Playboy Enterprises says Christie Hefner, the daughter of founder Hugh Hefner, is stepping down as chairman and chief executive.Playboy Enterprises Inc. has named Director Jerome Kern to serve as interim non-executive chairman while it looks for a replacement. Hefner joined Playboy in 1975 and was named chairman and CEO in 1988. She will stay on as CEO until Jan. 31, 2009, and remain on the board until a new CEO joins the company. In a statement, Hefner said the leadership change was her decision, but it follows signs of trouble for the Chicago-based publishing and entertainment company. In October, Playboy said it planned to cut 55 employees and eliminate 25 vacant positions due to the troubled economy.