title: Altered acinar distribution of glutamine synthetase and different growth response of cultured enzyme-positive and -negative hepatocytes after partial hepatectomy.
abstract: Partial hepatectomy (PH) results in the persistent drop of the specific activity of glutamine synthetase (GS) (EC 6.3.1.2). This drop correlates with the reduced proportion of GS+ hepatocytes and with the reduced GS+ area surrounding the central veins such that GS+ hepatocytes are arranged in a single cell layer only. Cultivation of hepatocytes isolated at various times after PH revealed considerable differences in the growth characteristics of GS+ and GS- hepatocytes discriminated by immunocytochemistry. In the absence or presence of epidermal growth factor and insulin, the labeling index of GS- hepatocytes peaked in cultures established 48 h after PH at 10% and 50%, respectively, while that of GS+ cells was much lower (2% and 6%). In cultures established at later times after PH the labeling index of GS- cells decreased gradually, while that of GS+ hepatocytes increased continuously, reaching about 20% and more than 50% for controls and epidermal growth factor/insulin-treated cultures, respectively, in cultures established 72 after PH. Norepinephrine stimulated the labeling index of both cell populations during the first 24 h only, but again GS- hepatocytes responded somewhat earlier than did GS+ hepatocytes. These results demonstrate that the differences in the growth characteristics of GS+ and GS- hepatocytes are due to different priming of these cells in vivo and may result in the different expansion of the respective cell populations during regeneration after PH.
authors.affiliation: Physiologisch-chemisches Institut, Universität Tübingen, Federal Republic of Germany.
authors.forename: R
authors.initials: R
authors.lastname: Gebhardt
mesh_terms: D000818:Animals; D001345:Autoradiography; D002478:Cells, Cultured; D004261:DNA Replication; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism*; D006498:Hepatectomy; D007124:Immunoenzyme Techniques; D008099:Liver / Q000166:cytology* / Q000201:enzymology; D008115:Liver Regeneration; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013936:Thymidine / Q000378:metabolism; D014316:Tritium
chemical_list: D014316:Tritium; D005974:Glutamate-Ammonia Ligase; D013936:Thymidine