Rosalyn Yalow co-invented radioimmunoassay

Person: Rosalyn Yalow
Lived: 1921–2011
Field: Medical Physics
From: American

The story

In 1947 the Veterans Administration launched a research programme to explore the use of radioactive substances in diagnosing and treating disease, and the Bronx VA Hospital in New York was one of the first hospitals chosen. Rosalyn Yalow, a nuclear physicist then teaching at Hunter College, joined it in December 1947 as a part-time consultant. Starting with little more than a janitor's closet, she equipped and developed the hospital's radioisotope service, and in 1950 she left teaching for full-time research.

Wanting a partner with medical expertise, she found Solomon Berson, a young doctor finishing his residency in internal medicine at the hospital, who joined the service in July 1950. Their partnership lasted 22 years, until Berson's death in 1972. Neither had specialised postdoctoral training; they learned from each other and were each other's severest critics, and colleagues said they sometimes finished each other's sentences.

They started with thyroid disease and blood volume, then turned to insulin, the hormone most readily available in pure form. They noticed that insulin injected into diabetic patients who had been treated with animal insulin disappeared from the blood more slowly than expected, and deduced that these patients had made antibodies against it. A leading journal, The Journal of Clinical Investigation, initially rejected their work. But in studying how insulin binds to antibodies, they realised they had a tool for measuring the hormone itself.

The principle was elegant. A known amount of radioactively labelled hormone competes with the unlabelled hormone in a patient's blood to bind to a limited supply of antibody. The more hormone the sample contains, the less of the radioactive version is bound, and measuring the radioactivity reveals the amount present, even in quantities far too small for earlier methods to detect. It took several more years to turn the idea into a practical test of insulin in human blood, and Yalow dated the era of radioimmunoassay, or RIA, to 1959.

The method allowed them to show that many people with adult-onset diabetes have plenty of insulin but use it inefficiently, overturning the belief that the disease was simply a lack of insulin. RIA went on to create what the Jewish Women's Archive calls an explosion of knowledge across medicine, and Yalow later wrote that it was used to measure hundreds of substances in thousands of laboratories in the United States and abroad. In 1977 it earned her the Nobel Prize in Physiology or Medicine.