Sen. John P. East (R-N.C.) announced yesterday that he will not seek reelection next year because of poor health. He is the second Republican senator in less than a month to announce retirement.

The announcement, though not unexpected, will make it marginally more difficult for Republicans to retain their Senate majority after 1986, campaign strategists for both parties said yesterday. The GOP currently holds a 53-to-47 edge in the chamber, but must defend 22 of the 34 seats up for election next year.

East, 54, who has been recuperating at his home in Greenville from a case of hypothyroidism that required a lengthy hospital stay this spring, announced his support yesterday of David Funderburk, a Campbell College (N.C.) government professor who recently completed a stint as U.S. ambassador to Romania. Funderburk created a stir when he resigned as ambassador with a blast at senior administration officials for not taking a tough enough stance against the Bucharest government.

Funderburk, 41, also received the endorsement yesterday of the National Congressional Club, the powerful North Carolina-based New Right fund-raising and political machine built by Sen. Jesse Helms (R-N.C.). Six years ago, the club plucked another college professor from political obscurity into the Senate; it was John East.

Funderburk's path to the Senate may be bumpier. Rep. James T. Broyhill (R-N.C.), a pillar of the GOP's moderate wing, annnounced yesterday that he would spend the next few weeks actively considering whether to seek the Senate nomination. Just two weeks ago, he had issued an all-but-Shermanesque statement of lack of interest.

A Broyhill-Funderburk primary conceivably could break open a rift that has existed in the state for more than a decade between the mainstream Republicans of the Piedmont, who stress fiscal conservatism, and the New Right Republicans, who place more emphasis on social issues and anti-communism.

Unlike Sen. Paul Laxalt (R-Nev.), who had been considered a shoo-in for reelection until he announced last month that he would not run, East was thought to be one of the party's most vulnerable incumbents because of his poor health and low visibility.

A polio victim since age 24, East built a one-term voting record that made him one of the most conservative senators ("Helms on wheels," affectionate colleagues dubbed him). He concentrated on the abortion, busing and school prayer issues.

In a statement read in Raleigh by an aide, East said his interest in the "conservative cause remains undiminished and unabated," and added he would serve out his term.

Whatever East's potential liabilities, Democrats in the state were happy not to have to test them next year. "We're elated we are going to be entering a Senate race without having to face an incumbent," said state Democratic Chairman Wade Smith.

North Carolina Democrats received a disappointment of their own last week when former governor James Hunt (D), defeated by Helms in 1984, announced that he would not run for the Senate again in 1986.

Since then a half-dozen Democratic hopefuls have emerged. Party officials say the most active so far has been former governor Terry Sanford, recently retired president of Duke University.

R.E. Carter Wrenn, executive director of the Congressional Club, said he expected to raise $5 million to $10 million on behalf of Funderburk. Wrenn also said that Broyhill did not pass muster as a bona fide conservative because of his votes against aid for the contras in Nicaragua and in favor of the House budget resolution.

In another Senate political development, Sen. Gary Hart (D-Colo.) said yesterday he is in "no rush" to decide whether to seek reelection next year or bypass the race to concentrate on running for the presidency in 1988. "I want to wait and see what the situation is," said Hart, who did not lay down a timetable for making his decision.