The National Gallery of Art has announced five of the six exhibitions with which its new East Building will open on June 1. They are: "American Art at Mid-Century: The Subjects of the Artist," a loan show that will focus on the themes pursued by seven artists of the abstract expressionist generation. The artists and their subjects are: Arshile Gorky: "The Plough and the Song"; Willem de Kooning's "Women"; Robert Motherwell's "Elegies to the Spanish Republic;" Barnett Newman's "Stations of the Cross;" Jackson Pollock's poured paintings of 1950; Mark Rothko's "Brown and Gray Series" (never previously exhibited), and the "Voltri" sculptures made by David Smith in 1962.

"Piranesi: The Early Architectural Fantasies," a loan show of approximately 150 prints and drawings by Italian architect and draftsman Giovanni Battista Piranesi, who was born in 1720 and died 200 years ago.

"Aspects of the 20th Century Art," a three-part exhibition "limited to works of art owned by the Gallery or lent by major collectorswho have shown a special interest in the Gallery." "Picasso and Cubism," the first section, will include 40 works by Picasso and Cubism," the first section, will include 40 works by Picasso, Braque, Gris, Leger, Marcoussis, Feininger, Lipchitz, Gleizes, and Sculpture," the second section, will include 60 works "representing many of the dominant trends in modern art including fauvism, futurism, expressionism, surrealism, constructivism, and other forms of abstraction. Among the artists represented will be Matisee, Balla, Miro, Beckmann, Lehmbruck, Brancusi, Giacometti, Arp, Mondrian, Pevsner, Leger, Moore and Nicolson. The third portion of the exhibition will be partial encore of the recent show of cutouts belonging to the Gallery (among them "La Negresse" of 1952-53 and "Grand Decoration aux Masques" of 1953) will be on display, but this time accomapnied by the artists's "Jazz" series, which was not available for the cutout show.

"Small French Paintings from the Ailsa Mellon Bruce Collection," 60 impressionists and post-impressionists paintings given to the Gallery in 1970 by the late Ailsa Mellon Bruce, Andrew Mellon's daughter, who also helped to pay for the new East Building. Works by Bonnard, Boudin, Corot, Degas, Manet, Matisse, Monet, Pissarro, Renoir, Seurat, Sisley, Toulouse-Lautrec, Utrillo and Vuillard, will be included in the show.

Master Drawings and Watercolors: Selections from the National Gallery Collection and Promised Gifts." Among the artists represented will be Leonardo, Raphael, Michelangelo, Durer, Breughel, Rembrandt, Watteau, Blake, van Gogh and Degas.

The largest exhibition to open the new building will be "The Splendor of Dresden: 500 Years of Art Collecting," a loan show from East Germany that has not been officially announced.