Dr. Laura -- Serial Quitter

8/18/2010 10:30 AM PDT

Dr. Laura Quits -- Serial Quitter... Find Out Why

This isn't the first time Dr. Laura has taken her marbles and gone home after getting mad ... TMZ has learned she did the same thing on the boob tube.

Dr. Laura -- now famous for repeatedly hurling the "N" word on the radio show she is now quitting  -- pulled the same stunt in 1999 when CBS TV offered her a talk show.  Dr. Laura had a bunch of strings she attached to the deal -- most interesting ... that CBS muzzle Howard Stern so he wouldn't talk crap on her.

CBS refused to make the concession, so Dr. Laura huffed out of there and instead did a disastrous show at Paramount -- where she bashed gays.

Oh yeah, one more ironic twist ... Dr. Laura misguidedly said on Larry King last night that she was quitting so she could exercise her First Amendment rights ... something she clearly wanted to deny Howard Stern.
That thin skin isn't just the work of a good spa. 

UPDATE: Howard talked about this story on today's show ... click here to hear it.