When Nancy Marchand was summoned to an appointment at CBS in New York a couple of years ago, she showed up with Muggsy.

She had been told that she was being considered for the role of a brassy newspaper publisher in the new CBS series "Lou Grant," and that the character seldom went anywhere without her dog. So Muggsy, a miniature wirehaired dachshund, came along.

The guards posted in front of the CBS elevators were not impressed by Muggsy. No dogs allowed, they said.

All right, replied Marchand. The guards would just have to tell the honchos upstairs that Nancy Marchand would not be able to see them until Muggsy could see them too.

Within minutes, a vice president of CBS was downstairs welcoming Muggsy and his mistress to the network. Soon enough, Marchand had been cast as Margaret Pynchon, ruler of "The Los Angeles Tribune" on "Lou Grant."

Mrs. Pynchon is a familiar emblem to many American journalists, and Marchand was in Washington to help swear in the new officers of the National Press Club Sunday night.

It was her first such ceremony, she said. Normally she does not go out of her way to mingle with journalists. "If I'm playing a psychotic," she explained, "I don't fill myself up with pills and stalk people through the streets."

She does a lot of reading as research for her role. "Now that I'm in the paper business," she said "I really read the paper. It takes me until 11 a.m. every morning to read The New York Times. Then, by late afternoon I don't remember one thing I've read."'

Though "Lou Grant" is shot in Los Angeles, Marchand lives in New York and loves it: "I like the dirt, the smells, the people, the pigeons, the exhaust, the energy, the hysteria."

She has been a New York stage and television actress for years, but she hasn't done commercials. "I have a mental problem with them," she said. "I don't take them seriously, and the people who make them do."

It's hard to imagine Mrs. Pynchon having anything to do with commercials -- or with dirt, smells, pigeons or exhaust, for that matter. But Marchand thinks "the other part of the world is very fascinating" to the wealthy and dignified publisher.

Marchand requested a scene that would put Mrs. Pynchon in the noise and grime of the pressroom, she said. But she was told the set for such a scene would be too expensive.

At 50, Marchand is 10 years younger than Mrs. Pynchon, and she dresses in a more contemporary style. Without her Mrs. Pynchon wig, Marchand is a redhead. She looks remarkably like Ford's Theater producer Frankie Hewitt.

Yet she is familiar with "the invisible shell" that surrounds Mrs. Pynchon. "Until recently this country was so gerrymandered that any middleclass WASP was simply very protected," said Marchand. She was one of these creatures herself, the daughter of a dentist and a pianist in Eggertsville, N.Y., a Buffalo suburb.

Marchand's childhood nickname was "Nun." It was bestowed on her "by some silly girls," and she can't remember why. There were no nuns in the neighborhood. "We only had the royal WASPs on my side of the tracks," she recalled.

From Sunday school Marchand picked up the impression that Jews "were an extinct tribe," she said. "We learned that they did wonderful things, crossing the Red Sea and all, and that they were the foundation for the Christian religion, but it was implied that they had died out."

Only when Marchand saw "the stuff with Hitler" in the newsreels at the movies -- "which I attended every spare minute" -- did she realize Jews were still around. But that was a long time ago. Actor Paul Sparer, her husband of 28 years, is Jewish.

Marchand went to Carnegie Tech and then New York City. Her big break was a performance as Jo in a "Studio One" rendition of "Little Women." She appeared frequently on live television and did radio comedy sketches with Jonathan Winters. She made the rounds of soap operas.

Several years ago she was a regular on the short-lived but much-discussed "Beacon Hill." Now she says she doesn't believe her aristocratic "Beacon Hill" matron would ever have married into an Irish family in the first place. So much for "Beacon Hill."

Her stage work frequently brought Marchand to the National Theater in Washington, and at every performance here there was always a man with black kid gloves, steel teeth and a cane near the front row. After the show he would find her and "talk and talk and talk about all these mysterious experiences." This character almost made her swear off Washington.

Marchand and Sparer have three children and Muggsy. Despite the doors that opened for Muggsy at CBS, however, he does not play Mrs. Pynchon's dog on "Lou Grant." Two Yorkshire terriers have been cast in that role. The first one was unhappy in the role because it required a separation from Lassie, his best friend, according to Marchand. So after the first season, a new and "much happier" dog was brought in.

Marchand doesn't think any viewers noticed the casting change."When you've seen one Yorkie, you've seen 'em all," she said.

Mrs. Pynchon would not approve.