Fran Piret, an assistant campaign treasurer, was working all day yesterday at a desk that was covered with uneven stacks of money. White envelopes bulged with $10 and $20 bills. Paper clips held packs of personal and corporate checks made out in amounts ranging from $10 to $500.

This was the money the incumbent Democratic officials of Prince George's County had collected by selling $10-a-person tickets for a party they were holding for themselves last night at the county's community college, their first countrywide fund raiser of the 1978 campaign.

And it was this money, more than the event itself, that offered clear evidence of where the Prince Gorge's Democrats are at this year-who is in, who is out, who is ambitious, who is scared and, above all, who the politicians go to for financial support.

The financial records for last night's fund raiser show that many of the county Democrats sold blocks of tickets to special interest groups that they deal with on a regular basis.

Del. Frank Komenda sold a total of $700 worth of tickets to insurance industry lobbyists. As a member of the House Economic Matters Committee for the last four years, Komenda has been the committee's specialist on insurance bills. Last session, at the industry's request, he introduced two bills that would have required the non-profit Blue Cross-Blue Shield to conform to the regulations that control the rest of the industry.

Although both measures failed, Komenda said yesterday he felt the insurance lobbyists "recognized my efforts" by donating to his campaign.

County Council member Darlene White sold $500 worth of tickets to the Southern Maryland Hospital Medical Staff Fund. White has spent much of the last two years helping the controversial hospital get off the ground and at one point was listed as a consultant for the facility, which is regulated by the county.

Del. Fred Rummage, executive director of the Prince George County Educator's Association, (the teacher's union), had several leaders of his association sell tickets to scores of county teachers on his behalf.

Del. Nathaniel Exum sold $300 worth of tickets to Baltimore attorney James J. Doyle, one of the premier lobbyists in Annapolis who represents more than 20 special interest groups.

Doyle said he contributes to most political fund-raising events in the state. He said he picked out Exum in Prince George's for two reasons. First, Exum introduced a bill Doyle was pushing regarding the lean rates on life insurance policies. Also, Doyle noted that Exum is a member of the black political caucus in Annapolis.

"I try to get as friendly as I can with the black delegates," said Doyle. "I realize that they're becoming more conscious of their power as a group, that they can vote in bloc proportions."

In some cases, the relationship between the Democratic organization in Prince George's and special interest groups had been so firmly established over the years that the contributions come in unsolicited.This is particularly so with the law firm of Shipley, Knight, Manzi and Zanecki, considered the most influential zoning law firm in the county.

The firm contributed $200 to the 11 County Council members, who deal with the lawyers on a steady basis in zoning hearings. In addition, Council Chairman Francis White received $60 from V. Paul Zanecki and Council member Gerard T. McDonough got a extra $50 contribution from the firm.

Another influential zoning attorney, William V. Meyers, a close associate of County Executive Winfield Kelly, bought $100 worth of tickets from Council member Francis Francois, a longtime Kelly opponent who this year has patched up some of his differences with the county executive.

Francois also sold $150 worth of tickets to a road contracting firm, T. D. Burgess & Co. and $100 worth to Southern Maryland Land Associates, a real estate firm headed by Gilbert Giordano, s south county attorney and land speculator who has contributed heavily to Kelly's reelected campaign.

Giordano said he would support the entire slate of Democrats this year, "We in the business community have been very appreciative of their efforts over the last four years," he said. "They've brought about a business renaissance here."

The Prince George's Democrats hold every office in the county. The more than 50 incumbents have been told by County Executive Kelly and Senate President Steny Hoyer, a gubernatorial candidate, that they will all be assured spots on the Hoyer-Kelly ticket unless they "embarrass the party" or challenge another incumbent for higher office.

Last night's fund raising event demonstrated the extent to which the party leader - Kelly, Hoyer and Party chairman Lance Billingsley - have attempted this year to prevent primary challenges. Only incumbents were allowed to sell tickets for the event, despite the fact that the Hoyer-Kelly ticket has not been chosen yet.

There are only a handful of offices that may open up for new candidates. Three delegates - Craig Knoll, Ann Hull and David Ross - are not seeking reelection. Two other delegates - Andrew Mothershead and Lee Green - are expected to challenge the incumbent state senators in their districts and thus take themselves off the organization slate.

On the County Council, all 11 members have indicated that they will seek reelection. Kelly, however, has told his allies on the council that he will not support Darlene White, with whom he has frequently battled. Kelly has indicated to his associates that he would like to find a second black council member to replace White.

White, however, took out more than 350 tickets to sell for last night's event and maintains that she will get on the Hoyer-Kelly ticket.

Another council member who may be in danger of losing a spot on the ticket is Francis White, the chairman, who has been criticized by his colleagues for holding testimonials to Francis White, also, sold several hundred tickets for the party at the community college.

All the elected officials at the county courthouse took part in the event except Sheriff Don Ansell, who was recently found innocent of charges of misappropriating funds from a sheriff's banquet. Ansell has indicated that he may seek reelection without the organization's support.