What does Mieke Tunney's dog have to do with the sex life of an Arizona editor? tin April of last year William and Kay Woestendiek - he's the executive editor of the Arizona Daily Star in Tucson - attneded a newspaper editor's convention in Washington. Walking in the Kalorama area one Sunday afternoon, the Woestendieks spotted a German short-haired pointer bounding down the sidewalk. The dog ran into Kay Woestendiek, knocking her over, sending her to a hospital emergency room and, according to the Woestendieks, ending their love life for several months.

Just how badly she was injured is the subject of a lawsuit filed in Washington's Superior Court against the dog's owner, Mieke Tunney, ex-wife of the former California senator.

"She was just bruised," says Mieke Tunney. "Without a doubt, they must have heard cash register bells ringing, and they must assume I'm rich," she adds, hastening to mention she's not rich. She spends her days raising her three children and does not hold a job.

"If that were the case, we'd be suing for a lot of money," answers Woestendiek, who is seeking $6,632.45 in damages. That includes medical expenses, airplane and hotel charges for the week the Woestendieks allege Mrs. Woestendiek had to lie on her back in pain in her hotel room, and $1,500 for her "husband's loss of sexual relations, anxiety and aggravation."

The Woestendieks' Washington lawyer, Gerald Stoltz, says he's set to begin discovery.

Footnote: April in Washington seems to be traditionally a troublesome month for the Woestendieks. They met when both of them worked for the Houston Post in the late '60s, and then moved to Washington. The Woestendieks became a cause celebre when, in April of 1970, he was fired from his job as editor of a news program at WETA-TV when she became Martha Mitchell's press secretary. At least one congressman called for an investigation to determine whether Democratic pressure - fueled by displeasure with Mrs. Woestendiek's job - led to William Woestendiek's firing. CAPTION: Picture, Mieke Tunney, AP - 1971 Photo