Plasma levels of HGF in rats treated with tumor promoters.

Hepatocyte growth factor (HGF), mol. wt 105,000 is a potent mitogen for hepatocytes. HGF is strongly associated with compensatory regeneration in the liver after two-thirds partial hepatectomy and carbon tetrachloride administration. Plasma levels of HGF increase markedly during early stages of compensatory hyperplasia caused by these treatments. This is followed by an increase in HGF mRNA in the liver. This is in contrast to other growth factors for liver (epidermal growth factor, transforming growth factor alpha and acidic fibroblast growth factor) whose levels in plasma remain virtually undetectable during compensatory hyperplasia. We have shown that during augmentative hyperplasia caused by the tumor promoters alpha-hexachlorocyclohexane, phenobarbital and ciprofibrate, plasma levels of HGF also increase. This increase of HGF occurs during the transient wave of DNA synthesis caused by administration of these xenobiotics, providing further support for HGF as being the stimulator of DNA synthesis during both augmentative and compensatory hyperplasia.