The changes in circulating hepatocyte growth factor after partial hepatectomy in the baboon

There is no established model of regenerative liver resection in the baboon , and no study comparing the circulating hepatocyte growth factor (HGF) res ponse with the DNA synthetic response after liver resection. A mean 20% par tial hepatectomy (PH) was performed in 19 baboons and a sham operation comp rising liver mobilisation only was performed in 20 baboons. Blood HGF level s were measured up to 5 days after either procedure, using the human HGF en zyme-linked immunosorbent assay (ELISA) kit (Otsuka, Japan). The white cell count (WCC), aspartate transaminase (AST) and bilirubin were also measured . Liver regeneration, reflected by an increase in DNA synthesis, was determ ined from serial liver biopsies in 23 baboons, using a tritiated thymidine assay of liver thymidine kinase (TK). Liver resection and WCC had a signifi cant influence on circulating HGF levels. There was a linear relationship b etween WCC and circulating HGF levels, which was independent of PH. For a c onstant value of WCC, resection produced a peaking of HGF over time, with t he maximal levels occurring between 2 and 3 days, compared with the linear response in HGF in sham-operated baboons. Liver damage, as reflected by AST levels, was found to have no significant influence on circulating HGF leve ls. The 20% PH produced a significant increase in liver TK, with maximum le vels evident between 2 and 4 days. Accordingly in this baboon model of PH t he increase in biologically active, circulating HGF preceded the increase i n liver DNA synthesis over 5 days. This observation supports the role of HG F in hepatocyte proliferation and as an initiator of liver regeneration, an d suggests that further investigation into the potential endocrine action o f HGF could be studied in this established liver regenerative primate model .