Teen-agers are interested in music; a lot of music is written about what interests teen-agers.

"It's a cycle," said Susan Lechner, co-producer of WJLA-TV's "Pick Up the Beat," "and we put ourselves right in the middle of that cycle."

"Music is one of the most powerful ways of reaching out," added the show's other producer, Susan Altman of Altman Productions. "We tackle difficult subjects affecting young people, and try music and videos to offer ways of dealing with these problems."

Working with these basic ideas, the half-hour program, which airs at noon on Saturdays, has dealt with topics such as teen suicide, teen pregnancy, runaway children, drunk driving, crime, personal conflict and the military.

The show made its debut about 15 months ago. In its first year host Erik King won a local Emmy and so did cinematographer Beverly Bryan. This year the show has been nominated for three more Emmys, King for a second, as well as director Bill Melton. The D.C. American Legion Auxiliary nominated "Pick Up The Beat" for a national award as "the best local television program in the interest of youth." The winner is expected to be announced in August.

One or two of the program's videos each week are produced locally, using area youngsters. When appropriate, some commercial videos are added. But usually the rock songs that apply to the show's topics have never been made into videos, leaving that task open to the imagination of the program's producers and the skills of its teen-agers.

The show has become so popular that students from virtually every high school in the area have auditioned for roles. Even teachers, parents and young children have participated.

*Lechner noted that the size of the auditions has increased significantly. This year, between 500 and 600 students applied to work on the show. From this group the producers select teens for monthly auditions. There are a lot of "great, talented young people in the area," Lechner added.

Between videos, King chats with guests who have something to say about that week's theme. Guidance counselors and local agencies help provide the experts, and youngsters often provide poignant views of their own.

Altman Productions has been responsible for "It's Academic," which recently completed its 25th year at WRC-TV, as well as "It's Elementary," once on both WJLA and WBAL but now on WBAL only. Altman also does ''Heads Up," which won the Golden Dial Award in Baltimore.

Two years ago Altman and Lechner sat down with Jim Griffin, WJLA's director of broadcasting, and came up with the "Pick Up the Beat" format. "No one has ever used rock videos for social value before," Lechner noted.

King, who was once a regular on "In Our Lives" on WDVM, was chosen to host the show because of his easy manner and his way with the younger set. He has a part in the upcoming movie "Street Smart" with Christopher Reeve, and played a militant in the film "Kennedy." He's also busy putting together a one-hour version of "Pick Up the Beat" for this fall.

A graduate of the Duke Ellington School of Performing Arts, King has a B.A. degree in theater from Towson State. He was in the off-Broadway productions of "Wasted" and "Balm in Gilead," in "Streamers" at the Kennedy Center, Arena Stage's "Five on the Black Hand Side" and the national touring company of "Baltimore Voices." He has also appeared on ABC network shows "Ryan's Hope," "One Life to Live," "Spenser: For Hire" and "Children of Times Square."

"We have an awful lot of fun doing this," said Lechner. "We often shoot a video in four or five hours at different locations around town. People are being more responsive and we're getting more and more excited. The directors, the cinematographers and the staff are having a wonderful time with this show. So are the teen-agers."