Maria Shriver has glided nimbly into the host role formerly played by Bryant Gumbel on the NBC News program "Main Street," as today's edition of the monthly magazine, at 4 on Channel 4, attests.

Nevertheless, the program is given to a certain stuffy stiffness that may alienate the young audience at which it is aimed. Adolescents who take hyperkinetic commercials, MTV and David Letterman in stride are likely to find "Main Street" groaningly poky. The studio segments, featuring a group of young "Main Street Friends," have about as much intimate naturalism as a board of directors meeting at General Electric.

Even so, two of the "friends," young ladies named Alyssa and Leigh, prove assured and unaffected communicators when they get a chance to speak, commenting on the various news pieces strung together for the show.

The first segment at least tries to be hip. It's a quickie bio of the pop star Madonna, who is as charismatic as ever. But her sound bites are intercut with remarks from her older brother ("She was different, all the way down the line") and clips from her music videos, and a too-regular rhythm is quickly established. It achieves a metronomic monotony.

The brother, incidentally, says he has to ignore lewd remarks uttered in bars when one of Madonna's sexy productions appears on a TV screen. "What am I gonna do," he asks rhetorically, "go beat up everybody?" You do get an insight, if you want one, as to why Madonna left home.

More serious reports include a look at two of the 50,000 teen-agers working American fields as underpaid migrant workers; an extremely sensitive and frank essay about the problems of living with a disabled sibling; and a lively piece by young and accomplished reporter David Sands on "shock jocks," the deejays who regale audiences with blue material.

The Federal Communications Commission made a (typically) clumsy attempt at cracking down on this form of free speech last spring, and at a protest rally glimpsed in newsreel footage, a man holds a sign that defines FCC as "Fascist Commie Creeps." My, but I got a hearty chuckle out of that one.

A student at West Potomac High School in Fairfax County reads an editorial she wrote about black students who feel that if they apply themselves too seriously to their studies, it will appear they are trying to act "white." A car goes by in the middle of her reading, but NBC News was too cheap to do a retake.

In the last segment, the boring actor Jason Bateman, star of the NBC sitcom "Valerie's Family," drops by to discuss himself, clearly a favorite subject. Shriver blank-mindedly asks him dumb show biz questions, like how was it making the transition from TV to the movies (the forthcoming "Teen Wolf Too"). Bateman says he waited until he found "the right product" to make his big-screen debut. A real sweet kid.

There are moments of tastelessness. A follow-up about a young man named Jimmy -- a hemophiliac with AIDS profiled on "Main Street" in 1985 -- is accompanied by jaunty rock music, even when it is mentioned that Jimmy died this year.

NBC is the only network producing a news magazine for kids and would like to be praised endlessly for that fact. But "Main Street" could definitely stand a touch of urban renewal.