Changes are in store on the P Street strip of commercial galleries between Dupont Circle and 22nd Street NW.

Gallery Rebecca Cooper, 2130 P St. NW, has gone out of operation. One reason for the closing is that Cooper, who showed the California visionaries and other contemporary surrealists, was hospitalized last September following a fall. She could not be reached for comment, but her husband, attorney Alan D. Eisenberg, said that "though she is feeling fine now, she is giving up her space."

Victoria Fortune, who showed art nouveaul and art deco at 2035 P St. NW, has moved her shop to Arlington where it will soon reopen -- but by appointment only. Fortune, whose new address is 1600 S. Eads St. in the North Building of Crystal Towers, says that street traffic on the strip provided only 15 percent of her business and that poportion has recently diminished because the only nearby parking lot has gone out of operation.

The Wade Gallery, which is not on the strip but near it at 1726 21st St. NW, has gone out of operation. Carol Wade, who declined to discuss the reasons for her closing, did acknowledge that her building is being sold.

Dealers Luis Lastra and Ramon Osuna, co-owners of the Pyramid Galleries Ltd., have dissolved their partnership. Lastra has gone into business as a private art consultant. Osuna, who has formed a new corporation, will remain in business at 2121 P St. NW. His gallery is now called the Osuna Gallery, Inc.

Additional changes are expected.

Middendorf/Lane, 2014 P St. NW, will move when the season ends in spring. Owners Chris Middendorf and Palmer Lane will reopen in September a few doors from Connecticut Avenue at 2009 Columbia Rd. NW in a building constructed in 1900 as the Greek embassy. The building will have a back-yard sculpture garden, 12-foot ceilings, and 4000 square feet of exhition space. It is soon to be restored.

The large apartment building at 2121 P St. NW, which houses the Pyramid, Hom, Foundry and Jane Haslem Galleries also has been, of late, the subject of many rumors. According to one rumor, the building eventually will be turned into a residential hotel.

Of the galleries in the building, Haslem's which is adjacent to the lobby, is in the most vulnerable location.

"People have been coming into my gallery saying, 'We might take this part for the lobby, this part for new offices, this part for a new entrance to the restaurant.' Last July my landlords would grant me only a one-year lease renewal. I wonder what's going on.

"My landlords, Stuart A. Bernstein and Co., have always been kind and sympathetic. But still I'm worried," Haslem said. "Most of my exhibits are planned a year ahead. I can't move on short notice. I've asked my lawyer to ask the Bernsteins to promase me at least six months warning if they plan to take my space."

Leon Bernstein, asked if the hotel rumors were true, said, "I can't discuss that." He added that "If the building becomes a hotel -- and I'm not saying it will -- I think the galleries would be an attraction. We have no present intention to change any commercial space. And we certainly would give our renters ample notice if we had to move them out."

Other dealers on the strip note the neighborhood is changing, that land values are climbing, and that many nearby older buildings are undergoing renovation.

They also are aware that developers Robert Lennon and Stanley Westreich plan to lure a number of the city's more successful galleries to "Gallery Row," a group of 19th-century buildings on downtown 7th Street NW.

"We've completed negotiations with the Pennsylvania Avenue Redevelopment Corporation," Lennon said. "We expect to sign a 99-year lease on Feb. 15. Renovation would begin in May. As of now we plan to open in May of 1980. We'll have space for 10 to 14 galleries. I would expect that some of them would move downtown from the P Street strip."