Marriott Corp. lost its second-ranking operating executive to International Telephone & Telegraph Corp. yesterday.

ITT said G. Michael Hostage, 45, executive vice president of Marriott, will take over as president and chief executive of its continental baking Co. subsidiary on Feb. 1, succeeding M. Cabell Woodward Jr., who has been named executive vice president and chief financial officer of the parent conglomerate, ITT.

Hostage reportedly informed Marriott President J. W. Marriott Jr. of the decision about two weeks ago. The Washington lodging, restaurant and food service company announced several top management changes of its own yesterday-parceling out Hostage's jobs to several key executives, but not replacing him with one individual.

The departure of Hostage from the Marriott executive suite is a key loss. He joined the local company in 1963 after nine years in sales and marketing for Procter & Gamble Co., and advanced rapidly in the Marriott organization-organizing its food service management division and subsequently taking over at various points the expanding restaurant, amusement park, hotel and food manufacturing divisions.

Hostage became president of the restaurant group in 1970 and executive vice president of the company in 1976, with overall responsibility for the company's consumer-based businesses. He earned about $171,000 in the most recent fiscal year, second only to company president Marriott.

Hostage is known by associates as an ambitious person "who wants to move ahead." One source said yesterday that Hostage thought he had "gone as far as he could go" in the Marriott organization because president Marriott is about the same age.

There were no indications of major policy conflicts behind Hostage's move. Rather, Hostage's new job with Continental Baking "is an pretty good platform from which to move into senior management at ITT," one knowledgeable person said.

ITT's baking subsidiary is one of the largest in the nation, producing more than 1.1 billion loaves of bread a year with sales of about $1.5 billion a year, under the "Wonder" and "Hostess" brand names. The ITT unit also is engaged in frozen and specialty foods through its Morton Frozen Foods, C&C Cola and Virginia-based Gwaltney divisions.

Separately, Marriott announced four promotions-most of which were being planned before Hostage's surprise decision, a spokeswoman said. Changes at the company, effective Jan. 1:

Richard E. Marriott, like President J. W. Marriott, a son of company founder and chairman J. Willard Marriott, becomes corporated group vice president. In addition to the 500-unit restaurant operations he has supervised for several years, Richard Marriott will assume control of the amusement parks from Hostage.

Gary Wilson will become senior vice president for finance and development. The new chief financial officer previously was vice president and treasurer.

Francis Cash, formerly vice president and controller, will become a senior vice president. He continues as chief accounting officer and will add two of Hostage's former responsibilities, food production and distribution here and corporate procurement, as well as tax and information systems.

Robert E. Koehler, formerly senior vice president for finance will assume the new post of senior vice president for corporate administration.

James Durbin, the president of Marriott hotels who formerly reported to Hostage, now will report directly to president Marriott.

Although Hostage has not been replaced, Wall Street analysts said yesterday they expect the company to pick a successor in one or two years, after current executives have had more experience in their positions and their performance can be judged.

Chief officers are departing from three area financial institutions-two of them on friendly terms and one because of a policy dispute. In each case, no successor has been named. The details:

Government Services Savings & Loan Inc. of Bethesda-Arthur J. Phelan Jr. has resigned effective Dec. 31 as chairman and a director, following "differences of opinion . . .regarding certain operating policies" and a desire to pursue other business interests. He joined the S&L in 1964 and became president in 1971 and chairman in 1973.

United Saving & Loan, Arlington-Charles Nevaiser, chairman since 1976, is resigning to devote more time to personal business and family after presiding over a period of rapid expansion as assets doubled to $67 million and earnings doubled, too. "I leave with the satisfaction of accomplishment being evcen greater," Neviaser said.

D.C. National Bank-Irving Rudd, an orginal organizer of D.C. National who became executive vice president in 1963 and president in 1974, is stepping down as president and chief executive to retire to Florida. He will remain a director.

The National Broadcasting Co. has named a new general manager for WKYS, its FM station here. Raymond Yorke, the new executive, previously was manager of an FM station in Tampa.