Loret M. Ruppe, at the age of 45, and after raising five daughters, is starting her first paid, fulltime job -- as director of the Peace Corps.

The wife of Philip E. Ruppe, former six-term congressman from Michigan, and a longtime friend of Vice President George Bush and his wife Barbara, Ruppe will earn $55,387 per year as one of the highest ranking women in the Reagan administration.

Although she has never lived in a developing country or worked in any of the agriculture or nutrition-related fields associated with Peace Corps projects, Ruppe, who lives in Potomac, has thrown herself into the task of learning the organizational ropes -- studying maps and the Peace Corps budget, which will be reduced by $10 million this year.

"We think we can work with it," she said of the budget cut. "We'll reach out to the private sector and try to get more help. We realize that no volunteers can go overseas if the economy is in a shambles."

Her foreign experience comes by proxy, she said, through letters from a cousin in South Korea and through a visit with two sisters working in Tanzania -- one with the Catholic order of Salvatorians and the other as a teacher.

As a well-liked congressman's wife who helped her husband win six elections and cochaired the Reagan-Bush campaign in Michigan, she has plenty of political savvy.

"A lot of people have called her one of Reagan's best appointments," said Jacqueline King, Peace Corps press secretary. "She's the new person on the block in a new administration, and that's not a comfortable position for anybody. But she has come and she just fits in. She's a very down-to-earth woman."

Although Ruppe has yet to be confirmed by the Senate Foreign Affairs Committee, she was warmly received by the House Foreign Affairs Committee before a hearing on the Peace Corps budget, and has been going to the Peace Corps headquarters every day since her nomination. She calls herself a "student volunteer" there, and has been busy learning about the organization, which currently has 5,400 volunteer members stationed in 63 countries.

"I didn't even know when the fiscal year began," she says, and with the same disarming frankness she talks about how she started with the Reagan-Bush campaign in Michigan and ended up as Peace Corps director.

Sitting in her Potomac living room with George Washington, her white schnauzer, she recalled how her husband, after deciding not to run for a seventh term in the House in 1978, suggested they get involved in the presidential campaign. On the reputation of her success in organizing his congressional races, Loret Ruppe was asked to cochair the Reagan-Bush campaign in Michigan.

"Three weeks before the election George asked what I would do afterwards," recalled Ruppe. "Actually, I hadn't projected ahead. When I got back home after the election, all the newspapers said there was a mad scramble for jobs, and I thought, how stupid of me not to have asked, when I had the vice president's ear."

She tried to call Bush in Texas, but the vice president was in California. He returned her call later, and this time she didn't hesitate.

"'I'd like a job in the new administration,' I told him. He said that he wanted me to work on the inauguration first, and then we would see."

Ruppe planned Bush's inaugural reception and meanwhile, there were discussions at the White House about her placement. Volunteer work of some kind was suggested, and then the idea of Peace Corps work came up. "My husband was very influential. He thought with my background in volunteer work and my travel overseas that it would be ideal." Philip Ruppe is now a lobbyist for AMAX, Inc., a mining firm headquartered in Greenwich,Conn.

Former Peace Corps director Richard Celeste said he didn't think having lived overseas was essential for a director. "Qualities of intellect, determination and enthusiasm are needed to make something like the Peace Corps work, and I sense those qualities in abundance in Mrs. Ruppe."

Rep. Clement Zablocki (D-Wisc.), chairman of the House Foreign Affairs Committee, told Ruppe that if his committee had the confirmation power, she would be confirmed unanimously.

Rep. William S. Broomfield (R-Mich.) noted her work in six successful campaigns for her husband and said her "lifetime concern for others . . . personifies what the Peace Corps is all about."

"I'm meeting fascinating people and have experiences that I would never have had," said Ruppe, who came to Washington in 1966 from Houghton, a village of about 6,000 in northern Michigan that is farther from Detroit than Washington is.

Ruppe will direct the agency during its 20th anniversary year and also oversee a reduction of Peace Corps services. Reagan's $10 million cut in the budget (currently $105 million) will necessitate the withdrawal of volunteers from four countries and reduce the Washington staff by 35 persons, to 162. The countries that will lose Peace Corps volunteers have not yet been chosen.

"I think you can probably live with a $95 million budget," said Broomfield in the committee hearing. "It may not be easy, but it would offset some of the criticisms (of the agency)."

Broomfield was referring to published reports that some Peace Corps workers were living in luxurious apartments in the poor countries to which they were assigned.

Ruppe says he will use her knowledge of Washington political circles to drum up support for the agency.

"As spokesperson for the Peace Corps, I want to let people know how interested President Reagan is in the Peace Corps, and that volunteers are more important than ever in a time of budget cutting," said Ruppe.

"For some reason, the Peace Corps has lost its identity in the last 10 years. We want to turn that around in the '80s. So many people don't realize the Peace Corps is a strong, viable organization."

In the 20 years since it was founded by President John F. Kennedy, the agency has undergone several structural changes. In 1971, President Nixon placed it under the auspices of ACTION, which oversees government volunteer programs. In 1979, Jimmy Carter issued an executive order declaring the Peace Corps autonomous within ACTION and shifting some of the administrative responsibilities back to the Peace Corps director.

Acting director William Sykes told the House committee the agency faces a shortage of skilled volunteers to meet the needs of developing countries, especially the black and Hispanic volunteers who frequently are requested by African and Latin American nations.

In order to attract such volunteers, the agency is studying the idea of reducing tours of duty from two years to one, and of getting colleges to offer credit for Peace Corps work, Sykes said.