title: The influence of estrogen on liver regeneration: an experimental study in rats.
abstract: OBJECTIVE
  To recognize the regenerative capacity influenced by the administration of estradiol.
  
  
  METHODS
  42 female Wistar rats were used, divided into two groups, the control and the experiment group. A resection of approximately 70% of the liver was made in the liver of these animals. The control group received an intramuscular injection of one ml of peanut oil. The experiment group were given estradiol hexahydrobenzoate (50 microg) diluted in one ml of peanut oil. Calibrations were done after 36 hours and 7 days, using three methods: the formula of Kwon et al.21, to recognize gain in volume, counting of the mitosis figures in five fields and the percentage of positive PCNA nuclei.
  
  
  RESULTS
  Gain in volume (mass) was similar in both groups after 36 hours (p=0.1873) and higher in the experiment groups after seven days (p=0.0447). Microscopy showed a similar number of mitosis figures after 36 hours (p=0.3528) and a tendency to be higher in the experiment group after 7 days (p=0.0883). The average of positive PCNA nuclei was higher in the experiment group both after 36 hours (p=0.0009) and 7 days (p=0.0000).
  
  
  CONCLUSIONS
  The estradiol hexahydrobenzoate improved liver regeneration in rats submitted to a 70% hepatectomy.
authors.affiliation: Surgical Techniques and Experimental Surgery Program, School of Medicine, Federal University of Paraná (UFPR), Brazil. biondo@avalon.sul.com.br
authors.forename: Maria de Lourdes Pessole
authors.initials: Mde L
authors.lastname: Biondo-Simões
authors.forename: Thomas Rolf
authors.initials: TR
authors.lastname: Erdmann
authors.forename: Sérgio Ossamu
authors.initials: SO
authors.lastname: Ioshii
authors.forename: Jorge Eduardo Fouto
authors.initials: JE
authors.lastname: Matias
authors.forename: Hugo Leonardo Guaita
authors.initials: HL
authors.lastname: Calixto
authors.forename: Diego José
authors.initials: DJ
authors.lastname: Schebelski
mesh_terms: D000818:Animals; D004247:DNA / Q000096:biosynthesis; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D006498:Hepatectomy; D008115:Liver Regeneration / Q000187:drug effects* / Q000276:immunology; D008938:Mitosis; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D004967:Estrogens; D018809:Proliferating Cell Nuclear Antigen; D004958:Estradiol; D004247:DNA; C529764:estradiol hexahydrobenzoate