Gordon Peterson moderates "Inside Washington.” ( WJLA /WJLA)

“Inside Washington,” the news panel-discussion TV program that spawned countless imitators — including a few at higher decibels — will end its run after more than 40 years on the air.

Gordon Peterson, the WJLA news anchor who has hosted the show for the past 25 years, said production will stop in late December, ending a program that began with host Martin Agronsky in 1969.

Originally called “Agronsky & Co.,” the show was a pioneer of the “talking head” format in which a panel of journalists and other pundits give their views about the news instead of interviewing newsmakers. Dozens of such programs — which are inexpensive to produce and attract small but affluent audiences — air on broadcast and cable channels.

“Inside Washington’s” demise comes just as one of its many descendants, “Crossfire,” is being revived by CNN. The cable network aired the political debate program from 1982 to 2005 and is rolling out a new version Monday. It will feature former House speaker Newt Gingrich (R-Ga.) and conservative commentator S.E. Cupp taking turns representing the “right” against alternating hosts from the “left,” Democratic strategist Stephanie Cutter and civil-rights activist Van Jones.

Peterson, 75, will continue as an anchorman at WJLA, the ABC affiliate in Washington, where he just signed a new contract.

He said he’s thought several times about ending “Inside Washington,” including after the 2008 election. But he kept going, encouraged by feedback from viewers.

“I really love this thing,” he said in an interview. “But I don’t want the program to get old. I don’t want it to get stale. I thought 2013 was a perfect time to stop,” with a presidential election three years away and after 25 years as host.

He described the show as “a lively after-dinner conversation, where some smart people sit around the table and talk about stuff” — typically in a less combative way than on “The McLaughlin Group.” The latter program copied “Agronsky’s” formula but made the discussion more opinionated and noisy.

Over the years, “Inside Washington’s” panelists have included many who became widely known for slinging opinions on similar programs, including “McLaughlin.” The list includes James J. Kilpatrick, Carl Rowan, Jack Germond, Hugh Sidey, Strobe Talbott, Elizabeth Drew and Washington Post columnists Charles Krauthammer and George Will.

Current panelists include Krauthammer, Washington Post columnist Colbert King, NPR’s Nina Totenberg, former Newsweek editor Evan Thomas and columnist Mark Shields. Four of the five appear each week.

Allbritton Communications produces “Inside Washington” and owns two of the stations that air it in Washington, WJLA (known as ABC7) and local cable network Newschannel 8. The show also airs locally on public TV station WETA and is syndicated to public TV stations across the country.

Peterson said the decision to end the show was unrelated to Allbritton’s sale of WJLA and Newschannel 8 to Sinclair Broadcast Group. Sinclair said in July that it would acquire Allbritton’s seven TV stations and Newschannel 8 for $985 million.

But he said Allbritton has “kept it afloat” since 2004, when Peterson left WUSA, channel 9, in Washington to join WJLA as an anchor. WUSA, formerly known as WTOP-TV, had produced the show until that time.

Peterson laughed heartily recalling the by-play over the years among the show’s panelists, on and off the air. “Every once in while, Charles [Krauthammer] would become irritated by something someone said, and he’d say, ‘This is just more liberal echo-chamber elite cocooning!’ ” said Peterson, repeating the odd phrase.

He also was amused by a recent comment made by Shields, who said that rotund New Jersey Gov. Chris Christie (R) “took longer to get out of his SUV than the Russians took to get out of Afghanistan.”

“I’m just sorry we couldn’t do a program about what goes on in the green room or during the breaks,” Peterson said.

Peterson said he didn’t know about the program’s ratings in syndication. “They keep us around, so they must be okay,” he said.