Except in China, where she managed to pop into Peking's big Friendship Store, Nancy Reagan doesn't usually get a chance to go shopping in foreign capitals. When reporters asked what she was going to buy in Rome, she said she didn't have time. "You do all the shopping," she teased.

Larry Rubenstein, a United Press International photographer, decided to do something about that. He collected money from the press corps accompanying Mrs. Reagan, then went shopping for her. On the flight back to Bonn, Rubenstein made a presentation: red leather gloves.

Mrs. Reagan was delighted with both fit ("perfect") and color. "How did you pick the color?" she asked. And with the rest of her question, she may have planted the idea for a way to get the president's attention.

"The next time at a press conference are all the women going to wear red gloves?" she asked.

National Geographic Society photographers Jim Stanfield and Victor Boswell weren't taking any chances Saturday when Nancy Reagan arrived at the Vatican to visit Pope John Paul II. For a Vatican story the magazine is doing, the two photographers have installed a remote camera at the entrance to Sala Clementina, one of the rooms through which visitors pass en route to the papal library.

Earlier in the week the visitors happened to be Britain's Prince Charles and Princess Diana. And that should have made for some terrific pictures. Diana, however, spotted Boswell, whose job it was to trigger the camera with an infrared beam, and she showed an interest in the procedure.

"Nancy Reagan has more stage presence," Stanfield said, but even so, he and Boswell decided they wouldn't take any chances. Boswell was hidden around the corner when Mrs. Reagan walked past.

The Italian press' only sour note during Mrs. Reagan's visit was sounded by one of Italy's leading leftist dailies, La Repubblica. In a swipe at President Reagan's Bitburg visit, cartoonist Forattina portrayed the first lady at Mussolini's grave -- about to lay a wreath.

Identification of Nancy Reagan's 15-member entourage showed some White House ingenuity, if not some new titles. On the list submitted to Vatican officials, not only was a Secret Service agent given the title of "special assistant," but Mrs. Reagan's hairdresser, Julius Bengtsson, and her personal maid, Anita Costelo, were called "staff assistants."

Italy's fashion and film set, with some additional glitter provided by the Aga Khan and other titled types, did their bit (or their PR agents did) to keep speculation alive in Rome last week about whose party was upstaging whose for Nancy Reagan.

At their party Friday night, Ambassador to Italy Maxwell Rabb and his wife Ruth seated Mrs. Reagan between Rabb and Valentino, who is one of Ruth Rabb's favorite designers and provides many of her evening gowns.

At the luncheon Vatican Ambassador William A. Wilson and his wife Betty gave for Mrs. Reagan Saturday, she sat between Wilson and the Vatican secretary of state, Agostino Cardinal Caseroli.

The Rabbs probably won this round, if you add up names like Federico Fellini, Sophia Loren and Gina Lollobrigida in a crowd of 70. At the Wilsons, who reportedly managed to expand their entertainment space to accommodate 36 just in the nick of time, it fell to Audrey Hepburn to provide much of the glitter.

James Rosebush, Nancy Reagan's chief of staff, says the first lady's White House conference on drug abuse and her audience with the pope are "a preview" of what's coming in the next three years -- "though hopefully not all at once."

Rosebush says she isn't ruling out independent travel abroad as a means of circulating her message on drug abuse. Neither does he rule out more White House conferences with wives of foreign leaders.

Mrs. Reagan's schedule in Lisbon, where she and the president wind up their European tour later this week, has already been revised because of her drug conference. After Maria Manuella Eanes, wife of Portugal's president, asked her why she wasn't going to visit a parents group in Lisbon, White House aides scrubbed a sightseeing outing.

"They are scurrying around organizing a parents group for Mrs. Reagan to visit," Rosebush said of her Portuguese hosts.

Rosebush couldn't be happier about impromptu discussions leaders at the economic summit had about international cooperation against drug abuse.

"There they go," he quipped, "horning in on our issue."