WASHINGTON - The business of developing and selling new drugs is fraught with peril and setbacks. Billions of dollars are at stake. Nerves are on edge. Tempers flare.

Just ask Dr. John B. Buse, a medical researcher who testified at a House hearing on Wednesday about the safety of the popular diabetes drug, Avandia.

Dr. Buse described name-calling and what he said was the veiled threat of a lawsuit by a high-ranking drug company executive in 1999 after he had criticized Avandia at a medical meeting.

He said the executive called him a "liar" and "scoundrel" in criticizing him to his supervisor at the University of North Carolina medical school, where Dr. Buse was an associate professor and has since become the chief of endocrinology.

Dr. Buse did not name the executive, but he was later identified at the hearing by another company official as Dr. Tadataka Yamada. In 1999 Dr. Yamada was the chief of research and development for Avandia's maker, SmithKline Beecham, which is now called GlaxoSmithKline.

Dr. Yamada is a well-known scientist who left GlaxoSmithKline in June 2006 to become director of global health programs for the Bill and Melinda Gates Foundation. A spokesman for the Gates Foundation, Joe Cerrell, said that Dr. Yamada was not reachable for comment.

The committee released a letter Dr. Buse wrote in 1999 to Dr. Yamada in which he expressed anger and frustration. "Please call off the dogs," Dr. Buse wrote. "I cannot remain civilized much longer under this kind of heat."

Some members of the Congressional panel, the House Committee on Oversight and Government Reform, said the company's behavior toward Dr. Buse was inappropriate and unacceptable. "We cannot have a post-regulatory environment where manufacturers intimidate scientists," said Representative John Yarmuth, Democrat of Kentucky.

In documents and in a prepared statement, he said his problems with the company began in 1999, the same year Avandia was approved by the Food and Drug Administration, during a presentation at a meeting of the American Diabetes Association.

Dr. Buse recalled trying to squeeze two hours of scientific data into a 25-minute speech to the group, in which he said the data suggested Avandia raised the risk of chest pain and heart attacks by 50 percent.

"In the week that ensued," Dr. Buse said in his prepared statement, "there were a number of phone calls from SmithKline Beecham. During these calls, it was mentioned on two occasions that there were some in the company who felt my actions were scurrilous enough to attempt to hold me liable for a loss in market capitalization." He was referring to a decline in the company's stock price.

The company also contacted the chairman of medicine at the University of North Carolina, Dr. Fred Sparling. In his letter to Dr. Yamada, Dr. Buse wrote, "I was not upset when my chairman called me into his office to tell me that some in your company perceive me as being 'for sale,' as he knows me well enough to doubt it."

In testimony yesterday, GlaxoSmithKline's current chief of research and development, Moncef Slaoui, who succeeded Dr. Yamada in that job, said that Dr. Buse made an error in the presentation he gave in 1999.

Dr. Buse said he ultimately signed a statement clarifying his position about Avandia that the company could present to financial analysts. But in his letter to Dr. Yamada, he said: "I cannot change my opinions in the absence of new data or understanding, in large part because I am not for sale."

After the hearing, Senator Max Baucus, the Montana Democrat who is chairman of the Senate Finance Committee, and Senator Charles E. Grassley of Iowa, the ranking Republican on the committee, asked that GlaxoSmithKline and the University of North Carolina supply additional information about any retaliation against Dr. Buse.