Spurred by citizen demands to stop the march of downtown highrise office buildings into the Dupont Circle neighborhood, the D.C. zoning commission agreed yesterday to several zoning changes that would limit the heights of new buildings along several important streets in the area.

But the sharply divided commissioners sidestepped the major change proposed by a coalition of citizens groups - the downzoning of Connecticut Avenue north of the circle to Florida Avenue.

A coalition of Dupont Circle civic group battled for their community, a residential-commercial area crowded with small shops, restaurants that range from the chic to the seedy, art galleries, clubs and bookstores. The neighborhood has been home to a mixture of races, ages and income groups over the years. During the late 1960s, it became a sort of "hippie haven." Increasingly, it has become an affluent area of renovated rowhouses and homes, some of which sell for more than $150,000.

After quibbling over the proposal, the three zoning commissioners who voted on the case decided to remove the Connecticut Avenue decision from the over-all Dupont Circle rezoning case and consider it another time.

The changes that were approved yesterday will significantly affect the future look of new buildings in the Dupont Circle area between Florida Avenue, M, 15th, and 23rd streets NW, covering 6 acres. Those changes include:

Reducing to 65 feet the heights permitted on 16th Street from Scott Circle to Q Street, where 90-foot heights now are permitted.

Reducing from 90 to 65 feet the heights of new buildings permitted on Massachusetts Avenue between 20th Street and Florida Avenue NW and on the south side of Massachusetts between Dupont and Scott circles.

Reducing from 90 to 65 feet the heights of buildings on New Hampshire Avenue from Dupont Circle to R Street.

Reducing to 65 feet the heights permitted on 20th Street between P and Q Streets, with 50-foot heights permitted on parts of the east side of that block. Currently, 90-foot heights are also permitted there.

Reducing to 65 feet the heights permited between on the west side of New Hampshire Avenue between Riggs Place and Swann Street.

Incresing heights from 50 to 65 feet on 17th Street. Currently, only 50-foot heights are permitted. The citizens groups had asked for such an upzoning.

But Connecticut Avenue was the major change the citizens wanted, and they were disappointed with yesterday's postponement.

"They quite really cut the heart out from us," said Susan Meehan, an advisory neighborhood commissioner and long-time Dupont activist. "We'll just have to try to keep our chins up."

Anne Sellin, spokesman for the coalition, said, "The area under the most pressure is not protected." The Connecticut Avenue strip has become a prime target for commercial development.

Sellin said she considered yesterday somewhat of a disapointment in other areas as well. The citizens group didn't get 16th Street from Q to U Street NW downzoned, she said, in addition to several other areas.

The coalition proposals were opposed by numerous property owners, developers and businessmen who testified that the changes would lead to the erosion of the city's tax base and would have an adverse impact on jobs and transit revenues at the Dupont Circle metro station.

The zoning commissioners suggested to the staff that a new zoning category be created for Connecticut Avenue, one that might involve lowering heights but which would encourage commercial rather than residential uses.

At two meetings in March, the commissioners had tentatively agreed to reduce the Connecticut Avenue heights to 50 or 65 feet.

But yesterday, commissioner George White, noting that a new city law provides historic preservation of buildings, said the proposed zoning category would wrongly encourage residential use on what is essentially a commercial strip. He supported leaving the zoning categories unchanged. Commissioner Lewis indicated that he supported White's position.

But commissioner James Parson argued, "In no way am I going to (accept) 90 feet...I'm really disappointed..."

Only three of the five zoning commissioners participated in the hearings, so by law they had to agree unanimously on changes to effect them.

Zoning attorney Norman Glasgow represented many of those opposed to the proposals. He said yesterday's decisions will have a "significant" negative impact on some of his clients.

For example, Glasgow said, the First Baptist Church at 16th and O Streets NW, the church attended by President Carter, wants to construct a new building immediately west of the church. "This is a very serious blow to them," Glasgow said. "They probably won't be able to carry out their long-range plans."

Glasgow said he would continue to fight any rezoning of Connecticut Avenue when hearings resume.

The changes approved yesterday will be sent to the National Capital Planning Commission for its report on the federal impact.