About 25 elected officials and scores of office-seekers were among a crowd of about 550 last night who heard the Rev. Jesse L. Jackson call for unity in supporting candidates in the 1986 elections at a fund raiser for the Prince George's County Rainbow Coalition.

The elected officials included Maryland Gov. Harry Hughes, who showed up even though the state Rainbow Coalition last week endorsed one of his opponents, Rep. Michael D. Barnes, in the Democratic primary for U.S. Senate.

Hughes and other politicians at the fund raiser acknowledged that the track record of the coalition -- an offshoot of Jackson's 1984 presidential campaign organization -- in getting out the vote, especially in Prince George's and Montgomery counties, was an important reason they attended.

Besides announcing support for Barnes in the Senate race, the state's Rainbow Coalition last week endorsed state Attorney General Stephen Sachs for governor and Eleanor Carey for attorney general.

Jackson and Bennie L. Thayer, head of the Prince George's Rainbow Coalition, said that other endorsements will come after the formation of local and state steering committees that, in turn, will form the steering committee for the national Rainbown Coalition. The steering committees will be formed early next month, they said.

"We want to negotiate for change," Jackson said, "not broker for trinkets. We will end plantation politics. We can no longer have the Prince George's plantation in conflict with the Baltimore plantation, which in turn is in conflict with the Eastern Shore plantation."

The coalition's leaders said they eagerly are awaiting this year's elections, in light of the influence that the group had in 1984. That year, presidential candidate Jackson beat six opponents in the Democratic primary in Prince George's County. In the general election, Prince George's County was one of two Maryland jurisdictions won by Democratic nominee Walter F. Mondale. The other was traditionally Democratic Baltimore.

Although several political observers credited the coalition for those strong showings in 1984, Jackson warned the group not to rest on its laurels.

"The home runs last year do not count in this year's game," he said.

For most of his speech, Jackson focused on the problems of drug and alcohol abuse, urging the audience to begin cutting off the demand for drugs among young people rather than trying to cut off the supply of illegal drugs. Sensing a bit of restlessness in the crowd Jackson then switched to political issues.

"I know you want to hear me talk about politics and supporting X candidate," he said. "That's important. But people on drugs don't register, don't vote, don't have stamina, don't have perseverance. People who are sober and sane will get involved in politics."

Barnes, a Montgomery County Democrat, said that Jackson will be back in the state to campaign for candidates endorsed by the coalition.

"Even without the Rev. Jackson on the ticket, the coalition's candidates are going to be a powerful influence in this year's elections," Barnes said.