Cloning of human hepatic stimulator substance requires clarification of whether the substance is the product of gene expression of liver cells. In this article the translation experiment in Xenopus Zaeuis oocytes indicates that poly (A) + messenger RNA of human fetal liver cells could conduct the biosynthesis of human hepatic stimulator substance. The translated human hepatic stimulator substance is a heat-, acid-and alkaline-resistant, but specific hepatic-stimulating, protein with a molecular weight in the range of 10 to 30 k D and with secreting ability. The characteristics of the translated human hepatic stimulator substance are consistent with those of biochemically purified human hepatic stimulator substance from human fetal liver cells. These results demonstrate that human hepatic stimulator substance is a product of gene expression of human fetal liver cells and that the complementary DNA of human hepatic stimulator substance could be screened from the complementary DNA library of human fetal liver tissue. (HEPATOLOGY 1993;17:225-229.)
Acute fulminant liver failure (FLF) is a disease with poor prognosis and high mortality, and it issues a great challenge to medical therapy (1). Recent investigation suggests that human fetal liver cell transfusion could effectively improve (or even cure) clinical FLF and greatly reduce its mortality (2-4). Furthermore, the results of ours (5, 6) and others' (7) studies on the characteristics of human hepatic stimulator substance (HSS) and the results of studies on rat, mouse, dog, pig and rabbit HSSs (8-12) have implied that HSS in human fetal liver cells (FLC) might be responsible for the remarkable therapeutic consequence of human FLC in the treatment of FLF because of biological function in initiation or stimulation of hepatic regeneration. In meeting the needs of further clinical investigation and trials, the production of human hepatic stimulator substance on a large scale by genetic engineering becomes an important projects. For this purpose, we