Background/aims: Although follistatin is known to be a positive regulator in liver regeneration after hepatectomy, the effects of follistatin on regeneration following portal occlusion and on tumor growth are not known.
Methodology: In experiment 1, rats were injected with follistatin immediately following 70% hepatic resection (HR), ligation of the left portal vein (PVL), or ligation of the left hepatic artery (HAL). Hepatic regenerative activity then was determined. In experiment 2, rats were injected intraportally with AH130 tumor cells. At 7 days after injection, the same procedures were carried out as in experiment 1. In a third experiment, in vitro, AH130 cells were cultured with various concentrations of activin A or follistatin, and cell proliferation was assessed.
Results: In experiment 1, follistatin did not accelerate liver regeneration after PVL. In experiment 2, follistatin significantly increased liver weight after HR, but did not accelerate tumor growth in any group. In vitro, neither follistatin nor activin affected proliferation of tumor cells.
Conclusions: The mechanism of liver regeneration after PVL appears to differ from that after HR. Follistatin acts as a growth promoter for hepatocytes, but not for cancer cells.