Playboy magazine and representatives of much of the rest of the American publishing industry went to battle yesterday with the attorney general's Commission on Pornography, charging in federal court here that the commission issued a "threatening" and "coercive" letter to retailers that has ignited "a blaze of censorship spreading across the land."

More than 12,000 stores nationwide -- the majority run by major companies that received the letter last February -- have stopped selling Playboy, Playboy attorney Bruce J. Ennis charged in U.S. District Court. And the effects are snowballing, according to publishing associations that have joined Playboy's side, forcing such "prominent magazines" as American Photographer, Texas Monthly and Cosmopolitan off the stands in various cities.

The commission, represented by the Justice Department, countered that the letter "did not intimidate, much less censor," distributors who received it, and argued that the panel's courtroom adversaries want to "neutralize" the commission's work and make the federal judge a "super-censor" in the public debate over pornography.

Playboy and others suing seek a retraction of the letter and a public statement that the commission did not intend to imply that companies could be criminally prosecuted for selling it and other "adult" magazines. Judge John Garrett Penn took the case under advisement after a hearing that lasted nearly three hours.

The case is shaping up as a major First Amendment battle between the controversial commission, which is set to issue its report next month, and much of the publishing world. The American Library Association, the American Booksellers Association, groups representing magazine distributors and the Magazine Publishers Assocation, which represents the nation's leading magazines, have joined Playboy in the fight.

The dispute was set off last year when a Mississippi minister who heads the National Federation for Decency testified at a commission hearing that "many of the major players in the game of pornography are well-known household names" and then characterized Playboy and Penthouse as "porn magazinzes."

The Rev. Donald Wildmon then named as distributors of pornography such companies as the Southland Corp., which owns the 7-Eleven chain, People's Drug Stores, Dart Drug Stores and several other chains.

On Feb. 11, the commission sent what Justice Department attorney Robert J. Cynkar said was an "innocuous" letter seeking replies from the 23 named companies.

The letter said, in part, that the commission "received testimony alleging that your company is involved in the sale or distribution of pornography." It said the commission was seeking a response "prior to drafting its final section on identified distributors," and added, "Failure to respond will necessarily be accepted as an indication of no objection." Attached was a copy of Wildmon's testimony. However, Wildmon was not identified as the speaker.

Playboy's lawyer Ennis charged in court yesterday that since the letter went out, six major chains, including Southland's 7-Eleven stores, stopped selling Playboy and 34 other retailers who did not receive the letter have done the same. "Never before in the history of our country have so many stores stopped selling so many publications in such a short period of time," Ennis said.