A Glen Burnie woman tried to buy secret in formation from the grand jury that indicted former Maryland Gov. Marvin Mandel in the belief she could sell the information to someone at an insurance firm owned by Mandel's closest friends, U.S. prosecutors said today.,tThe prosecutors' contention was made during the opening statements at the trial fo Donna Brown, which began in the U.S. District Court here today.

Shortly after the trial recessed, a lawyer for Harry W. Rodgers III, one of the owners of Tidewater Insurance codefendants in his political corruption trial, said that Rodgers had been approached by a man asking if he wanted grand jury information. Rodgers, the attorney, said "shut him [the man] off."

During their opening statements today, prosecutors charged that the woman on trial, Donna Brown, and a man she knew, hatched a "scheme" to attempt to buy grand jury information in 1975 from a grand juror who was Mrs Brown's "best friedn."

Brown's attorney, however, asserted that the alleged scheme actually was brough up by Brown as "a joke" that she was playing on her friend, Diane Lawrence. Brown, he said, "continued to carry it through" when Lawrence continued to press for details of the scheme.

Brown is charged with perjury, accused of lying to a second grand jury that investigated the alleged attempt to buy information.

Grand juror Lawrence immediately told federal prosecutors about the alleged approach and then worked with them to investigate it, prosecutors said today.

The 1975 grand jury on which Lawrence served ultimately indicted Mandel and five of his associates on political corruption charges. Three of Mandel's codefendants were owners of the Tidewater firm. They are Dale Hess, William A. Rodgers and Harry W. Rodgers III.

All six were convicted on mail fraud and racketeering charges in August 1977 and all had their convictions overturned on appeal three months ago.

Harry Rodgers' attorney, Thomas Green, said today that his client was approached at some point while the 1975 grand jury was in session by a man "asking if he was interested in receiving information." Rodgers told the man he "wasn't interested," Green said.

In court today assistant U.S. attorney Robert Trout charged that Warren C. Eastburn Sr., a Hartford County contractor, was "a middle person" in the scheme.Trout said that Eastburn "knew and was friendly with certain people at Tidewater."

Eastburn, whose wife said that he was in Delaware on business today, could not be reached for comment. He never has been indicted in connection with the alleged grand jury scheme, nor has any person at Tidewater been indicted in connection with the scheme.

Michael Marr, the attorney for William A. Rodgers, said yesterday that his client "never was approached by anybody in connection with any attempt to undermine the integrity of the grand jury."

William G. Hundley, Hess' lawyer, said today that his client never had been approached by anyone about buying grand jury information. He added that Hess did knoe Eastburn through business dealings.

The attempt to buy grand jury information, prosecutors told the jury today, "never came off. The money never came through and no information was disclosed."

Brown "thought she was on the verge of becoming a very rich lady by brokering this bribe with Diane Lawrence," Trout charged. "What she did not know was that her conversations were being taped."

Brown, 35, of Glenn Burnie, also has been accused of "influencing a federal grand juror," but that charge will be the basis of a separate trial.

Two men previously have been convicted of tampering with the trial jury that sat at the first, aborted trial of Mandel in 1976. The charges against Brown were the first accusations of an attempt to tamper with the grand jury that investigated Mandel.

The convictions of Mandel and his five codefendants were overturned last January by the 4th U.S. Circuit Court of Appeals.