WASHINGTON — After weeks of talks, drug industry lobbyists were growing nervous. To cut a deal with the White House on overhauling health care, they needed to be sure that President Obama would stop a proposal intended to bring down medicine prices.

On June 3, 2009, one of the lobbyists e-mailed Nancy-Ann DeParle, the president’s health care adviser. Ms. DeParle reassured the lobbyist. Although Mr. Obama was overseas, she wrote, she and other top officials had “made decision, based on how constructive you guys have been, to oppose importation” on a different proposal.

Just like that, Mr. Obama’s staff signaled a willingness to put aside support for the reimportation of prescription medicines at lower prices and by doing so solidified a compact with an industry the president had vilified on the campaign trail. Central to Mr. Obama’s drive to remake the nation’s health care system was an unlikely collaboration with the pharmaceutical industry that forced unappealing trade-offs.

The e-mail exchange three years ago was among a cache of messages obtained from the industry and released in recent weeks by House Republicans — including a new batch put out Friday detailing the industry’s advertising campaign supporting Mr. Obama’s health care overhaul. The broad contours of his dealings with the industry were known in 2009, but the newly public e-mails open a window into the compromises underlying a health care law now awaiting the judgment of the Supreme Court.