WASHINGTON (Reuters) - The top two lawmakers on the U.S. Senate's antitrust panel have written to regulators expressing concerns about AT&T Inc's (>> AT&T Inc.) plans to buy DirecTV (>> DIRECTV) for $48.5 billion (30.30 billion pounds), including the impact on three regional sports networks.

Senators Amy Klobuchar and Mike Lee, the chair and ranking member of the Senate Judiciary Committee's antitrust subcommittee, wrote last week to Attorney General Eric Holder and to Tom Wheeler, chairman of the Federal Communications Commission, to urge that they take several key issues into consideration as they decide if the deal should be allowed.

In a letter dated Oct. 31, Klobuchar and Lee urged consideration of the effect the deal could have on consumers' access to broadband service, and worries over the loss of independent programming as the number of buyers for this programming shrinks.

They also urged a probe into whether the deal would prompt DirecTV to raise what it charges other companies to broadcast its three regional sports networks. The networks, known as Root Sports Northwest, Pittsburgh and Rocky Mountain, carry a variety of professional and college sports across 18 states.

"We urge you to take the above considerations into account as you conduct your respective reviews of the merger," Klobuchar and Lee wrote.

Some two dozen state attorneys general are also involved in the investigation.

As is usually the case when Klobuchar and Lee write to regulators about proposed mergers, they did not take a position on whether the deal should be approved.

Analyst Paul Gallant of Guggenheim Partners said in a research note that he saw the letter overall as positive for potential approval of the transaction. A decision was possible on the deal in March, he said.

Officials with AT&T and DirecTV were not immediately available for comment.

(Reporting by Diane Bartz, editing by Ros Krasny and David Gregorio)

By Diane Bartz

Stocks treated in this article : AT&T Inc., DIRECTV