Maryland Gov. Marvin Mandel may have suffered a "mild stroke" that would make it unwise for him to go on trial next week on political corruption charges, his doctor said yesterday.

Dr. Perry Hookman, director of medical education at Prince George's General Hospital, said preliminary tests indicate that "this is simply not just a case of exhaustion" as originally suspected when Mandel was hospitalized Tuesday.

"I believe this could have been a stroke," he said at a late afternoon press briefing.

The diagnosis, he stressed, was tentative, based on motor weaknesses detected on Mandel's right side and momentary losses of memory the governor reported during the recent weeks. Hookman brought in two neurologists as consultants on the case and said that they are examining the possibility that the governor may have developed some sort of tumor. Further examinations are expected today.

Hookman said that Mandel, 56, was in good spirits, resting peacefully in a ninth floor room of Prince George's Hospital in suburban Cheverly.

"The governor is cheerful, he's cooperative, he's optimistic and he's raring to get out," Hookman said.

Mandel's wife Jeanne, who divided her time between Annapolis and the hospital room yesterday, said the governor suffered his latest memory lapse Monday while testifying before a congressional committee on the Appalachian Regional Commission "I don't want to go into it, but that wasn't the first time," she said.

The exact impact on the governor's second trial, scheduled to begin next Wednesday, was unclear. If Mandel did actually suffer a stroke, Hookman said the treatment would be "observation." "My own opinion is if a person has had a stroke he shouldn't be put under stress and strain," he added.

The case, pending against Mandel and five codefendants since indictments were returned in November, 1975, has been marked by a bizarre series of delays and occurrences, including a mistrial declared last December after two jury tampering incidents.

The governor is the second defendant to develop health problems. Last September, the trial of Irvin Kovens, a millionare political kingmaker, was severed from that of the other defendants after he developed a heart ailment. Kovens is scheduled to stand trial with the others this time.

What is commonly referred to as a "stroke," said Dr. Richard Edelson, chief of neurology at the Washington Hospital Center, is the reduction or loss of some power or ability controlled by the brain," the sudden onset of a neurological deficit."

The common signs of stroke are problems in controlling limbs or speech problems, said Edelson, a partner in private practice with Dr. Marvin Korengold, one of the specialists who examined Mandel.

A stroke is usually caused by a reduction of blood flow, and thus of oxygen supply, to some area of the brain.

Mandel's ailment also removed the chief executive from the State House during the crucial final week of the General Assembly. His administration was battling to preserve the three most important elements in the governor's legislative program: a one percentage point increase in the state sales tax, his budget and a $26 million appropiration for a new prison in Baltimore.

Mrs. Mandel said yesterday she met five hours yesterday with the governor's staff and was overseeing his interests in Annapolis. "I'm his eyes, legs and arms, doing all the things he normally does," she said.

"I have to be able to anticipate all the questions he asks me here," she said. "I'm trying to keep him in complete touch."

Lt. Gov. Blair Lee, however, downplayed Mrs. Mandel's role. He said that he and Alan M. Wilner, the governor's chief legislative aide, and several members of the governor's staff met about noon to draft memos for Mrs. Mandel to take to the hospital.

"Nobody presided," Lee said, "but Mrs. Mandel graciously consented to be a courier."

Mrs. Mandel and state troopers assigned to guard the governor's room were apparently the only nonmedical people to talk with Mandel yesterday. She said she had put on a wedding band belonging to the governor's mother when he was taken to the hospital Tuesday. It was the first time she had worn the ring, and it gave her a sense of inner peace, she said. "I hope she's up there watching what's being done to her son, and she's praying for us."

Hookman's tentative diagnosis of a stroke was not confirmed by other doctors in the case.

Korengold, professor of neurology at George Washington University Medical School and past president of the D.C. Medical Society, said he had examined Mandel but doesn't "know that any conclusions have been reached except that he's undergoing some diagnostic tests.

"Until you have all the facts in hand, the rest is speculation," said Korengold when asked if Mandel had, in fact, suffered a stroke.

"I don't feel I would want to comment," he said, "because we're trying to draw a conculsion of what a picture looks like when only a few pieces are there . . . The symptoms might be due to many different things."

While Korengold refused to speculate as to whether Mandel suffered a stroke, he did say he believes the governor's symptoms are genuine.

"I believe there is a physical basis for his symptoms," said Korengold. "I've heard speculation that this is not a physical ailment, but there are definitely physical signs."

Dr. George B. Udvarheyl, professor of neurosurgery at John Hopkins in Baltimore and former acting chairman of neurosurgery there, is the second consultant called in on the case. He could not be reached for comment.

Mandel is expected to remain in the hospital until at least Friday undergoing tests.

Meanwhile, the state legislature moved into its final days, acting like a ship without a captain. "I've never had a day like this," said Lt. Gov. Lee, who kept in touch with the governor through Mrs. Mandel. "I'm already getting return flack," Lee added at midday, explaining Mrs. Mandel had called him with instructions from the governor.

Lee said he can conduct the routine duties of a governor without any special authorization, but it is necessary for Mandel to write a letter instructing him to become "acting governor" for him to assume other duties, such as bill signings.

Lee has assumed these duties several dozen times in the past while Mandel has gone out of the state on various trips.

The chief legislative measure still up in the most of yesterday was the governor's sales tax proposal pending in the House of Delegates.

The question of whether to bring the sales tax up for a final vote today was left in the hands of Lee, House Speaker John Hanson Briscoe and Del. Paul E. Weisengoff (D-Baltimore), leader of the largest delegation in the House.

Just before the start of today's evening session in the House, Weisengoff said, "We're within 10 votes and going up (getting close)." He admitted the job would be easier if Mandel were available to talk to individual delegates. "Marvin has a way of explaining things better than most legislators," laughed the cigar-smoking Weisengoff.

"Yeah, no deals can be made," aid another delegate. "These guys (Briscoe, Weisengoff and other House leaders) can't offer schools of judgeships."

Del. William M. Linton (R-Baltmore County), the House minority leader, said "No question they (tax increase supporters) have lost their best negotiator."

But Linton added that "like any company, middle management can carry on for a considerable period of time."

While the sales tax loomed as the single most important unresolved question, Del. Donald B. Robertson (D-Montgomery) said that "I can visualize situations where critical issues would arise that could tie up the Assembly.

It is in those situations that Mandel has been at his best as a negotiator, Robertson observed.

The chairman of the Baltimore County delegation, Del. Daniel J. Minnick Jr. said "We all do it in jest (remark about the timing of the ailment) but he's under a big strain.A trial would be a strain on any of us but Marvin hides his feelings, you don't know."