UV-B Induced stimulation of phosphatidylinositol 3-kinase in human fetal hepatocytes.

We investigated the effect of UV-B irradiation on PI 3-kinase activity in human fetal hepatocytes. When cells were exposed to monochromatic (304nm) UV-B light, a significant increase in intracellular PI 3-kinase activity was observed in a dose dependent manner with maximal activity upon 1500 Jm(-2) irradiation. At 1500 Jm(-2) dose PI 3-kinse activity increased by 80% in membrane fraction of fetal hepatocytes of 25 weeks gestation. PI 3-kinse inhibitors wortmannin and LY294002 specifically inhibited the UV-B induced lipid kinase activity and blocked significantly the UV-B induced cell viability. The data suggests a correlation between cell survival and elevated levels of PI 3-kinase and suggest that UV-B irradiation at a dose of 1500 Jm(-2) is ideal for fetal hepatocyte transplantation. Also, PI 3-kinase levels could be a representative marker for viable UV-B irradiated fetal hepatocytes for transplantation.