period of 24 months. Medium and right liver fragments were submitted to the histological processing and they were stained by hematoxiciline and eosin and were immunohystochemically colored to glutathione S-transferase placentary form.
  
  
  RESULTS
  Glutathione S-transferase placentary positive zones were detected in both groups and the images were analyzed concerning their number and surface extension through the technique of histometry analyses.
  
  
  CONCLUSIONS
  Chronic use of phenobarbital did not modify the number of glutathione S-transferase placentary form positive areas. Although, data indicates that glutathione S-transferase placentary form positive areas media size are increased, probably because there are an increase in their evolution capacity and irreversibility.
authors.affiliation: Fundação Faculdade Federal de Ciências Médicas de Porto Alegre, RS. hubertsilva@brturbo.com
authors.forename: Helena Terezinha Hubert
authors.initials: HT
authors.lastname: Silva
authors.forename: Antonio Atalíbio
authors.initials: AA
authors.lastname: Hartmann
mesh_terms: D000818:Animals; D002273:Carcinogens / Q000008:administration & dosage / Q000494:pharmacology*; D005982:Glutathione Transferase / Q000378:metabolism*; D007150:Immunohistochemistry; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced / Q000201:enzymology* / Q000473:pathology; D008297:Male; D010634:Phenobarbital / Q000008:administration & dosage / Q000494:pharmacology*; D011230:Precancerous Conditions / Q000201:enzymology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002273:Carcinogens; D005982:Glutathione Transferase; D010634:Phenobarbital