In a flurry of activity this pring, Harper's Atlantic Monthly and Saturday Review, three of the nation's oldest magazines, were put up for sale at distress prices, raising new doubts about their ultimate survival, but bringing at least two of them new owners with deep pockets.

Quality, thoughtful magazines once sailed untroubled seas, confident of their roles and futures, but in recent years some have foundered in the shifting economic and cultural tides while others have found themselves remade by new backers as often as chorus girls change costumes.

While the American Show Beagle, the Harvard Business Review and other magazines devoted to such interests as fly fishing, marine biology, model railroads, the Civil War and hundreds of other fields have grown prosperous, publishing most of the oldline periodicals became an expensive task in the 1970s.

The 1980s could be worse, but Robert Weingarten, who bought Saturday Review, and Mortimer Zuckerman, who bought Atlantic Monthly, are confident they will make money.

At the same time, Weingarten, 38, and Zuckerman, 42, are self-made men who, although they will devote a lot of time to their new magazines, will retain other revenue-producing properties.

There is about each of their resumes much more of the businessman than the literary figure, but they share what is apparently the most basic qualtiy needed by a magazine publisher -- they are their magazines' audience. They like what they now own.

Zuckerman, who concedes he sounds like a Boy Scout on his first cookout, said in an interview that "publishing a magazine is making your enthusiasms public."

He explains his enthusiasms by turning to traditions of the Atlantic. Zuckerman reads aloud from the 123-year-old monthly 100th anniversary issue reflections on its past with pride and affection.

Zuckerman, a developer whose hugely successful Boston Properties has been active all over the country and in Washington has a project near L'Enfant Plaza, said he intends to see the Atlantic through the rest of this century.

"I don't intend to have my life defined by putting up another 40 buildings," he said.

"The Atlantic is as much fun as anything I've ever done in my life," Zuckerman added. It is also made worthwhile by the fun, not the money. "On economic grounds alone, I wouldn't have bought it," he said.

He intends to continue publishing fiction and poetry as well as nonfiction articles and is signing up writers as regular contributors. His first two are biologist Dr. Lewis Thomas who wrote The Lives of a Cell and syndicated columnist Ellen Goodman.

The Atlantic has a circulation of about $35,000 and advertising revenue is running about 10 percent above last year. It had been losing money for only two years and Zuckerman said last year's loss was considerably below $500,000, although he would not name a figure.

Atlantic Monthly was the soundest of the three magazines that came up for sale this year, according to a man who looked at all of them and bought none.

Weingarten, unlike Zuckerman, has specific plans to alter his new magazine as rapidly as he can. He is going to take Saturday Review out of the competition with Atlantic and Harper's and write only about literature and the arts as it did during its successful years under Norman Cousins before 1971.

"There is a natural mandate for Saturday Review," Weingarten said in an interview. "The people who lost money with Saturday Review were people who ignored the mandate."

Weingarten is pleased by the attention his purchase has gotten. Time magazine called Saturday Review august, Newsweek wrote respectfully of its readers' loyalty and Weingarten takes the press coverage as evidence he is right in thinking that Saturday Review has "the greatest name of any cultural magazine."

Weingarten has his doubts whether there is going to be a 1980s market for the general magazine like Harper's and the Atlantic, but the former Wall Street broker who publishes a successful magazine for investors, Financial World, is bullish on culture.

"I think that culture, which has been a pretty cool world to Madison Avenue, is actually the greatest growth industry in the United States," Weingarten said.

He ticks off his reasons for being upbeat; More people went to museums than sporting events last year; art galleries are having more visitors and selling more; concert audiences are growing; art object values are climbing, and book sales have soared.

The first example of the approach of Weingarten and his editor-in-chief Alfred Kingon will be on display in the June issue.

The June cover story they inherited was on casino gambling. There was no time to commission a new cover, but a short article set to run in the back of the June issue raised questions about James Levine's abilities as musical director of the Metropolitan Opera.

They asked the author to expand it and put Levine on the cover. The casino gambling article was scrapped.

Weingarten plans to reduce Saturday Review costs by efficiency of scale since he owns other magazines. It will also be cheaper to print monthly rather than biweekly as his predecessor did.

Even in a world of specialty magazines, Weingarten said, the roughly 520,000 Saturday Review subscribers want a magazine that synthesizes. One reader may be a specialist in one branch of the arts, but he will still want Saturday Review for its coverage of the other branches, Weingarten said.

"I am the Saturday Review reader. I am the market," Weingarten said. He plays the violin, met his wife in an orchestra, spends most of his free time reading and attends concerts and the theater regularly, he said.

That gives him confidence that he knows what he is doing. Weingarten once was offered Redbook at an attractive price and turned it down. "I'm not a Queens housewife. I can't understand a Queens housewife," he said. "I want to be interested in what I'm producing."

Harper's, the nation's oldest monthly at 130, has yet to find a buyer, Otto Silha, president of the Minneapolis Star and Tribune Co., said, "We've owned Harper's for 15 years and it's never been a true success. We want to leave it in the best shape possible."

Harper's had losses of more than $1.5 million last year and is the rockiest of the three magazines, according to men who have seen its books. There are many who think it will not survive long.

Last week, Ira Silverman, a wealthy Princeton, N.J., specialist in public affairs, dropped out of the bidding for Harper's, leaving its editor, Lewis Lapham, as the most serious contender.

"It is clearly as extraordinarily risky venture,' Silverman said after he abandoned his effort to buy Harper's. "I'm not a corporation. I'm not in a position to underwrite eternal losses."

He emphasized, however, that it was the risk, not the ultimate result that frightened him away. "I believe it is doable. Harpers has an enormously attractive history and could have an attractive future," he said.

Harper's fate seems likely to be decided within the next two weeks. Lapham strongly rejects the contention that Harper's is in worse shape than the Atlantic or Saturday Review. He said it could be turned around by raising its price so that the readers, not the advertisers, pay the freight.

The circulation would drop from its current 330,000, but would reflect a more affluent group, more attractive to advertisers.

Competition for the advertising dollar has gotten tougher, Lapham noted. Not only are their specialty magazines, newspapers, radio and TV, but he took his son to Yankee Stadium for Bat Day and found the giveaway bets featuring a men's toiletries company's name where bats used to say "Louisville Slugger."

Rising cost of paper, ink and postage have hurt all magazines. Newspapers have invaded the turf of the general magazines with opinion pieces on their op-ed pages and Sunday sections. "60 Minutes" calls itself a magazines show.

American life has changed and time for reading may be given to other journals or to books. For the editors of monthlies it has become harder with events moving so fast -- to predict in April what will read well in June. Writing about ideas may not play well in the United States of 1980 unless it comes wrapped in scholarly quarterlies with special approaches.

The educated and literary audience that looked to Boston or New York to to get a purchase on the cultural scene before World War I has broken up into groups with different preoccupations.

All this contributes to what Harper's would-be-seller, Silha, described as "a lack of intensity of interest in the reader audience and advertising fields." Yet, judging from this spring's buying and selling, the lure of owning a magazine and attempting to rekindle interest in a venerable publication appears to run strong.