The Federal Trade Commission has voted, 3 to 2, to close four regional offices to save money, drawing "strenuous objections" of two senators who said it was "specifically instructed" by the Senate Appropriations Committee to keep three of them open.

"We are at a loss to understand why the commission would now consider a proposal which would be directly contrary to the instructions of Congress," Sens. Slade Gorton (R-Wash.) and Henry M. Jackson (D-Wash.) wrote FTC Chairman James C. Miller III.

On Wednesday Miller was joined by David A. Clanton and new commissioner George W. Douglas in supporting a move to close regional offices in Denver, Boston, Seattle and Los Angeles while Michael Pertschuk and Patricia P. Bailey opposed it. Under Senate instructions, the Denver office was to be closed while the others were to remain open.

Miller said the FTC will be $4.1 million in the red if it does not close the offices. The two senators and Pertschuk said the FTC should seek the extra money in a supplemental appropriation.

Pertschuk, calling the regional offices vital for the agency's consumer protection and antitrust activities, said if no supplemental is requested, he will propose letting one economist go for every person fired in the regional offices. The FTC's Bureau of Economics is Miller's pet and has remained the same size while the rest of the commission's staff has shrunk.