Sen. James M. Inhofe (R-Okla.) vowed yesterday to hold up all presidential nominations, including President Clinton's choice of a new treasury secretary, to protest Clinton's appointment of a gay San Francisco philanthropist as ambassador to Luxembourg while the Senate was out of town.

Inhofe's action could delay action on the confirmation of Lawrence W. Summers as treasury secretary to succeed Robert E. Rubin, who plans to retire by July 4. Just the threat of a delay triggered financial tremors, with the U.S. dollar weakening against the Japanese yen shortly after Inhofe's threat. A similar jolt occurred last month when steel-state Republican senators briefly threatened to delay Summer's confirmation in a dispute over legislation to protect the steel industry.

The Oklahoma Republican was protesting Clinton's appointment of James C. Hormel to the Luxembourg post under a constitutional provision allowing temporary appointments during a congressional recess. Clinton appointed Hormel on Friday, shortly before Congress was to return from its weeklong Memorial Day recess. Hormel, whose confirmation by the Senate had been blocked by Senate Republican conservatives who criticized his advocacy of gay rights, is eligible to serve through the end of next year.

Inhofe's threat could also delay action on the pending nomination of Richard Holbrooke to be ambassador to the United Nations. Judicial nominations are already being held up in another Republican dispute with the administration.

"President Clinton has shown contempt for the Congress and the Constitution," Inhofe said in a statement before informing the Senate officially of his intentions. "He has treated the Senate confirmation process as little more than a nuisance which he can circumvent whenever he wants to impose his will on the country."

By longstanding custom, any senator can block a nomination or bill by placing a "hold" on it, signaling an intention to delay action by filibuster. Such holds are normally honored--at least for a while--by Senate leaders, although there is no rule requiring it.

Majority Leader Trent Lott (R-Miss.), who also opposed Hormel's nomination, condemned the recess appointment as a "subversion of the confirmation process" and said Inhofe has a right to do what he is doing. But, "as far as doing it indefinitely, that would not be my inclination," Lott said. Lott added that he intends to work with the administration to "keep moving nominations forward."

Minority Leader Thomas A. Daschle (D-S.D.) said Democrats will "find ways to register our protest" if Republicans embrace Inhofe's tactics.

In his remarks to the Senate, Inhofe said he is following a precedent set by Sen. Robert C. Byrd (D-W.Va.), who, as minority leader in 1985, placed holds on President Ronald Reagan's nominations to protest recess appointments. Inhofe said Byrd kept the holds in place until Reagan agreed to refrain from further recess appointments; the Oklahoma Republican demanded a similar pledge from Clinton.

But the White House appeared to be holding firm. "It's hard to think that the Senate would allow itself to be blocked from fulfilling its constitutional responsibility because one member is upset" about one appointment, said presidential spokesman Barry Toiv.

Toiv said Clinton has been restrained in his use of recess appointments, having made 57 over 6 1/2 years, compared with 239 for Reagan over eight years and 78 for President George Bush over four years.

CAPTION: Sen. James M. Inhofe is critical of appointee's advocacy of gay rights.