Montgomery County Executive James P. Gleason won state support yesterday in his campaign to hold hostage $328 million in regional Metro construction money in return for a federal guarantee that a subway line will be built through Wheaton.

After meeting yesterday afternoon with Maryland Transportation Secretary Hermann K. Intemann. Gleason said Intemann had agreed not go sign for 60 days a contract releasing the money. A representative of Intemann's office confirmed the agreement.

At the same time, Gleason said he will release immediately $1.7 million in operating money for the Metro bus and rail system. That means Metro will have enough money to finish the first quarter of the fiscal year. It also means Gleason has avoided a confrontation with the County Council, which had ordered him to pay the subsidy.

Gleason had told Intemann earlier that he would not endorse Intemann's signing of the construction contract until he receives assurances from the U.S. government that the Silver Spring subway line will be extended on Georgia Avenue through Wheaton to Glenmont. Gleason also had withheld Montgomery County's operating subsidy for the same reason.

Intemann's signature is the last one needed. Others required are those of U.S. Transportation Secretary Brock Adams, a representative of the District of Columbia and Metro general manager Theodore Lutz. All have signed.

Without the contract, most Metro construction work will have to cease, Metro officials have said. Metro has delayed advertising for bids for construction of the King Street Station in Alexandria and has delayed opening nids for construction of the Tenley Circle Station in the District. Thus Maryland is holding up construction regionwide.

Intemann agreed to the 60-day delay, according to officials, because at the end of that period federal and Metro officials will have completed an engineering analysis on various cost-cutting methods of building the Glenmont line.

With that federally-imposed analysis out of the way, Gleason said, Adams can decide whether to build it. "If the Glenmont line is not built," Gleason said, "then the federal government should take over the construction of the entire system."

Gleason said he told Intemann that "if we release these funds without assurance of the Glenmont line, we will have lost our last ever with the federal government." The money for subway construction is coming from interstate highway funds once programmed to build freeways from Montgomery County into the District of Columbia.

Intemann had told a reporter earlier that he expected inflation would not increase costs unduly during a delay because of a depression in the construction business. In fact, most recent bids on Metro contracts have been under estimates.