Champion of Gay Rights to Leave New York State Senate

State Senator Thomas K. Duane, who first burst onto the political scene two decades ago, when he disclosed during a successful bid for City Council that he was H.I.V. positive, and later made his mark as the first openly gay member of the Senate, has decided not to seek re-election.

On Monday, Mr. Duane, a Democrat, will announce his decision to call it quits, opening up the seat in a district that stretches from the Upper West Side to Greenwich Village, and across to the East Village.