The president of Allbritton’s broadcasting division said Monday that he will step down by the end of the year, the latest in a series of changes at a Washington communications empire that includes Politico and local ABC affiliate WJLA-7.

Frederick J. Ryan Jr., 58, who has spent 19 years with Allbritton, serves as chief executive of Politico and president of the broadcast side of the company.

Ryan told his staff in a memo Sunday night that the recent sale of Allbritton Communications television properites, including WJLA, created the right time to pursue other avenues.

“I just felt this was a logical time to explore opportunities that have come my way,” Ryan said in an interview. “I have been approached about some things that have appealed to me and that I think are worth exploring, but I haven’t made any decisions.”

He declined to provide details, but said he would stay at Allbritton through the rest of the year. “I’m not going to announce anything until the broadcasting deal closes,” he said.

Ryan’s decision follows several recent moves by Allbritton. The company in July agreed to sell its eight television properties, including Newschannel 8, to Baltimore-based Sinclair Broadcasting Group for nearly $1 billion. The sale must be approved by the Federal Communications Commission and is expected to close later this year.

This month, Allbritton announced that it was acquiring a scrappy Web site called Capital New York, hoping to replicate the success of its Rosslyn, Va.-based Politico.

Ryan cited the sale of the television stations as the reason for his departure.

“I’ve really had a unique opportunity as president of an established broadcasting group to be able to grow it and do well. Similarly, I was delighted to be a co-founder of Politico and see the success that it has achieved. For me, it’s been the perfect combination. Since the television group is being sold, the opportunity to wear two hats will be gone. I figured this was the time to be thinking of next steps,” he said.

Politico’s newsroom is led by John Harris and Jim VandeHei, both former political reporters at The Washington Post. As chief executive, Ryan oversees both editorial and business sides.

Ryan, who is a lawyer, graduated from the University of Southern California and served as a White House assistant to President Ronald Reagan. He went on to work as Reagan’s post-presidential chief of staff from 1989 to 1995.

He will remain on Politico’s board of directors.