LOS ANGELES (Reuters) - Playboy founder Hugh Hefner changed American pop culture, one centerfold at a time.

Hugh Hefner, one of the stars of the comedy film "The House Bunny", poses at the film's premiere in Los Angeles August 20, 2008. REUTERS/Fred Prouser

With his Playboy Enterprises Inc in talks to be sold for about $300 million, the 83 year-old Hefner will be giving up control over the iconic adult entertainment empire he founded that was instrumental in shaping society’s opinions on nudity, sex and free speech.

With $600, Hefner in 1953 published the first Playboy magazine with a partially nude photo of Marilyn Monroe at its center. The magazine would become not only one of the most successful publications ever, but also a brand that led many Americans to think about sex in a more carefree way.

“Hef” turned Playboy and its bunny head logo into a symbol for a lifestyle he embodied as bachelor extraordinaire, living in a mansion surrounded by wealth and beautiful women.

“This guy was one of the major players in the transformation of American culture in the second half of the 20th century and not just because he had a magazine with naked women in it,” said Robert Thompson, a professor of pop culture at Syracuse University.

In 1972, Playboy had a worldwide circulation of 7 million, but that has been in decline ever since, as the liberalization of sexual attitudes Hefner promoted became more mainstream -- and more competitive.

But even as it grew ever more popular, the magazine created rivals such as Penthouse and Hustler. In the 1980s, adult videos grew into a major business and by the late 1990s, the rise of the Internet and free pornography on the Web became Playboy’s greatest rival for an audience.

REALITY STAR

Hefner remains in the limelight today, showing up at media events with numerous girlfriends by his side. He enjoyed a role in reality television show “The Girls Next Door” on cable network E! and his dating life and break-up with model Holly Madison made him a staple of celebrity magazines.

Hefner has said that growing up during the depression he always looked back wistfully to the 1920s age of flappers as an era of freedom he had missed.

He has described himself as having liberated America from its Puritan past and experts agree he did make sexual images and content more acceptable to Americans.

But Playboy magazine also showed men how to enjoy stylish clothing, good liquor, sports cars and other luxuries, and became a standard bearer for that lifestyle -- real or imagined.

“All that kind of stuff just piled up issue after issue -- promoting that idea of consumer abundance as being synonymous with the good life in this country -- and Hefner is very important in promoting that idea,” said Steven Watts, author of “Mr. Playboy: Hugh Hefner and the American Dream.”

But as Playboy’s fortunes waned, some of the symbols of wealth that surrounded Hefner became harder for him to hang on to.

In the early 1980s, he had to give up a private jet plane with a bedroom, a miniature disco and a kitchen, Watts said.

Through the decades and despite the loss of business, Hefner continued to live the good life and made sure everyone knew it.

“Hefner really tries to completely disengage the notion of guilt and sin from having a good time and, the last couple of generations, that has pretty much prevailed,” said Thompson, the Syracuse professor. “Certainly, when I talk to my students, I don’t get a sense they’re feeling guilty about the good deal of fun they’re having.”