At the networks, they believe in flaunting it even if they haven't got it. Thus does NBC tonight inaugurate the tactic of "double-pumping" some of its new fall shows, the purposes being to get a jump on the competition and to inconvenience TV critics as much as possible.

Not only are pilots for the new shows airing weeks before the season officially begins on Sept. 17, but NBC plans to rerun the pilots during the first two weeks of September. Is it too much of a good thing? No, it is just too much.

"Hull High," "Parenthood" and "Lifestories" get double-pumped tonight.

At Cordell Hull High School, shouts an announcer in an NBC promo, "students take pride in studying one thing: each other." The premiere of "Hull High," at 8 on Channel 4, unveils the first of this season's musical shows -- in this case a combination of "Fame" and "Grease" about a bunch of rockin' boppin' hip-hoppin' teens and their tedious attempts to avoid education.

The preview tape submitted by NBC was six minutes short; presumably, those six minutes will contain more musical numbers, since there were few in the rest of the show. Mostly it's just more dumb comedy about hip, cool kids.

One musical interlude occurs when a voluptuous English teacher (Nancy Valen) writes "soft and round as a peach" on the blackboard while students pantingly ogle her fanny (the female students as well as the male are transfixed by her magnificent body, or so it's made to seem).

Soon one and all have erupted into a production number that finds Teach bumping and grinding on a giant book by Longfellow. The number recalls the amiably notorious "Hot for Teacher" video by Van Halen.

Various stock types and stick figures are paraded out for perusal. A love-struck boy spots the girl of his dreams within the first few moments of the show but is discouraged when a catty girl claims the young woman is a narc. "Nobody wants drugs in the school, but we don't need a traitor to help us 'just say no,' " says the girl in a nifty example of network-mandated equivocation.

Eventually the distressed twosome unite, and what a relief, since they make such beautiful dialogue together.

"So -- will you go out with me sometime?"

"Sure."

"Yeah?"

"Yeah."

"Cool!"

Director Kenny Ortega, the choreographer, has yet to work actual wonders with the show, but a Greek chorus of omniscient rappers, wandering in and out of the plot, has promise. In the pilot, they are seen too little, whereas everyone else is seen too much.

"Parenthood," at 9 on Channel 4, is obviously based on the hit movie comedy of 1989, which just happened to make its cable TV bow Saturday night on Showtime. This will work to NBC's disadvantage, since the superior cast of the movie will be fresh in many viewers' minds.

On the other hand, the network points with pride to the fact that many of those behind the scenes on the film fill similar roles on the series, including executive producers Ron Howard, Brian Grazer, Lowell Ganz and Babaloo Mandel.

All very nice, but at an hour in length, "Parenthood" seems like a prolonged, and rather melancholy, sitcom. There are too many characters, and it's hard to keep the relationships straight. Replacing the irreplaceable Steve Martin as the father of a 10-year-old problem child -- and a man who remains something of a problem child himself -- is the capable but unexciting Ed Begley Jr.

On the premiere, the worrywart kid frets about his first day at school (there'll be lots of first days at school among this season's new family-oriented shows), the other kids bicker, and parents try to have sex only to be interrupted by one of their toddlers. Hey, there's a new one.

William Windom, as Begley's cranky dad, has the best lines. Complaining about having to share a house with his mother-in-law, he's assured by his wife that the woman only has a few years left. Scowls Windom: "She'll outlive the sun."

Others in the large cast include Jayne Atkinson, Maryedith Burrell and that grating sourpuss Ken Ober, host of MTV's super-stupid game show "Remote Control." These horrible MTV people should be tightly contained within MTV. Or within the grubby netherworld of cable, if they must venture out.

"Lifestories," at 10 on Channel 4 -- formerly "Signs of Life," formerly "Life & Death" -- is a prideful joy among NBC executives, and certainly the program brandishes as many Good Intentions as ABC's "Life Goes On" did last season.

There are obvious "positives. For one thing, many of the men who watch tonight's episode will race to their telephones tomorrow morning to schedule medical examinations they have been putting off for too long already.

The idea behind the series is to chronicle an illness not from the viewpoint of one of TV's godlike doctors, but from that of the patient. A very good idea, a very noble idea, a very promising idea. But then they went and made the first patient pretty godlike too.

As Don Chapin, who discovers he has colon cancer, Richard Masur responds in a manner that seems realistic only in haltingly measured ways. Things get so icky -- and not because of the medical details, the use of words such as "defecation" and "excrement" and "colostomy bag."

Most of the ickiness comes from Don's response to his malady, for which he undergoes an operation and subsequent chemotherapy. He's a developer, and one day after he vomits in the street, a homeless man gives him a drink of water, and Don decides to run right out and build a shelter for the homeless in the very spot where his son planned to erect a health club.

"The way home is down Hope Street," says narrator Robert Prosky, an intrusive chatterbox, with dramatic solemnity. Hope Street is where the shelter is built. The homeless are depicted the way Hollywood liberals always depict them, as dear and saintly darlings.

Earlier, Don gets to feeling a little grumpy and moody about his illness, and his doctor takes him to see cheerful, brave children in a cancer ward. Writer Jeffrey Lewis (once of "Hill Street Blues") is straining for effect. And he's made Don and his family too well off, too well adjusted, for any real moments of truth to occur.

These aren't typical Americans. These are people who have wine every night with dinner.

The story is further hoked up with Don's visit to a former lover who also happens to be a therapist. Don's wife spies them getting into a car; aw-oh! These really don't seem like the raw, traumatic problems sick people have. And the show's doctors get just about as much sugar coating as all the other TV medical shows have lavished on them.

"Public squeamishness about colon-rectal cancer costs lives," lectures Prosky, his offscreen role patterned too clearly after the Stage Manager from "Our Town." The informational points driven home by the program are surely valuable and worth making. Unfortunately, as drama, "Lifestories" suffers from a suffocating sterility.