BALTIMORE, JULY 17 -- Were government doctors responsible for the 1986 suicide of Sen. John P. East (R-N.C.) because their delayed diagnosis of a thyroid ailment triggered an "irresistible impulse" by East to kill himself?

Or was suicide a "conscious and voluntary" act by East, despondent over senatorial obligations unrelated to his health?

Attorneys for U.S. Navy doctors and East's widow, Priscilla, wrangled for five hours today over those questions in closing arguments in Priscilla East's $3.5 million medical malpractice suit in federal court here.

U.S. District Judge Walter E. Black Jr., who heard testimony in the eight-week-long nonjury trial earlier this year, did not indicate when he would rule. In cases of this complexity, judges typically issue written rulings after several weeks.

The case, thought to be the first wrongful-death action against the government by a U.S. senator's survivor, is being closely watched by medical administrators, especially in the Navy, which is responsible for health care at Bethesda Naval Hospital and the Office of the Attending Physician at the Capitol.

John East, a conservative elected to the Senate in 1980 with the blessing of Sen. Jesse Helms (R-N.C.), ended his life June 29, 1986, by filling the garage at his home in Greenville, N.C., with carbon monoxide. He left a note blaming naval doctors, "who ruined my health." He was 55.

Priscilla East sued the government in 1987, claiming that naval doctors had ignored early symptoms of hypothyroidism, a condition in which the thyroid gland fails to produce hormones to maintain the body's proper metabolism.

She contended the symptoms -- fatigue, depression and abnormal levels of cholesterol and liver enzymes -- were apparent in 1983 and 1984 but that doctors did nothing until April 1985, when East was rushed to Bethesda Naval Hospital in an advanced psychotic state of hypothyroidism called myxedema madness. He became delusional and attempted suicide by ramming a chair leg down his throat, family attorneys said. Gradually his condition was stabilized, and his thyroid condition corrected with synthetic hormones.

Even though corrected, family attorney James A. Hourihan said today, East's thyroid-induced depression became "autonomous," triggering an "irresistible impulse" that eventually caused him to kill himself.

If doctors had detected and treated the thyroid condition in its early stages, Hourihan argued, East never would have developed the madness that led to his death.

Assistant U.S. Attorneys Ira L. Oring and Susan M. Ringler countered that the early symptoms cited by Hourihan are not indicative of hypothyroidism. Also, they said, once East was treated in April 1985, his thyroid would not be the cause of any continuing depression.

Rather, Oring said, East's depression was caused by external factors, especially his unhappiness in the Senate. Oring retraced trial testimony by psychiatrists that East, a former college professor, was unchallenged by his Senate duties.

While East didn't like political life, Oring said, "he felt compelled to stay in the Senate" because Helms and others in the conservative Congressional Club had helped him get there, "and he didn't want to be seen as a quitter."

Oring also said Priscilla East's testimony that she watched her husband deteriorate physically and mentally from 1983 to 1986 was contradicted by medical records and her private diaries. " 'He looks great . . . . John is feeling so well,' " Oring read from diary entries in 1983-84.

While Priscilla East testified that her husband was becoming depressed, fatigued and disoriented, Oring said, her diaries contained numerous references to dinners, parties and receptions that the two of them attended.

Even in the final months before he died, Oring said, East was active in Congress, appeared on an hour-long television interview, agreed to write chapters for a book and announced his decision not to seek reelection and to return to academia.