Attorneys for Prince George's County schools argued before a federal appeals court today that racial imbalance in their system was a result of demographic changes, not discrimination, and they asked the panel to overturn a 1983 court decision that found their schools had not been fully desegregated.

The county NAACP, which brought a discrimination lawsuit against the schools in the early 1970s and again a decade later, countered that the schools were never properly desegregated after a 1972 court order in response to the first suit.

The oral arguments before the 4th U.S. Circuit Court of Appeals were yet another phase in the 13-year-old desegregation saga in Prince George's. This time, the adversaries argued whether U.S. District Court Judge Frank A. Kaufman was correct in 1983 when he reopened the original case and set guidelines for the racial composition of schools. He said no school should have less than 10 percent or more than 80 percent black enrollment.

While the appeal is being decided, Kaufman continues to oversee his 1983 desegration order, which included appointment of an expert panel scheduled to make recommendations by Feb. 1 on how to desegregate the system further.

The case has national implications, school officials said, because the appeals court decision could set a precedent on whether schools must react to changes in the racial makeup of the community to keep enrollment racially balanced.

"It raises the question . . . should a school system be held responsible for realigning its school boundaries every time people up and move," said school spokesman Brian J. Porter.

Board of Education attorney Paul M. Nussbaum said that given the influx of black residents to the county and the movement of blacks there during the 1970s, "it would be inconceivable . . . for such a community to run its school system" within the guidelines for racial balance originally established in 1972 by Kaufman. Black enrollment in the schools has increased from about 24 percent to nearly 58 percent since the early 1970s, according to school figures.

The NAACP, however, said the population shifts cannot be used as an excuse for having schools with an overwhelming black or white majority. It cited a 1980 Alabama case that said that "not until all vestiges of the dual segregated system are eradicated can demographic changes constitute a legal cause for racial imbalance."

Attorneys for the civil rights organization told the appeals court that Kaufman was correct in finding in 1983 that the schools had never fully desegregated. Moreover, administrative decisions, particularly a 1980 revision of the 1972 busing plan, have had the effect of resegregating schools, the NAACP attorneys argued.

Nussbaum and school attorney George D. Solter pointed to a statement in 1975 by Kaufman that the school's desegregation plan "was meeting constitutional obligations and standards" as an indication that schools had been desegregated and the court had relinquished jurisdiction. As a result, they said, the judge should not have granted the NAACP request that the 1972 case be reopened almost a decade later.

"There's got to be some time when a school board is relieved of its past discrimination policies," said Solter.

But Judge Francis D. Murnaghan replied that he did not interpret Kaufman's 1975 statement as a relinquishment of the case. Kaufman, he said, may not have maintained "day-to-day supervision" but decided to take the case back when the school system failed to desegregate.

The NAACP also challenged parts of Kaufman's 1983 decision, specifically that there was no evidence of intentional discrimination in the disproportionately low numbers of black students in programs for the talented and gifted and disproportionately high numbers of blacks in special education