Congress on Tuesday jumped into its first round of hearings on drug prices for the year, vowing to take action on a problem that the president and the public see as a top concern for the country.

The Senate Finance Committee and the House Oversight Committee began hearings Tuesday morning aimed at investigating the causes of high drug prices.

Sen. Chuck Grassley, R-Iowa, who became chairman of the Finance Committee this year, said in opening remarks that tackling high prescription drug costs is a priority for him, and blasted drug companies for agreeing to speak to lawmakers privately but not publicly at the hearing. The committee, he said, would extend an offer to the companies appear again in the future but would be "more insistent next time."

"I want to express my displeasure at the lack of cooperation from the pharmaceutical manufacturers recently , " he said.

Testimonies came instead from Doug Holtz-Eakin, president of the American Action Forum and former head of the Congressional Budget Office; Mark Miller, vice president of healthcare at the Laura and John Arnold Foundation; Dr. Peter Bach, director of Memorial Sloan Kettering Center for Health Policy and Outcomes; and Kathy Sego, the mother of a child who needs insulin to manage Type 1 diabetes.

Sego shared that her son, Hunter, once rationed his insulin after learning it would cost $1,700 for the month. The family often stretches its utility bills in order to afford the medication.

"I’m heartbroken to know that my son felt he was a financial burden to us," she said. "Money over life is not the choice I want him to make, and I agonize over the idea that this could happen again."

In the Oversight Committee, lawmakers will also hear from a mother, Antroinette Worsham, who has two daughters that depend on insulin; as well as Catherine Alicia Georges, national volunteer president at AARP; Dr. Aaron Kesselheim, associate professor of medicine at Harvard Medical School; and Gerard Anderson, professor of health policy and management at the Bloomberg School of Public Health at Johns Hopkins University.

The Trump administration has proposed policies for reducing drug costs, but will need Congress to act on some of them. Health and Human Services Secretary Alex Azar wrote in STAT opinion piece Tuesday that the Trump administration would be unsatisfied with work on prescription drug prices until it saw the list prices fall. One analysis found that average list prices for certain drugs increased by an average of 6 percent at the start of the new year.

Federal lawmakers have introduced bipartisan bills to let people import drugs from Canada, and to end a practice in which brand-name drugs won't provide copies of their drugs to generic companies, limiting their ability to bring cheaper drugs to market.

Another bill, authored by Grassley and Sen. Ron Wyden of Oregon, who is the top Democrat on the Finance Committee, would close a loophole in Medicaid that pharmaceutical companies use to misclassify their drugs to get higher reimbursements.

Tuesday's hearings will serve as an early indication as to whether Republicans and Democrats are able to work together on drug prices.

Democrats have said they remain committed to a plan that would let the HHS secretary directly negotiate drug prices in Medicare Part D, which are otherwise negotiated by private plans. Republicans and the Trump administration remain opposed to that approach, but HHS is considering letting plans negotiate another part of Medicare, known as Part B, that would curb prices for drugs administered in a doctor's office rather than at the pharmacy.

Last year, the pharmaceutical trade group Pharmaceutical Research and Manufacturers of America spent more money lobbying Congress than any other time in history, reaching a record $27.5 million in spending. The lobbying occurred at a time when Republicans controlled all branches of government.