Sen. Paul S. Sarbanes (D-Md.) held onto his lead in fund-raising against Prince George's County Executive Lawrence J. Hogan, his most likely Republican rival in the November election, according to reports filed yesterday with the Federal Election Commission.

Sarbanes reported collecting more than $950,000 and still had more than $350,000 left in his campaign warchest as of Aug. 30, the close of the reporting period. Hogan's report showed he had spent all but about $2,400 of the $292,000 he has raised since announcing his candidacy last September.

Hogan, however, said he is not concerned about Sarbanes' huge lead in fund-raising, asserting that he will make up ground once the Sept. 14 primary is over. Though he has no significant competition in the primary, Hogan said that political action committees and the national Republican Party have held back support until that election is over. After the primary, the party plans to pump nearly $250,000 into his campaign, and Hogan already has begun traveling the country to woo contributions from conservative and business groups.

In the 8th Congressional District, where conservative school board member Marian Greenblatt and her moderate board colleague Elizabeth Spencer are seeking the Republican nomination, the race has excited little interest among contributors, the reports showed. Greenblatt has raised about $32,000 and spent all but $2,000 of it. Spencer, who announced her candidacy just eight weeks ago, has raised only about $7,500, much of it from her own pocket. She has lent the campaign $5,000 and contributed $1,000.

Incumbent Democrat Michael Barnes, who has no challenger in the primary, was not required to file a financing report. Barnes had raised $160,000 as of June 30, the date of his last report.

In the 5th Congressional District, incumbent Democrat Steny Hoyer, who has no significant primary opposition, has raised $95,000. The report of his most prominent Republican challenger, the Rev. Perry Smith III, was not available.

In the Senate battle, where the National Conservative Political Action Committee (NCPAC) has targeted Sarbanes for defeat, the senator continued to garner large contributions from citizens around the country and to receive more than $60,000 from PACs, much of it from labor PACs who like his liberal voting record.

Hogan, a conservative whose challenge has recently been championed in NCPAC television commercials, has been counting on money from conservative and business groups. This past week Hogan traveled to California to woo money from conservative PACs. In the two-month period covered by the FEC report, Hogan had raised about $15,000 from an assortment of business groups. His largest contributor were the Republican National Senatorial Committee, which donated $15,000, and the group that championed Ronald Reagan's presidential campaign, Citizens for the Republic, which donated $5,000.