District of Columbia law enforcement officials yesterday arrested five Washington area men who police said for eight years have been major suppliers of thousands of amphetamines sold illegally on the streets of Washington as uppers and heroin boosters.

The arrests came after police staged a phony cut-rate sale of the pills -- formally known as Preludin but called "Bam" on the streets -- in a room at the Master Host Inn Hotel on Bladensburg Road NE.

There, undercover officers displayed 22,000 of the pink diet pills, borrowed from their Connecticut manufacturer, and sold $17,000 worth of pills to one of the five men, police said. Another waited outside in a red Cadillac equipped with a telephone and television, according to police.

Both were arrested at the hotel and the others were later arrested at various locations in Washington and Maryland, climaxing a nine-month investigation by the police in cooperation with the U.S. Attorney's office and the U.S. Drug Enforcement Administration.

Police said federal warrants had been issued for three persons, two of whom acted as lieutenants for the major distributors. Eight other warrants are outstanding for persons in Philadelphia who allegedly supplied drugs to the distributors.

The phony sale at the hotel room was arranged, police said, in an effort to get all five men into a central location by offering them pills at about two-thirds the usual price charged illegal distributors. Law enforcement officials said the sale was videotapped.

Charged with distribution of a controlled substance were Joseph Lester Brown, 41, of 2629 11th St. NW; Clarence Watts Jr., 38, of 1747 11th St. NW; Marvin Lee Cobb, 30, of 1212 Oronoco St., Alexandria; Ronald Hinton, 36, of 6308 45th Pl., Riverdale.

Police charged Thomas Leroy Watts, 37, of 5611 61st Pl., Riverdale, who police said had purchased the pills in the hotel room, with possession with intent to distribute a controlled substance.

Also arrested yesterday but not identified by police as a suspected major distributor were Darna Denise Scott, 21, of 1120 Kennbec Dr., Oxon Hill, who was charged with aiding and abetting a person to distribute a controlled substance, and Wanda Gerald, who gave her age as about 26, of 5611 61st Pl., Riverdale, and who was charged with distribution. a

Preludin use has increased in the Washington area at about the same fast rate as heroin use, according to law enforcement officials. The pills sell for about $10 to $12 each. Heroin users melt down the contents of the capsules and inject it, either alone or with heroin to speed up the effect of the heroin.

Police lured the drug dealers to the hotel by offering them the pills at a discount price of $3, about $2 below the normal price an illegal wholesaler would charge, according to Det. Johnny Mathis of the 3rd District drug enforcement unit, which handled the case.

Assistant U.S. Attorney George J. Terwilliger III traveled to Ridgefield, Conn. last week to the corporate offices of Boehringer Ingelheim Ltd., the only producer of Preludin in the United States and asked the company to supply the pills needed for yesterday's sting and received full cooperation from company officials.

Two years ago, this company voluntarily cut off the wholesaling of Preludin in Washington because so much of the drug was being diverted to the illegal market, law enforcement sources said.

Since then, most of the major local distributors have been getting the drug illegally from other cities on the East Coast, especially Philadelphia, where the illegal distributors were dealing directly with pharmacists and physicians, according to police.

up until about two years ago, the most common way for the dealers to get supplies of Preludin was to recruit fat women off the streets of Washington and pay them about $25 to have doctors here and in other cities fill out prescriptions for them.

"They don't have to round up the fat people any more," Mathis said yesterday.

Police said the five major dealers arrested knew each other but usually worked independently, each making sales of more than $500,000 each year. The pills were transported here by car or train and sold by runners -- about eight to 10 of whom were employed by each distributor, police said.

"As far as this particular pill is concerned, I think [yesterday's arrests] will make a significant impact on the sale of bam in this city," said Lt. Ronald Harvey of the 3rd District police.

The U.S. Attorney's office has been conducting a continuing investigation of doctors and druggists here who divert drugs into the illegal market by selling prescriptions. Yesterday's raid, however, was aimed at the wholesalers who are keeping the flow of Preludin plentiful on the streets despite the crackdown on local doctors and pharmacists.