Reeling from cartoonist Garry Trudeau's decision to take a breather from penning the antics of the Doonesbury gang, Universal Press Syndicate president John P. McMeel yesterday urged the public to "write letters to Garry to come back" soon.

Trudeau's "long-term" contract with the company, signed in 1970, included an option to take a holiday from the daily comic strip if he so desired. "We kept crossing our fingers that he wouldn't exercise it," McMeel said in a press conference yesterday at the syndicate's Fairway, Kan., office.

During Trudeau's sabbatical, which could be for as long as 20 months, he plans to write and study and is working on a Doonesbury musical for Broadway, McMeel said. "He wants to bring back a bigger and better Doonesbury," McMeel added. "But how you improve on perfection, I don't know."

McMeel called Doonesbury a "vital part of 20th-century Americana." He recalled how the popular comic strip got off to a slow start in the early 1970s because of its radical and progressive nature.

Standing in front of a huge black-and-white portrait of the 34-year-old cartoonist, McMeel revealed the only Doonesbury strip never to make it out of the drawing room.

It portrayed Michael Doonesbury espousing the merits of marijuana and getting high only to have his friend Mark Slackmeyer point out in the last frame that the "joint" was not even lit.

The comic strip is currently published in 700 newspapers in the United States and Europe.

Nancy Reagan telephoned the first lady of Peru yesterday to ask that authorities speed up adoption procedures for a 3-year-old Peruvian orphan who underwent delicate heart surgery at a Boston hospital.

A Quincy, Mass., couple wants to adopt little Anita Asto, who was born with only three of four chambers in her heart and a malfunctioning pulmonary valve. She was operated on yesterday at Boston's Children's Hospital and emerged in good condition.

Robert Ulchak and his wife, Diane, brought Anita to the United States for medical treatment after learning of her plight while adopting a little boy 14 months ago in a Lima orphanage.

Anita is in the United States on a 90-day medical visa that expires Oct. 16. The Ulchaks, hoping to adopt the young girl, have written Mrs. Reagan in an effort to reduce red tape.

Mrs. Reagan's press secretary, Sheila Tate, said the first lady telephoned Violeta Belaunde, wife of the Peruvian president. Mrs. Belaunde said she talked to top government officials on what can be done to speed up the adoption and a recommendation has been made to expedite the case.

The condition of former first lady Bess Truman worsened again yesterday and she was listed in serious condition at the Research Medical Center in Kansas City, Mo. Dr. Wallace Graham said, "At the moment Mrs. Truman is stable," but added that due to her continued bleeding ulcer her blood pressure dropped, her pulse quickened and her temperature increased during the night.

Country singer Johnny Paycheck filed for bankruptcy again yesterday -- 30 minutes before the Internal Revenue Service planned to put three of his guitars and other personal belongings on the auction block.

The move blocked, at least for the time being, IRS efforts to collect on a $103,000 lien it has placed on Paycheck's property for nonpayment of taxes.

Paycheck, whose song "Take This Job and Shove It" became an anthem for disgruntled workers, did not reveal his total indebtedness in his bankruptcy petition, but listed 19 creditors.

One of President Lyndon B. Johnson's gray western hats will be auctioned tomorrow to raise money for a boys' home near the Hill Country ranch outside San Antonio, Tex., which Johnson loved and enjoyed.

Auction organizers hope the hat will fetch about $15,000, said Ray Neumann, a spokesman for Boysville. Neumann also said he would like exceed the $105,000 collected from last year's auction.

Johnson's Triple X Beaver hat, manufactured by Resistol, is pale gray with a leather hatband imprinted with "Made expressly for Lyndon B. Johnson" in gold. On the white silk crown is a map of Texas in gold with "LBJ Ranch" written across it in blue. It was donated by Lady Bird Johnson.

Movie ticket sales this summer totaled a walloping $1.4 billion, with "E.T. -- The Extra Terrestrial" raking in $240 million -- 18 percent of the total summer take.

Summer seasons are measured from Memorial Day weekend through Labor Day weekend. This year's tally exceeds the previous record of $1.23 billion set in 1981.

"Rocky III" brought in $111 million, followed by "Star Trek II," $76 million; "Poltergeist," $65.7 million; "The Best Little Whorehouse in Texas," $60.7 million; "Annie," $52.7 million and "Conan the Barbarian," $50 million.

Georgia State Sen. Julian Bond said earlier this week that money -- "the mother's milk of politics" -- or lack of it, is why he's abandoning his current bid for the U.S. Congress.

Bond, a black civil rights activist who helped reapportion the Fifth Congressional District to include a 65 percent black majority, said he failed to secure adequate financial support to campaign in a special Democratic primary in late fall.

Last month Bond said he would challenge incumbent Democrat Wyche Fowler, who is white and now unopposed in the race.

British Prime Minister Margaret Thatcher said she does not oppose divorce, even when there are young children to consider. According to an interview published in the British magazine Woman, Thatcher, mother of 29-year-old twins, said she knows "many families where, frankly, it divorce was better for the children.

"You can never quite know what goes on behind someone else's front door, and cannot set out to judge," Thatcher told the magazine.

Trying to quit smoking during times of stress can be tough, as West German Chancellor Helmut Schmidt has found out. According to spokesman Klaus Boelling, Schmidt "has been smoking again for a couple of weeks now."

The West German leader, 63, kicked the habit after having a pacemaker surgically implanted last autumn. Schmidt's much publicized New Year's resolution was "never again."

Nevertheless, rumors about the imminent collapse of the coalition government formed of Schmidt's Social Democrats and the Free Democratic Party have driven the party chief to resume his old habit. "But it's just a few cigarettes a day," added Boelling.

One of Adolf Hitler's ceremonial shirts and his personal flag, which was to be auctioned in New York, were withdrawn from sale yesterday after auctioneer Charles Hamilton announced he received threatening phone calls at the Sheraton Hotel, where the auction was to take place. He added he was now going to suggest the items be donated to Israel's Holocaust museum because "these are war mementos."