Apolipoprotein A-I stimulates placental lactogen expression by human trophoblast cells.

Earlier studies from our laboratory indicated that apolipoprotein A-I (Apo A-I) stimulates the acute release of human placental lactogen (hPL) from trophoblast cells in culture. We have now demonstrated that Apo A-I also causes a secondary increase in hPL release, beginning about 6 h after exposure to Apo A-I, that is blocked by cycloheximide and actinomycin D. Apo A-I also stimulated a dose-dependent increase in hPL promoter activity in JAR cells transfected with a 1.