Abe Pollin, whose Capital Centre is big on the map of Prince George's County, plunged into the quest for cable-TV riches yesterday from Montgomery County, where he has lived for 30 years.

Pollin and Maclean Hunter Cable TV Ltd., J. Barry Gage, president, confirmed at a news conference that they have combined to create 1st County Cable, a partnership that will compete with perhaps a dozen other well-heeled concerns in the bidding.

Asked if his basketball Bullets, hockey Capitals and other sports events emanating from the Centre would be available for telecasts by another firm, should it win the Montgomery franchise, Pollin said: "Obviously, anybody who wins the franchise will be coming to Capital Centre looking for programming. And obviously some programming would be forthcoming. I can assure you as the owner, part owner, of the cable company and the owner of the Capital Centre that a lot more would be forthcoming from the Capital Centre if Maclean Hunter is awarded the fran-chise . . ."

He stressed that the two ventures -- ownership of the sports franchises and the cable franchise application -- are "totally separate." But, he said, "the fact that I have the Centre and the teams puts me in a unique position. If I can use the unique position to help acquire the franchise, then I can do something for the citizens of Montgomery County."

Gage said the partnership was 50-50 between Pollin and Maclean Hunter, which branched into broadcasting from a vast publishing base in Canada, grossing $313 million in overall operations and $46.6 million in cable-TV revenue in Ontario, Michigan and New Jersey in 1980.

Gage estimated construction costs for the Montgomery system at $75 million.