REGROWTH OF THE RAT BILIARY TREE AFTER 70-PERCENT PARTIAL-HEPATECTOMYIS COUPLED TO INCREASED SECRETIN-INDUCED DUCTAL SECRETION

Background & Aims: After partial hepatectomy, liver regeneration occur s with the return of hepatocyte mass to normal, Limited data exist reg arding the renewal of the biliary tree after partial hepatectomy, This study tested the hypothesis that, after partial hepatectomy, the bili ary tree regenerates by proliferation of the remaining cholangiocytes, leading to an increase in secretin-induced ductal bile secretion, Met hods: After 70% partial hepatectomy, cholangiocyte proliferation was a ssessed in situ by morphometric analysis and in vitro by measurement o f H-3-thymidine incorporation. Ductal secretion was estimated by measu rement of secretin receptor gene expression and adenosine 3',5'-cyclic monophosphate (cAMP) levels in vitro and by the effect of secretin on ductal bile secretion in vivo, Results: DNA synthesis was undetectabl e in control cholangiocytes, increased and peaked at day 3 after parti al hepatectomy, and returned to normal by day 28, Morphometric analysi s showed regrowth of the biliary tree beginning at day 1 with restorat ion by day 10. The expression of secretin receptor gene and secretin-i nduced cAMP levels and secretin-induced bicarbonate-rich choleresis in creased during the period of bile duct renewal. Conclusions: After par tial hepatectomy, the increase in secretin-induced ductal bile secreti on observed during bile duct renewal results from proliferation of rem aining cholangiocytes.