The remarks of two respected Washington businessemen at a commercial real estate symposium earlier this week should become required reading (or listening when tapes become available) for developers and local public officials.

For the 400 or more developers, leasing specialists and others who attended the session at the National Housing Center, the panelists' remarks were a sobering forecast of development trends in downtown Washington.

In short, they said that the rapid commercial development that changed the face of downtown Washington in recent years has leveled off. And for the remainder of this decade, at least, developers will have to scale down their plans and develop new sources of financing.

What makes this forecast more compelling than usual is that it's shared by a lender and a developer.

Although they spoke from different perspectives, the conclusions of D.C. National Bank President Thomas Condit and developer John E. Akridge III were essentially the same: The local economy has changed and lenders and developers will have to adjust.

The immediate problem is the glut of office space that is the legacy from a building boom that began in 1975.

"You see a lot of cranes around D.C. right now, and you will continue to see them," Akridge noted. "But you will not see many more in the foreseeable future."

He believes that the approximately 10.5 million square feet of office space scheduled to be delivered in buildings downtown by the end of 1984 is "too much" to be absorbed on an annual basis. Indeed, "We do have too much space in the eastern sector of downtown," he said, referring to projects being built east of 15th Street.

As a result, he added, it will take at least two years to "work off" the oversupply of space east of 15th Street.

In retrospect, Condit views the 1975-80 period as an "historical fluke."

"The causes for it won't occur again. The financing that was available to help with that building increase won't be available anymore. The people who made loans from '75 to '80 won't be able to get money to make new loans from '80 to '90, and these changes are permanent, and they have to be recognized," Condit insisted.

What this means, he explained, is that the traditional sources of funds for major projects have had to adjust to those changes as well and that commercial real estate developers will feel the impact.

Institutional lenders such as banks, savings and loans and insurance companies "have lost their source of long-term money," Condit said.

"And that loss is in large measure permanent because their balance sheets have changed. All of their liabilities are very short-term in nature, and they're not going to borrow short-term to lend you at fixed rates."

Insurance companies, like banks and S&Ls, have had cash outflows, and "they're just not going to get back in the market," Condit warned.

In the meantime, pension funds are likely to be "the only game in town" for the next 10 years, but pension fund managers "are the most conservative people you will find," Condit said.

The message here is clear: The high-flyers who gambled that demand would quickly absorb space in new gleaming buildings will find it difficult to attract financial backing. Pension funds "will be dealing with very established, well known, relatively riskless situations," Condit warned.

He pointed out that, even now, the demand for existing buildings in Washington has risen sharply because "it's a nice safe thing to do with your money."

Meanwhile, developers should give some thought to who will need office space in the next 10 years, Condit suggested. He predicted that new economic growth will come from private industries serving the federal government.

Leading that growth will be the communications industry, which offers "tremendous opportunities for real estate developers," he said.

But the so-called high-tech firms that are part of that industry will find it difficult to grow and expand here because of the absence of venture capital in Washington, Condit contends.

Financing their projects will continue to be a problem, he warned developers. "You're dealing in new areas, new projects and concepts. And in my opinion, you're not going to get that financing through traditional lenders."

Thus, the District government has to play a very major role in providing new kinds of financing, Condit believes. said.

But the so-called high-tech firms that are part of that industry will find it difficult to grow and expand here because of the absence of venture capital in Washington, Condit contends.

Financing their projects will continue to be a problem, he warned developers. "You're dealing in new areas, new projects and concepts. And in my opinion, you're not going to get that financing through traditional lenders."

Thus, the District government has to play a very major role in providing new kinds of financing, Condit believes.