When the impact of what his man, Roberto Duran, had done hit trainer Freddie Brown, his immediate instinct was to mutter, to no one in particular at ringside: "He quit."

A reporter reminded him of that a short time later and Brown, smiling ever so slightly, said: "Why should I say that? I gotta get paid."

The immediate reaction to Duran quitting with 16 seconds left in the eighth round Tuesday night, simply throwing up his right hand and giving back the World Boxing Council welterweight championship to Sugar Ray Leonard, is to gather every bit of stored-up bile and hurl it at Duran.

Taunt him, as Leonard did during a tasteless seventh-round humiliation so many of us quickly assumed was the primary reason Duran quit in the eighth. The appelation "Hands of Stone" no longer applies to Duran. Now it's hands of silly putty. He entered a local hospital here early this morning for tests for stomach pains -- but perhaps he should have asked for a heart transplant.

But that mood passes, though just for an instant, and J.R. Richard leaps to mind. The splendid Astro pitcher complained of unseen misery and almost no one believed him. He was called a quitter, and worse, until the doctors discovered blood clots and performed a 19-hour operation to save his life.

Roberto Duran looked awfully spry late this morning, about 12 hours after he quit with a smile on his face that fostered contempt rather than pity.Attacking a breakfast of steak and eggs with his usual primitive vigor, he seemed more a punk than a legend.

At 3:15 a.m. today, with no advance warning, Duran walked into the emergency room of Southern Baptist Hospital with one of his private doctors and several followers along. A hospital spokesman, Shep Plesants, said Duran was complaining of "stomach pans, severe stomach pains."

After being examined, Duran was taken to a room befitting his stature, the Nolty J. Theriot Memorial Suite on the fifth floor that runs $255 per day (American Plan).

"When I left the room at 7 a.m.," Pleasants said four hours later, "he and his doctor were asleep. There were two policemen guarding the suite." Shortly before noon, Duran left the hospital through a seldom-used entrance and was taken to his hotel.

Almost immediately upon arrival at the hotel, Duran went to the open-air dining area off the lobby and began eatting. He looked shame-faced when an admirer or two greeted him. Later, in an elevator, he took off his knit hat and gave it to a boy. Then he dashed off to seclusion once again.

Eating, both too much and not enough, were said to be part of what caused his announced ailment, cramps. He also complained, after the fifth round, that his left arm hurt. Heart trouble? Officially, everyone says no.

Clearly, Duran's manner of exit from the ring hit his other trainer, Ray Arcel, harder than any punch. Early this afternoon, the 83-year-old man, who had worked with 19 champions during 63 years in boxing, also quit.

"I won't work with boxing any more," he said, less than 75 feet from where Duran was hiding. "It's one of the roughest, hardest businesses. There's no one reason (for retiring). It's just too rough. I've had enough of it."

Arcel, one of the few within the Duran camp who exudes a sense of trust, also assumed that Leonard's seventh-round antics were a major reason for Duran's quitting in the eighth. What Leonard did was dance through most of an act Muhammad Ali honed. The shuffle. Dropping his guard. Leaving his chin unprotected and then jutting it out even closer to Duran's fists.

"After the round," said Leonard's manager, Angelo Dundee, "I said: 'Don't do that. You're the welterweight champion of the world. Act like it.'"

Like Dundee, Arcel thought Leonard's antics both hotdoggish and stupid. He expected Leonard to pay for it, perhaps with something close to his life.

"I thought Duran would tear him apart," Arcel said. "I never thought Roberto Duran, with his accomplishments in the ring, would quit. He isn't a quitter. He's the type of individual who would rather die in the ring than quit.

"I'm sure if he could have continued he would have. As much as I know of Duran, that's how I feel."

By his apparently final act in the ring, Duran all but destroyed a near-legendary career. It was Duran, the man with the pet lion, who created the aura of an almost mystical level of mean. His desire to project the image of maniacal intensity leaves him open to be judged all the more harshly for backing away from a fight while he was still standing and had no apparent marks.

"I know Roberto was mad that he stopped," said his business advisor, Lui Henriquez. "He was very angry that he did that. The reaction in Panama will be bad. I've gotten a million phone calls from home. We do have a lot of heroes in Panama, but he is the hero. It will be difficult for them to accept this.

"It is a small country, only 2 million people.And there's no place to hide. Especially for him."

The Louisiana State Athletic Commission was properly suspicious, though its chairman, Emile Brumeau, a man seemingly born in a foul mood, surely gave this town a purer reputation than it deserves.

"You could kill our town for six months with the fight they had tonight," he bristled shortly after announcing Duran's purse would be withheld pendng an investigation. "You saw the ending of the fight. We have an obligation."

Late yesterday, the commission met in closed session and voted to fine Duran $7,500 for an "unsatisfactory performance" against Leonard.

The air around this fight is as foul as any in memory. Greed was rampant even before the opening bell, with closed-circuit tickets as high as $50. Even as classic a show as Fight 1 in Montreal hardly justified charging nearly twice as much to watch it.

Boxing's credibility has taken a pummeling in the last year, with the Larry Holmes-Scott LeDoux fiasco followed by an over-the-hill Ali taking $8 million for throwing perhaps eight punches at Holmes. And now the Duran Disaster.

"I don't think anything could be done," Brown said of the state boxing commission investigation before the fine had been announced. "Know what I mean? He says cramps and his shoulder. They take X-rays and they don't show anything. Anything. I don't know. A fellow with all his guts. It's gonna (affect), you know." He stopped and tapped his head.

To the as-yet-unanswered why about Duran's demise, a person who usually assumes the worst about boxing is rooting for a plausible explanation, with documents supplied by neutral sources. He does not expect one.