title: Effect of aging on proliferative activity of normal and carcinogen-altered hepatocytes in rat liver after a two-thirds partial hepatectomy.
abstract: Proliferative activity of normal and carcinogen-altered hepatocytic populations was investigated in Wistar rats of various ages ranging from 5 to 109 weeks old before and after a two-thirds hepatectomy. gamma-Glutamyltranspeptidase (GGT)-positive hepatocytic foci were induced by administration of a single dose of diethylnitrosamine. The incidence of nuclear labeling with [3H]thymidine was examined using simultaneous GGT histochemistry and radioautography. The [3H]thymidine index of hepatocytes in the GGT-positive foci was not greater than that of normal hepatocytes in both young and old non-hepatectomized rats. GGT-positive hepatocytes responded by proliferating after a two-thirds hepatectomy in all age groups. Although the response of normal hepatocytes to the growth stimulus markedly decreased in old rats, GGT-positive hepatocytic populations retained relatively high responses to the growth stimulus. These observations indicate that in old rats carcinogen-altered hepatocytes have a greater growth advantage than normal hepatocytes to exogenous and endogenous proliferative stimuli.
authors.forename: K
authors.initials: K
authors.lastname: Ogawa
authors.forename: H
authors.initials: H
authors.lastname: Mukai
authors.forename: M
authors.initials: M
authors.lastname: Mori
mesh_terms: D000375:Aging; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D004247:DNA / Q000096:biosynthesis; D004052:Diethylnitrosamine / Q000494:pharmacology*; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D008115:Liver Regeneration / Q000187:drug effects; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D005723:gamma-Glutamyltransferase / Q000378:metabolism
chemical_list: D004052:Diethylnitrosamine; D004247:DNA; D005723:gamma-Glutamyltransferase