FILM: LORI SINGER IN 'SUMMER HEAT'  

By Judy Klemesrud  Published: July 19, 1985

LORI SINGER, who for a while seemed to be playing every teen-age role that wasn't offered to Molly Ringwald or Ally Sheedy, has finally grown up. In fact, it will be hard to think of her as a teen-ager again after her appearance as Maddy, the sexy, intense, career-driven Government agent in the Stan Dragoti comedy ''The Man With One Red Shoe."

''I love it,'' Miss Singer, who is actually 23 years old, said in an interview. ''After 'Fame' and 'Footloose,' I kept getting offered all these teen parts. It's really nice to play an adult for a change.''

In the film, Maddy falls in love with a violinist (played by Tom Hanks), who unknowingly becomes involved in a bizarre conspiracy in which he is bugged, shadowed and almost wiped out by a band of Government agents.

Miss Singer said she had prepared for the part by talking with two female C.I.A. agents, and by copying the mannerisms of a New York management consultant named Susan Engel, who is a friend. ''Susan really inspired me,'' Miss Singer said. ''I got Maddy's intensity and sharpness and speed from her.''

Miss Singer, who is 5 feet 10 inches tall with long blond hair, originally planned to be a cellist. She is a graduate of Juilliard, where she was first cellist in the school's orchestra, and she has played professionally with a number of groups. Her father, Jacques Singer, was a symphony orchestra conductor, and her mother, Leslie, is a concert pianist. Her twin brother, Gregory, is a violinist.

But, like her older brother, Marc Singer, star of the television series ''V,'' she chose acting. ''In a world where such terrible things are happening,'' she said, ''it's just so fantastic to become someone else.''

She was first noticed in the role of the shy cellist in the television series ''Fame.'' In the film ''Footloose,'' she played the daughter of a preacher who longs to break out of her strict small-town environment, and in ''The Falcon and the Snowman'' she played Timothy Hutton's girlfriend.

Miss Singer lives in New York with her husband, Richard Emery, a civil liberties lawyer. She said she was not worried that her part as the secret agent would cause her to be typecast in sexy roles, because she has just finished an Alan Rudolph film called ''Trouble in Mind,'' with Kris Kristofferson and Keith Carradine, in which her character is very different from Maddy.

''She's an innocent, backwoods character,'' she said.