LOS ANGELES — Comedian and actor Garry Shandling, who made his name as a frequent guest host on late-night television and for parodying himself as star of the pioneering cable TV comedy series, “The Larry Sanders Show,” died on Thursday at age 66.

Shandling, who began his showbiz career as a writer for TV sitcoms such as “Welcome Back, Kotter” and “Sanford and Son,” was transported from his Los Angeles home to an area hospital where he was pronounced dead, police and coroner’s officials said.

The performer, who had been relatively healthy, called emergency 911 for help himself and suffered an apparent heart attack, his publicist, Alan Nierob, told Reuters. He added that Shandling had no history of heart disease, “zero.”

Lieutenant Brian Elias of the Los Angeles County medical examiner’s office confirmed the entertainer apparently died of natural causes. “There’s nothing suspicious about the case, whatsoever,” Elias said.

Tributes to the innovative performer, known for a somewhat socially awkward, nervous comic persona, immediately poured in from the comedy world at news of his death.

Fellow comedian Kathy Griffin, who just a few days ago posted a photo of herself with Shandling and actor Bob Odenkirk on social media, said on Twitter: “Sunday, my longtime friend Garry Shandling was here, making every1 laugh. I loved him. I’ll miss our talks the most.”

Retired late-night television host David Letterman, whose NBC show was offered to Shandling, and declined, when Letterman moved to CBS in 1993, said in statement: “Stunned and sad about Garry. Great stand up, great writer. Television shows are classics.”

Other comedy luminaries paying tribute to Shandling included Steve Martin, Ricky Gervais, Amy Shumer, Jimmy Kimmel and John Cleese.

Although he was a frequent, longtime fixture on broadcast television talk-show circuit, Shandling made his biggest splash on cable television in its early days.

He created and starred on the Showtime network’s “It’s Garry Shandling’s Show” in the mid-1980s, a program that defied convention by calling attention to the conceit of the show itself, going so far as to integrate the studio audience and the set into the action. It ran for 72 episodes, through 1990.

But Shandling went on to greater commercial and critical acclaim with another show-within-a-show series, “The Larry Sanders Show,” which ran from 1992 to 1998 on HBO.

It starred Shandling as a satirically exaggerated version of himself hosting a fictional late-night TV talk show, drawing on his real-life experiences as a stand-up comic and regular guest host for NBC’s “The Tonight Show starring Johnny Carson.”

Shandling won an Emmy in 1998 for his writing on the series finale.

Co-starring Jeffrey Tambor and Rip Torn, “Larry Sanders” was one of HBO’s first big successes and is seen as a forerunner for parody-heavy comedy hits that came after it, including “”Entourage,” “30 Rock” and “Curb Your Enthusiasm.”

HBO said in a statement that Shandling’s show “ushered in the modern period of original programming” at the pay-cable network.

A Chicago native, Shandling grew up in a Jewish family in Tucson, Arizona, before moving in the 1970s to Los Angeles, where he first worked in advertising and later became a script writer for TV sitcoms and developed his own stand-up comedy act.