BOSTON (AP) -- Massachusetts Senate President Therese Murray says she will not seek re-election to the chamber when her term expires at the end of the year.

Murray is barred by term limits from serving as president beyond March 2015. She was elected senator of the Plymouth and Barnstable District in 1992 and became the first woman to head the chamber in March 2007.

The Democrat said in a statement released Saturday that she is humbled to represent her constituency and to lead the senate.

Murray did not disclose her plans for the future, saying only that she looks forward to working on issues that she is most passionate about "for many years to come."

State Sen. Stanley Rosenberg, an Amherst Democrat, is set to succeed Murray after securing the backing of enough fellow senators.