Paul Nelson, for 23 years the powerful staff director of the House Banking, Finance and Urban Affairs Committee -- including seven years as top aide to Committee Chairman Fernand J. St Germain -- is resigning to accept a top administrative job at Tulane University in New Orleans.

Nelson, who will become executive vice president of Tulane Nov. 1, departs amid a three-month-old grand jury probe of allegations that Rep. St Germain, a Democrat from Rhode Island, improperly accepted food, drink, travel and other entertainment expenses from lobby groups.

Nelson, asked if his departure was in any way connected to the grand jury inquiry, said, "There's no truth to it. I have been considering this {job} at Tulane for several months."

Nelson, whose peers in Congress call him "the doctor" because he has a PhD in economics from the University of Oklahoma, was questioned by the House ethics committee during a 14-month probe of St Germain on allegations that the congressman had enriched himself by engaging in business deals that involved potential conflicts of interest with his office.

The ethics committee questioned Nelson about several calls he made to federal regulators regarding an application from a Florida savings-and-loan institution that wanted to sell securities and that St Germain later invested in. The ethics committee last spring found that St Germain had violated some House rules by underreporting his assets but recommended no punishment.

Nelson, 58, was described by financial service industry analysts yesterday as someone whose years on the committee have given him an institutional knowledge about politics and day-to-day operations of Capitol Hill that will be hard to replace.

Nelson started on the banking committee in 1964, working as chief of staff under Reps. Wright Patman, then Henry Reuss and, starting in 1981, under St Germain.

"He's very close to the chairman and since you can't always get to the chairman he serves as a proxy," said Richard Whiting of the Association of Bank Holding Companies, a lobby group.

Nelson's replacement will be Lee Peckarsky, 36, who has worked as counsel on the banking committee for two years and, for nine years before that, in the office of legislative counsel of the House, a spokesman for St Germain said.

Richard Still, general counsel of the committee, is also considering resigning, according to committee aides, although a spokesman for St Germain and Still said he had not heard of any plans for Still to leave.