title: P21waf-1/cip-1/sdi-1 is expressed at G1 phase in primary culture of hepatocytes from old rats, presumably preventing the cells from entering the S phase of the cell cycle.
abstract: To elucidate whether p21waf-1/cip-1/sdi-1 expression is associated with loss of growth potential of hepatocytes of old rats, we determined p21waf-1/cip-1/sdi-1 expression of hepatocytes from old (30 months) rats during the cell cycle in primary culture. A high level of expression of p21waf-1/cip-1/sdi-1 was detected at the G1 phase in old-rat hepatocytes, but after the S phase in young-rat hepatocytes. Consistently, the incidence of the cells positive for p21waf-1/cip-1/sdi-1 in nuclei before entering the S phase was significantly higher in old-rat hepatocytes than in young-rat hepatocytes. These results account for the loss of growth potential of old-rat hepatocytes in vitro and the marked retardation of regeneration of liver in old rats in vivo.
authors.affiliation: Department of Pathology, Sapporo Medical University School of Medicine, Japan. sawadan@sapmed.ac.jp
authors.forename: N
authors.initials: N
authors.lastname: Sawada
authors.forename: T
authors.initials: T
authors.lastname: Kojima
authors.forename: H
authors.initials: H
authors.lastname: Obata
authors.forename: M
authors.initials: M
authors.lastname: Saitoh
authors.forename: H
authors.initials: H
authors.lastname: Isomura
authors.forename: Y
authors.initials: Y
authors.lastname: Kokai
authors.forename: M
authors.initials: M
authors.lastname: Satoh
authors.forename: M
authors.initials: M
authors.lastname: Mori
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000235:genetics* / Q000378:metabolism; D016193:G1 Phase; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D016196:S Phase
chemical_list: C493958:Cdkn1a protein, rat; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins