One Friday night two weeks ago, a group of about 100 businessmen, affluent doctors, erstwhile politicians and others interested in affecting or observing the flow of power, gathered in a Prince George's County hotel banquet room, and munched stuffed, fried, roasted and sliced appetizers.

They had paid $150 each to attend a fund-raiser for Larry Hogan, the Republican county executive. The gathering was held at the Ramada Inn, the traditional Republican stomping ground for such affairs, just a stone's throw across the Beltway form its Democratic equivalent, the Sheraton Inn.

With a red carnation poked in his buttonhole, Hogan took it all in -- a slightly strained smile plastered on his face as he nervously watched reporters and conversed with his guests, large contributors to his past and future political campaigns.

"You might be wondering why we're having this fund-raiser (at $150 a head, no freebies, the largest amount ever charged in the county) when this is not an election year," said one of Hogan's closest political associates, Gerard Holcomb, after the crowd had been pacified by the open bar and delicate rolls stuffed with slices of rare roast beef. "This is just money we will be able to put in our sock for our candidate (Hogan) until he tells us which way he wants to go."

The "way" to which Holcomb was referring is political talk for which office Larry Hogan, the county's only elected Republican, will run when his county executive's term expires in 1982. After nearly two years in office, Hogan -- a somewhat paunchy, middle-aged man who seems to love mud-slinging and a good political fight -- maintains an unusually high popularity rating, according to a recent poll. Running for reelection as county executive would probably present no challenge, his associates believe.

Politicians do not as a rule like to admit publicly that they have greater political ambitions. Even when they have discussed those ambitions with the "inner circle" -- thus guaranteeing wide circulation of their intentions -- most politicians will express sublime satisfaction with their current jobs.

Viz. Larry Hogan's statements over the past few weeks: "I love my job. I have the greatest job in the world. Why should I leave it? This is really a great job."

But the fund-raiser, which the Hogan circle says brought in about $40,000 for their hero, and Hogan's recent speechmaking forays outside his home county seem to confirm what the Prince George's rumor mill, a surprisingly accurate weathervane in this politics-obsessed county, has been intimating for the last few months: Larry Hogan is seriously gearing up to run for governor or U.S. senator in 1982.

When pressed Hogan will say first, of course, that he loves his job, and second, that he sees several options available when his term runs out: "I could run for governor, county executive again, senator or nothing. I have no definite plans to do anything right now."

He will also say, once he's been forced onto the subject, "If you were to say (to Hogan) 'you can take any job you want,' I'd say I want to be governor. I like being an administrator more than a legislator."

Hogan and his political associates believe that Hogan could beat incumbent Democratic Sen. Paul S. Sarbanes if the county executive made it through a Republican primary, where in 1974 Hogan went down to ignominious defeat in his quest for governor.

However, since that setback to his statewide ambitions, Hogan has been trying to bridge various ideological factions in the party -- playing an active role as a Republican national committeeman -- in an effort to maximize his chances of future success in Maryland politics.

In a future Senate race, Hogan and his aides see a number of Republican contenders: U.S. Rep. Robert Bauman, as Eastern Shore conservative with a penchant for going for the jugular that may exceed Hogan's; Rep. Marjorie S. Holt, another well-known and popular conservative; and Anne Arundel County Executive Robert Pascal could spell doom for Hogan's chances.

In a gubernatorial race, the other expected Republican challengers are less formidable. The question, in the mind of Hogan's associates, becomes Hogan's ability to beat Democratic incumbent Harry Hughes.

Hogan aides concede that Hughes would have to make some political mistakes, anger a few more constituent groups if Hogan, or any republican, is to have a chance at beating him in 1982.

"If Hughes continues to look tough (in 1982), Larry will have to wait him out," said Holcomb. "He could take on Sarbanes and then (four years) after that he could try for governor."

If Hogan decides to stay where he is, a decision he apparently believes he must make by November, he will try to ensure that during his next term as executive, he has some Republican company on the County Council. Hogan has been preparing for that possibility over the last 18 months as executive -- as he and the council have fought over everything from appointments to protocol -- by helping a slew of Republicans obtain visible, high-level county jobs, good springboards for a political race. In the past 10 years, few Republicans in this solidly Democratic county have proved strong enough candidates to defeat the Democratic party slate.

Currently the 11-member council is all Democratic, but even the Democrats will concede that several of those seats are "weak." The weakness could be exacerbated if a group of so-called Independent Democrats make good on an on-going, behind-the-scenes effort to start up an antiparty ticket or a bipartisan slate.

But while Hogan and his associates are busy plotting his political future, so too are the Democrats, though as yet in a much more disorganized way. "There are a lot more of us. It just takes longer," said one prominent Democrat. "But we'll be ready. The water's just heating up now."