The effect of hepatic stimulator substance (HSS) on liver regeneration arrest induced by 5-HT2 receptor blockade.

BACKGROUND The restorative effect of hepatic stimulator substance (HSS) against hepatic regeneration arrest induced by 5-HT2 receptor blockade was investigated. MATERIALS AND METHODS Male Wistar rats were subjected to 60-70% partial hepatectomy and to 5-HT2 receptor blockade at 16 h after partial hepatectomy by ketanserin administration (6 mg/kg bodyweight intraperitoneally; group I). HSS at the dose of 100 mg protein/kg bodyweight was administered at 10 or 17 h after partial hepatectomy in ketanserin-treated rats (groups II and III). The mitotic index in hematoxylin-eosin-stained liver sections, immunochemical detection of PCNA and Ki 67 nuclear antigens and the rate of [3H]-thymidine incorporation into hepatic DNA were used as indices of liver regeneration. RESULTS Liver regeneration, as evaluated by [3H]-thymidine incorporation into hepatic DNA, mitotic index, PCNA and Ki67 nuclear antigens, peaked at 40 h in groups I, II and III of rats and no significant differences were observed between the studied groups. CONCLUSION HSS administration is not capable of reversing the liver regeneration arrest induced by 5-HT2 receptor blockade.