OKLAHOMA CITY (AP) - The number of Democratic lawmakers in the Oklahoma Legislature continues to dwindle, and Republicans are hopeful they can extend their majorities in the House and Senate in the fall.

Longtime Democratic Sen. Richard Lerblance of Hartshorne announced over the weekend that he would not run for his Senate seat again in the fall. He is the fourth Senate Democrat to announce plans to retire, which equals one-quarter of the Senate Democratic caucus.

Last year's Senate Democratic leader Sen. Andrew Rice resigned his seat and moved to Tennessee, and Sens. Charlie Laster of Shawnee and Judy Eason-McIntyre of Tulsa both say they won't run again in November.

Oklahoma Republican Party Chairman Matt Pinnell said Tuesday he's "very optimistic" Republicans can capitalize on the open seats.