A medical center foundation reluctantly agreed to pay a $50,000 fee for a speech by former President Reagan but balked when his agency later sought a "significant increase," an official has acknowledged.

"We just thought enough was enough," Mac Burton, a vice president of the Tucson Medical Center Foundation, said Thursday.Burton refused to disclose how much more Reagan's agency wanted but said it was "significantly higher" than the original $50,000, which the foundation agreed to in February for a speech in March.

The fee would have been the highest ever paid by the foundation and its Greater Issues Series, Burton said. The series has featured such noteworthies as Henry Kissinger, Peter Ueberroth, Thomas P. "Tip" O'Neill Jr., James Reston, Jeane Kirkpatrick, Caspar Weinberger and Eric Sevareid.

The Washington Speakers Bureau, the Virginia-based agency that handles the Reagan account, refused comment beyond acknowledging that money "was the last item in our negotiations."

Reagan addressed a student leadership conference on March 20 at Arizona State University in Tempe. The school initially had agreed to pay him $50,000; however, ticket sales were slow and he agreed to appear without payment.