May be involved in hepatocellular function and development. Secreted into blood in a truncated form. Liver-specific. Expressed only in the hepatocytes. Expression begins as early as 6.5 dpc and very early in fetal liver (at least from 11.5 dpc). Expression level changes in different developmental stages. Levels decrease to a minimal level at 17.5 dpc and then increase gradually to the maximal level at about 7 days after birth.