title: The role of polyamines in growth factor induced DNA synthesis in cultured rat hepatocytes.
abstract: OBJECTIVE
  Hepatocyte growth factor and transforming growth factor-alpha are growth factors with important roles in hepatocyte proliferation. The polyamines, putrescine, spermidine, and spermine are widely distributed in many different cells and play an essential role in cell growth and differentiation. The present study examined the role of polyamine in this growth promoting factor-induced hepatocyte proliferation, in primary cultured rat hepatocytes.
  
  
  METHODS
  Hepatocytes were isolated from rats by the collagenase perfusion method. Ornithine decarboxylase and S-adenosylmethionine decarboxylase activities were measured as the release of 14CO2 from L-[-14C]ornithine and S-adenosyl-L-[carboxyl14C]methionine, respectively. The concentration of polyamine was analyzed by high performance liquid chromatography.
  
  
  RESULTS
  When transforming growth factor-alpha and hepatocyte growth factor were added to the hepatocyte culture simultaneously, ornithine decarboxylase activity, S-adenosylmethionine decarboxylase activity, polyamine concentration and DNA synthesis increased additively. The increase in DNA synthesis caused by transforming growth factor-alpha, hepatocyte growth factor, or both was completely inhibited by alpha-difluoromethylornithine and methylglyoxal bis(guanylhydrazone). The inhibition was reversed by exogenous spermidine or spermine, but not by putrescine.
  
  
  CONCLUSIONS
  Increased spermidine or spermine levels are essential for hepatocyte proliferation in cultured rat hepatocytes.
authors.affiliation: Second Department of Biochemistry, Osaka City University Medical School, Osaka, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Higaki
authors.forename: I
authors.initials: I
authors.lastname: Matsui-Yuasa
authors.forename: K
authors.initials: K
authors.lastname: Hirohashi
authors.forename: H
authors.initials: H
authors.lastname: Kinoshita
authors.forename: S
authors.initials: S
authors.lastname: Otani
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology*; D002478:Cells, Cultured; D004261:DNA Replication / Q000502:physiology*; D017228:Hepatocyte Growth Factor / Q000502:physiology*; D008099:Liver / Q000166:cytology*; D008297:Male; D011073:Polyamines / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D016211:Transforming Growth Factor alpha / Q000502:physiology*
chemical_list: D011073:Polyamines; D016211:Transforming Growth Factor alpha; D017228:Hepatocyte Growth Factor