EXPRESSION OF CALCIUM-BINDING PROTEIN REGUCALCIN MESSENGER-RNA IN THECLONED HUMAN HEPATOMA-CELLS (HEPG2) - STIMULATION BY INSULIN

The expression of hepatic Ca2+-binding protein repucalcin in the clone d human hepatoma cells (HepG2) was investigated, The change in regucal cin mRNA levels was analyzed by Northern blotting using rat liver regu calcin complementary DNA (0.9 kb of open reading frame). Regucalcin mR NA was expressed in HepG2 cells, although the mRNA was markedly expres sed in normal rat liver. Moreover, regucalcin protein in HepG2 cells w as detected by Western blot analysis using a polyclonal rabbit anti-re gucalcin antibody. Regucalcin mRNA expression in HepG2 cells was clear ly stimulated by the culture with insulin (10(-8) M) of the effective concentration. Regucalcin protein in HepG2 cells was also increased by the treatment of insulin (10(-8) M). The present results demonstrate that regucalcin is expressed in the transformed HepG2 cells, and that the expression is stimulated by insulin.