President Reagan agreed yesterday to withdraw the nomination of F. Keith Adkinson to a post on the Federal Trade Commission, after it became clear that Adkinson did not have enough support to be confirmed by the Senate Commerce Committee.

Adkinson had asked the president to withdraw his nomination last Friday, just three days before the committee was scheduled to vote on his appointment. "My assessment . . . is that there is simply not enough support for my nomination among the members of the Senate Commerce Committee for the nomination to be favorably reported," Adkinson explained in a letter to the president.

According to committee sources, a clear majority of the committee was ready to vote against the Washington attorney yesterday, had his nomination come up, with all of the committee's eight Democrats and at least two Republicans prepared to block the appointment.

There was no indication who would replace Adkinson. All White House officials would say is that "there will be an announcement on a replacement." However, they declined to say when that announcement would be made.

Adkinson's nomination stirred up considerable controversy from the moment he was mentioned as a candidate. First, Democrats were skeptical of his party affiliation because although a Democrat, he served as director of Democrats for Reagan in the 1980 presidential campaign.

But even more significant to the committee members were charges that Adkinson acted improperly while he was a staff member with the Senate permanent investigations subcommittee in the late 1970s. An FBI report on Adkinson caused several senators to question the propriety of a book contract Adkinson signed with a key subcommittee witness.

That report prompted a broader committee probe into Adkinson, leading the committee's ranking minority member, Sen. Howard Cannon (D-Nev.), to accuse Adkinson of perjury during his confirmation hearings. Cannon charged that Adkinson misrepresented his role in the book contract and a separate movie deal that was to have been based on subcommittee matters.

Adkinson, continuing to fight vigorously for his appointment, repeatedly denied all the charges levied against him and charged Cannon with "a gross abuse of public office" for making the accusations. He had the strong personal support of Reagan who made several phone calls to committee members urging his confirmation.

Nonetheless, Adkinson concluded after tallying the committee votes, that even though "it goes against my nature to run from a fight when I believe the position I am fighting to defend is right. . .I have no desire to engage in a fight, which might result in a failure, which could be unfairly counted against your administration."