Rosalyn Sussman Yalow (1921–2011)

In 1977, Rosalyn Yalow became the second woman to win a Nobel prize in medicine for co-developing radio-immunoassay (RIA), a groundbreaking technique that uses radioactive isotopes to quickly and precisely measure concentrations of hormones, vitamins, viruses, enzymes, drugs, and hundreds more substances. The technique is so sensitive that it can detect a teaspoonful of sugar in a body of water 62 miles long.

As a result of Yalow’s work, many diseases and conditions can be diagnosed, treated, or tested. Children with dwarfism can be treated with human growth hormones; fetuses are checked for serious deformities; newborns are tested to prevent retardation; blood banks are screened for diseases; and athletes are tested for drug abuse.

Born in Bronx, NY, Yalow’s interest in chemistry began at Walton High School. By the time she got to Hunter College, an all-women’s school in New York (now part of the City University of New York), two professors managed to pique her interest in physics, influencing her decision to switch majors.

Yalow almost didn’t pursue a doctoral degree in physics for fear that graduate schools would not accept her or offer financial aid because she was a woman. Even her parents urged her to become an elementary school teacher for “practical reasons”. But her professors persisted. The physics department at University of Illinois at Champaign-Urbana offered Yalow a teaching assistantship in 1941, where she would be the only woman on a faculty of 400 professors and teaching assistants.

Dr. Rosalyn Yalow at her Bronx Veterans Administration Hospital, Oct. 13, 1977, after learning she had won the Nobel Prize.

Yalow received her master’s degree in 1942 and Ph.D. in 1945. After a few jobs in electrical engineering and teaching, she decided to devote her career to full-time research. In 1950, Yalow began working with physician Solomon Berson with whom she gained clinical expertise while strengthening her physics, math, and chemistry. Together they discovered new ways to use radioactive isotopes to measure blood, study iodine metabolism, and diagnose thyroid diseases.

Later they decided to apply their methods to hormones, one of the most important classes of small peptides. Because insulin was the most readily-available hormone in a highly-purified form, the scientists began investigating the adult onset of diabetes. Yalow also had a personal interest in this area because her husband, Aaron, was diabetic. Among the endocrine gland disorders, diabetes affects the greatest number of people, making insulin uniquely important. Death is unavoidable without insulin and its ability to lower blood sugar.

Using radioisotopes, Yalow and Berson discovered the need to detect insulin antibodies at low concentrations to measure circulating insulin. Upon discovering that globulins (serum proteins) bound radioactive insulin in the blood of insulin-treated diabetics, they concluded that insulin injections immunized patients so that they develop insulin-binding antibodies, which keeps the insulin molecules in the bloodstream.

This was the first evidence that very small proteins could stimulate an immunologic response, and demonstrated how remarkably sensitive the radioisotopic technique is in measuring incredibly low concentrations of substances. In 1959, Yalow and Berson published their proof of studying the primary reaction of antigen with antibody using the radioisotopic method, which they labeled radioimmunoassay (RIA).

Before this revolutionary breakthrough, scientists could only analyze reactions between antigens and antibodies and those that produced visible precipitation or other evidence, such as the clumping of red blood cells. The RIA method revolutionized endocrinology—the study of ductless glands and hormones—and the treatment of disorders like diabetes. For the first time, doctors could diagnose conditions caused by minute changes in hormones and treat conditions with hormones.

In 1968, Yalow became a research professor at Mt. Sinai School of Medicine and chief of Nuclear Medicine Service at the Veterans Administration Hospital. For her work, she was recognized with the Albert Lasker Prize for Basic Medical Research and the following year she was awarded the Nobel Prize with Andrew V. Schally and Roger Guillemin for their work on radioimmunoassay. Berson was not recognized, because he died before the award was announced.

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  2. Rosalyn Yalow and Solomon Berson. (n.d.). Chemistry in History. Retrieved from
  3. The Nobel Prize in Physiology or Medicine 1977: Roger Guillemin, Andrew V. Schally, Rosalyn Yalow. (n.d.). Retrieved from.
  4. Pizzi, Richard A. (n.d.). Rosalyn Yalow: Assaying the Unknown. Modern Drug Discovery. Retrieved from
  5. Rosalyn Yalow: Nobel Prize Winner for Physiology or Medicine. (2008). Retrieved from
  6. McGrayne, Sharon B. (1998). Rosalyn Sussman Yalow. Nobel Prize Women in Science. (pp. 332-354). Washington, DC: Joseph Henry Press.

We cannot expect that in the foreseeable future women will achieve status in academic medicine in proportion to their numbers. But if we are to start working towards that goal, we must believe in ourselves or no one else will believe in us; we must match our aspirations with the guts and determination to succeed; and for those of us who had the good fortune to move upward, we must feel a personal responsibility to serve as role models and advisors to ease the path for those who come afterwards.” — Rosalyin Yalow