BALTIMORE, NOV. 7 -- Bowie State University has come upon boom times lately but they may prove to be fleeting.

After struggling for students throughout much of the 1980s, its enrollment grew by 400 this fall, and the school recently won state permission to expand by 50 percent by the end of the decade. Nevertheless, administrators at the predominantly black campus are considering whether, for next year, to turn some qualified applicants away.

The possibility, unthinkable a few months ago, is a side effect of the budget problems within the University of Maryland system.

On orders from Gov. William Donald Schaefer, Bowie and the university's 10 other campuses are returning 6 percent of their subsidies. And today, the Board of Regents, acting again on state orders, finished a second distasteful chore: carving $39 million from the $649 million subsidy it had planned to seek for next year.

According to campus administrators, the double blow reverses most of an unprecedented infusion of state aid that the schools have gotten during the last two years. The reductions, they said, will make it harder to comply with a 1988 law intended to improve Maryland's higher education system.

After starting to spruce up the quality of teaching, student services and facilities, administrators are now confronting unpleasant choices: whether to hire fewer professors, keep antiquated science equipment, postpone repairs of aging buildings or -- in Bowie's case -- reject a long-awaited chance to grow.

"We can't keep saying to the teaching staff, the people in the records office, the people in counseling and financial aid, 'You are going to have less money but 1,000 more students," said James E. Lyons, president of the 4,200-student Bowie campus in Prince George's County. "Can you ask someone who had 30 students in a class to teach 50?"

Before today's vote, the regents asked presidents how much the smaller-than-expected budgets would hurt, and they responded with tales of pain.

At College Park, the state's flagship campus, administrators have called off the fourth installment of a five-year plan to lower undergraduate enrollment by 7,200 students, according to President William E. Kirwan.

He said the school had deferred the plan, one of its major strategies to improve undergraduate education, because next year's subsidies will not cover the tuition forfeited by cutting its student body.

At Towson State University, the campus has pared five positions from its police force, according to President Hoke L. Smith. Smith said he worried that the cuts may have contributed to the sexual assault of a student on campus last week.

Since 1988, schools have invested the additional money in ways that are difficult to reverse, such as raising salaries to recruit better professors, said Thomas Bellevance, president of Salisbury State University. "It is not a matter of someone saying, 'Well you've gotten all this money, why can't you live with a stable budget now?' We can't," he said.

Chancellor Donald N. Langenberg acknowledged that finances were tighter than expected but tried to put the best face on the matter. He noted that many states are confronting the economic problems that are now squeezing the university.

While recommending the reduced budget, the regents unexpectedly rejected a suggestion by Langenberg to let schools charge students more.

On a tie vote, the board defeated a proposal to let schools raise tuition by 6 percent next year for full-time Maryland undergraduates. Apparently surprised by the outcome, board leaders quickly convened a closed meeting without taking the vote required by law. Afterward, they said the session was warranted because the issue was sensitive.

In the end, the regents voted to limit next year's tuition increase to 4 percent, the level they had originally set. The regents' vice chairman, Roger Blunt, said, "It is important no one thinks we are putting {the schools' financial hardships} on the backs of our students."