At least six General Assembly incumbents were trailing opponents after early primary returns Tuesday evening — but many incumbents were turning back tough challenges.

With early results reported from polls across the state, state Sen. James Brochin, the northern Baltimore County Democrat known for an independent streak, led former Del. Connie DeJuliis, a more progressive candidate backed by Gov. Martin O'Malley.

"People like independence, and they like someone who will stand up to the establishment," said Brochin, who's voted against several of the governor's tax increases.

Baltimore Sen. Joan Carter Conway led City Councilman Bill Henry, who said he would be more responsive to constituents, and Baltimore Sen. Nathaniel McFadden was ahead of veteran political consultant Julius Henson, according to early results.

Conway, who declared victory, said she believed Henry's campaign was too negative and that turned voters off.

"People know that I do good work," Conway said. "I refused to stoop to his level in terms of negativity and misinformation. I think people respected that."

In another closely watched race, Montgomery County state Sen. Rich Madaleno, the state's first openly gay senator, appeared to be turning back a challenge from a transgender rights advocate.

Other incumbents faced tougher challenges. Baltimore City Dels. Keith Haynes, Keiffer J. Mitchell Jr. and Melvin L. Stukes were redistricted into a race for a single Southwest Baltimore seat. Haynes led after early voting results. If he prevails, that would leave Mitchell and Stukes — both General Assembly veterans — out of office.

In Frederick County, with nearly three-fourths of precincts reporting, Republican Senate leader David R. Brinkley lost to an aggressive challenge from the tea party wing of the GOP. Del. Michael J. Hough contended Brinkley didn't hew to conservative ideals coveted in the General Assembly's 4th District.

Hough said many members of the GOP are fed up with the policies of Democrat O'Malley, who is term-limited.

"It's a large shot at the establishment in Annapolis," he said. "The Republicans in western Maryland are sick of the taxing and spending. My voters feel completely disenfranchised."

On the Eastern Shore, incumbent Sen. Richard F. Colburn was behind Del. Addie Eckardt after early results.

Anne Arundel Del. Don Dwyer, whose campaign was hampered by a conviction related to a drunken boating accident, trailed four candidates in a six-challenger primary.

Despite an ethics censure by the General Assembly, Prince George's County Sen. Ulysses Currie led Del. Melony Griffith, who had pledged not to run a negative campaign against him.

With more than 540 candidates running for 141 seats in the House of Delegates and 47 seats in the state Senate, Tuesday's primaries set up a number of November showdowns between Democrats and Republicans.

But for some in heavily Democratic districts like Baltimore City or heavily Republican districts like Frederick County, the primary election has traditionally decided who will win office.

In Baltimore City, several state senators led despite spirited campaigns run by opponents. In Northwest Baltimore's District 41, Sen. Lisa A. Gladden led Park Heights community leader Will Hanna, who is wanted in Texas on theft charges.

Incumbent Dels. Samuel I. "Sandy" Rosenberg, Nathaniel T. Oaks and Jill P. Carter were ahead in races to retain their seats in District 41, as did Maggie McIntosh, Curt Anderson and Mary Washington in the 43rd District in North Baltimore.

In North Baltimore's District 40, newcomer Antonio Hayes led incumbent Dels. Frank Conaway Jr., Barbara Robinson and Shawn Z. Tarrant in races to retain their seats. If that holds, Tarrant would leave office after two terms.

In Southeast Baltimore's District 46, Democratic attorney Brook Lierman led a race to join incumbent Dels. Luke H. Clippinger and Peter A. Hammen.