Gov. Marvin Mandell was admitted to Prince George's County Hospital for observation yesterday, eight days before he is scheduled to go on trial for the second time on political corruption charges.

Dr. Perry Hookman, the governor's family physician, said Mandel, 57, was suffering from acute headaches, fatigue and a motor weakness in his right side. The symptoms, he said, could be due to "severe exhaustion or some organic disease."

Hookman, who has examined Mandel weekly for the last month, said the governor had called him late Monday night complaining that "headaches were preventing him from sleeping." He said the governor had also told him that he'd had "interruptions in his train of thought" several times in the last month.

At a press conference at the Cheverly hospital, Hookman said he had been trying to hospitalize Mandel for three weeks, but the governor had refused. he estimated that Mandel would remain in the hospital for three or four days undergoing tests.

Mandel and five codefendants are scheduled to go on trial April 13 in Baltimore on a 22-count federal indictment charging them with a pattern of political corruption. The case, originally scheduled to go to trial May 3, 1976, has been marked by a bizarre series of delays and occurrences, including a mistrial declared last December after two tampering incidents.

The governor is the second defendant to develop health problems in the case. Last September, the trial of Irvin Kovens, a millionaire political kingmaker, was severed from that of the other defendants after he developed a heart attack.

Lt. Gov. Blair Lee III said yesterday he is not aware, of any plans for Mandel to ask for a delay in trial. Asked at a press conference if Mandel's hospitalization would affect the trial, Lee said, "I don't think so. I think they're going to hava a hard time keeping him in that hospital."

Contacted at his home in Knoxville, Tenn., U.S. District Judge Robert Love Taylor said he plans to proceed with the trial as scheduled. "I'm a straight shooter," he said. "I can't afford to be suspicious, or nonsuspicious at this point. I'll just have to meet with all the lawyers involved after I get to Maryland Monday."

Mandel has no history of health problems. The only two times that he has appeared in other than perfect health were after he strained a leg muscle playing tennis in 1972 and after he suffered lacerations in an automobile accident in Prince George's County in 1970.

The governor appeared vigorous and self-assured during appearances before two congressional committees in Washington Monday where he testified in behalf of the Appalachian Regional Commission. He is chairman of the commission. He returned to Annapolis late in the day, and at 1 a.m. signed a proclamation extending the current session of the General Assembly.

Yesterday, aides to both Lee and Mandel said the governor has appeared tired and worn the last 10 days as the state legislature winds into its final days with several key issues unresolved.

Lee said he last saw Mandel about 10 a.m. in his office. He speculated that the governor was taken to the hospital without his consent.

"I think getting him to the hospital was pretty close to being a kidnapping job by his wife and his physician," said Lee. "He never wants to go (to the doctor) . . . The man is clearly suffering from fatigue and exhaustion."

Mandle traveled to Prince George's Hospital in his chauffer-driven state limousine with his wife, Jeanne. The 635-bed hospital is located in the Prince Geoge's County community.

Lee said Mandel has not designated him as acting governor, and does not plan to do so "unless his stay in the hospital turns out to be more extended than we expect."

He rejected a suggeston that Mandel's "exhaustion" could be accompanied by a nervous breakdown," Lee said. "I've never seen a man less jittery."

Lee said Mandel, who normally sleeps only about five hours a night, has been usually tired of late. "He's had very little vacation," he said. "You had the (13-week) long trial, and whenever he had a day off from that it was some nice, restful thing like an all-day meeting of the Board of Public Works.

"And he has been working hard the last two or three weeks" as the General Assembly has wrestled with Mandel's budget and his request for a one cent on the dollar increase in the state sales tax.

Other aides generally confirmed Lee's impression that Mandel did not know he was heading for the hospital when he left Annapolis. "He didn't say where he was going," said lobbyist Ronald Schreiber. "He said he'd be back at 2 p.m."

Mandel was assigned a private room on the ninth floor of the hospital. Two Maryland State Police guards were stationed at the door and no visitors, except Mrs. Mandel, were admitted during the day, according to hospital spokesman.

He will begin a series of tests to determine the cause of motor weakness in his right side beginning Wednesday. Dr. Hookman said such weaknesses are sometimes caused by minor strokes but he had found no evidence of any such occurences.

"It's obvious the governor has been suffering from exhaustion," he added. Asked if the symptoms had anything to do with Mandel's legal problems, Hookman said, "I'm pretty certain this has nothing to do with the pending trial."

U.S. District Attorney Jervis Finney refused to comment on the development, and Mandel's lawyer, Arnold Weiner, could not be reached for comment.

In a related development, Baltimore furniture salesman Walter Weikers, 67, has begun serving a two-year sentence at the federal prison farm in Allenwood, Pa., for attempting to bribe a juror in the Mandel trial. He has a heart condition. and my be paroled at any time if it becomes more serious.

Contributing to this story was Washington Post staff writer Judith Valente.