© Nature Publishing Group 1977 Nature Vol. 269 27 October 1977 With precise and specific measurements for plasma hormone, it became clear that many of the earlier guesses were incorrect. For example, the radioimmunoassay proved that only a minority of diabetics have an absolute deficiency of insulin. Most diabetics have normal or supernormal amounts of insulin which is biologically intact but the cells of these diabetics are subnormally responsive to insulin. Yalow and Berson not only introduced the radioimmuno- assay for insulin but applied the method to study the physiology of many other peptide hormones, including growth hormone, parathyroid hormone, adrenocortico- tropin and gastrin. They also used this approach to devise a very sensitive method for detecting hepatitis virus and its antibodies in blood, which is widely used in blood banks in the United States and elsewhere. Other applications to problems of infectious diseases are now emerging. Although just beginning, the extension of radioimmunoassay to measure blood levels of drugs, including cardiac glycosides, anticonvulsants and antibiotics, has made it much more feasible for physicians to achieve therapeutic effeots without sustaining serious untoward effects of these agents. The principle of competitive binding assays has been extended beyond antibodies to other binding substances of appropriate specificity and affinity. In the light of these extraordinary scientific accomplish- ments, it is interesting to recall Dr Yalow's own modest personal and academic background. Born in 1921, she was raised in the South Bronx, the area that is now recognised as the most devastated in the urban United States. She was the first physics major at Hunter College, and although she graduated magna cum laude and phi beta kappa, her future was clouded by the fact that she was both Jewish and female, two traits which were not considered to favour success in physics in those days. In part because the military draft was depleting the ranks of eligible males, Dr Yalow was accepted by the University of lllinois, and after receiving her Ph.D in physics she returned to New York, where she worked until the end of the Second World War. In 1947, when applications of radioactive isotopes to clinical medicine were in their infancy, Dr Yalow joined the newly formed radioisotope unit of the Inadvertent collaboration George Fink on Roger Guillemin and Andrew Schally DR Roger Guillemin of the Salk Institute and Dr Andrew Victor Schally of the Veterans Administration Hospital, New Orleans, were awarded the Nobel prize in physiology and medicine for isolating, characterising and synthesising three polypeptides whioh mediate the neural control of the anterior pituitary gland. The discoveries of Schally and Guillemin have already proved significant for clinical and basic medical science and are likely to offer new and safer methods for the control of population size. The delight of neuroendocrinologists will only be dampened by the fact that the untimely death in November 1971 of Geoffrey Wingfield Harris, FRS, prevented him from sharing the fruits of his lrubours. As a medical student at Cambridge, Harris was the first (1937) to provide experi- mental proof for the then tentative view that the anterior pituitary gland was controlled by the central nervous system. The elegant studies carried out by Harris in the l 940s and early 1950s, alone and in collaboration with Dora Jacobsohn and the late John Green, established beyond doubt that this control was mediated by a neurohumoral mechanism involving the transport by hypophysial portal Veterans Administration Hospital in the Bronx where she has worked ever since. Dr Berson, from a similar background, joined the radioisotope unit in 1950. His participation in the re- search was much less direct after 1968 when he assumed the chairmanship of the De- 1pa,rtment of Medicine of the Mount Sinai School of Medi- cine. In spite of his sudden death four years later, there has continued a flood of ex- citing new studies from the lruboratory (renamed the Solomon A. Berson Research Laiboratory) at the Bronx Yalow V e t e r a n s Administration Hospital under Dr Yalow's 747 solo leadership. It has become clear that each peptide hor- mone in the blood is not a single substance but is rather a family of related peptides that include the active hormone, modifications of the active hormone, precursors and de- graduation products, as well as ,phylogeneticaHy related peptides. Dr Yalow has been the major contri:butor to this area over the last decade and has extended these observations to numerous biological problems in vivo. Her achievements are the subject of editorials in The Daily News and The New York Post as well as the subject of hundreds of sermons in churcht:~ and synagogues throughout the area. Dr Yalow is being viewed as an example of how talented and determined people of modest background can become world champions even in today's America. Women's groups aII over North America have turned to her as a symbol. The Urban Crisis Task Force, which has its headquarters in the South Bronx, sees her as an ideal and has decided to name one of their new housing projects in her honour. 0 vessel blood of chemical substances from the hypothalamus to the anterior pituitary. The three polypeptides and their aminoacid sequences are: thyrotrophin releasing factor (TRF) pyro Glu-His-Pro- NH2; gonadotrophin releasing factor (GnRF) pyro Gly- His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2; and somatosta- tin (or somatotrophin release inhibiting factor, SRIF) H-Ala- Gly-Cys-Lys-Asn-Phe-Phe-Trp-Lys-Thr-Phe-Thr-Ser-Cys-OH. Synthetic TRF and GnRF are now widely used in the investigation of thyroid dysfunction and infertility, re- spectively. Because TRF releases prolactin as well as thyrotrophin , the tripeptide is also used for investigating patients in whom prolactin secretion appears to be abnormal. Conceivably, antagonists of TRF may prove useful for controlling hyipe8)rolactinaemia, a condition frequently associated with infertility in women, and for the control of hormone dependent tumours of the breast. Superactive analogues of GnRF, made by substituting a D-aminoacid (for example D-Trp, D-Ala or D-Leu) for Gly' and an ethylamide group for Gly 10 , are being investi- gated mainly by Schally's group with a view to improving the precision of ovulation in women who prefer to or must use the rhythm method of fertility control. The parent decapeptide has already been used successfully for the treatment of certain types of infertility in men and women. Because GnRF will only discharge the amount of luteinis- ing hormone (LH, the hormone which triggers ovulation) normally available for release, the risk in terms of pro-