George McGovern became what gay activists described as the first United States senator to make an appearance on behalf of the gay rights movement at an elaborate reception here Wednesday night.

The meeting, sponsored by the Los Angeles New Alliance for Gay Equality, was held to protest a proposed state referendum on a law sponsored by Republican gubernatorial candidate John Briggs banning the employment of gay teachers in California public schools.

However, the gathering also resulted in several impassioned attacks on the decision by Democratic Gov. Edmund G. (Jerry) Brown Jr. to fire the state's top drug abuse official for writing an allegedly obscene lesbian love letter on state stationery.

Some 1,000 persons, gathered at the grand ballroom of the elegant Beverly Wilshire Hotel, gave McGovern, the 1972 Democratic Party presidential nominee, a rousing ovation as he came to the podium. McGovern said the struggle for gay rights was a continuation of earlier battles for the rights of women and blacks and other minorities.

"I had to accept this invitation because of the basic principles you and I stand for in all the struggles against discrimination," the South Dakota Democrat said. "I don't think anyone needs to be told this is a controversial area, but I don't think there's any need for controversy over someone's freedom to personal privacy and against prejudice."

McGovern explained his presence at the reception by referring to a scene in "Alice in Wonderland" in which Alice asks Humpty Dumpty why he is alone, and he responds, "Because there is no one with me."

"I have come to this assembly," McGovern said, "because I don't want any Amercians to fell alone and deserted."

While it may be exceptional for a politician with a national profile to appear in front of a large, homosexual audience, there were enough local politicians around to prove that, in California at least, gay rights have already achieved base of support.

Among the sponsors of the New Alliance for Gay Rights (New Age) grouping, formed last summer in the wake of Anita Bryant's successful anti-gay rights drive in Florida, were Lt. Gov. Mervyn Dymally, Rep. Anthony C. Beilenson (D-Calif.) and Paul N. McCloskey Jr., (R-Calif.) three state senators, nine state assemblymen, Los Angeles City Attorney Burt Pines (now a candidate for state attorney general) and a small army of city council members, joined by a host of aspiring candidates to political office.

But the important thing about the rally, according to New Age organizers, was McGovern's presence, which they believe will give a greater national legitimacy to the gay rights movement. "It's a major breakthrough," said cochairman Syd Crocker. "This is the first time a national figure has espoused gay rights and countered the bigotry of Anita Bryant. After him, many other people will find the strength to do so."

Crocker said he expected McGovern to be among the first Senate sponsors of the Koch-Abzug Gay Rights Act.