NASHVILLE — New state reports show Tennessee’s 12th District Senate race has become a financial battleground, with organized labor and trial lawyers fighting doctors and business interests.

Between July 29 and Sept. 30, Tennessee trial lawyers poured $15,000 through their political action committee into Democrat Becky Ruppe’s primary and general election campaigns, according to records filed this week with the Tennessee Registry of Election Finance.

Physicians, meanwhile, who are often at odds with trial lawyers in the legislature, gave $2,000 through their PAC to Republican Ken Yager. Records show $1,000 came from the Tennessee Group Practice Coalition PAC and $500 from the Tennessee Hospital Association. Some health care professionals also gave money, records show.

The third-quarter reports show that Mr. Yager collected some $67,000 in the latest period and had $177,000 in cash on hand. Ms. Ruppe raised nearly $76,000 and had $114,500 on hand.

Ms. Ruppe, the Morgan County executive, and Mr. Yager, a former Roane County executive, are battling for the seat vacated by Tommy Kilby, D-Wartburg.

Control of the state Senate may hang in the balance. The Senate is split 16-16, plus one independent who sides with Democrats on many issues. But the senate Speaker, who has the title lieutenant governor, is a Republican. The GOP dominates important committees such as the Commerce, Labor and Agriculture Committee and the Judiciary Committee.

Records show labor union PACs gave Ms. Ruppe $38,500. Among the top donors were the Tennessee AFL-CIO Labor Committee and the Plumbers & Pipefitters Education Committee in Nashville, which each gave $7,000. The Tennessee Laborers PAC gave the Ruppe campaign $7,500.

Mr. Yager collected $1,500 from the Tennessee Chamber of Commerce & Industry. AT&T Tennessee PAC gave him $2,500. Chattanooga developer John Thornton gave $750 while Ruby Tuesday CEO Sandy Beall kicked in $250. Several dozen businessmen and business PACs collectively gave nearly $19,000 to Mr. Yager.

Tennessee Chamber of Commerce & Industry President Deborah Woolley said one of the “overriding issues” in that race and some others is which party will claim the speakership and run the Senate.

“For us, one of the key things is a vote for (Speaker) Ron Ramsey will be facilitated by, I believe, if Ken Yager is elected,” Ms. Woolley said.

Tennessee AFL-CIO Labor Council Secretary Eddie Bryan said the present Commerce Committee has six Republicans and three Democrats.

“You can’t get a piece of legislation out. You can’t get one of those Republicans to talk to you as far as working folks are concerned,” he said.

He said labor unions didn’t always like how the panel operated under former Democratic Speaker John Wilder. But he said the committee was fair until Sen. Ramsey ousted Mr. Wilder as speaker in 2007.

“We don’t want to control anything,” Mr. Bryan said. “We just want a fair shake and under Ron Ramsey we haven’t got nothing.”

Both Ms. Woolley and Mr. Bryan agreed that key disagreements between business and labor involve issues such as a “living wage,” or state minimum wage, and workers compensation.

Senate District 12 includes Campbell, Fentress, Morgan, Rhea, Roane and Scott counties.