In 1954, Guillemin observed that pituitary cells did not produce hormones unless hypothalamic cells were present, supporting the theory that the hypothalamus controls the pituitary through hormones, dubbed releasing factors. Guillemin moved to Baylor College of Medicine in Houston to develop this finding. Andrzej V. Schally, known in the US as Andrew Schally, joined him in 1957. Their partnership dissolved after five years due to lack of progress and personal conflicts; Schally moved to the Veterans Affairs Hospital in New Orleans.[4]
Both scientists then worked independently, processing large quantities of hypothalami—Guillemin used over two million sheep hypothalami, while Schally used pig brains—funded by the U.S. government.[4] These release factors are present in an extremely low amounts in the hypothalamus, and it was hard to detect them using the instrumentation available at that time.[3] Their rivalry intensified, particularly regarding scientific credit. In 1969, as government funding was about to be cut off, Roger Burgus from Guillemin's team made a breakthrough, identifying the thyrotropin-releasing factor (TRF), which controls the thyroid gland. This achievement secured continued funding and led to the identification of another releasing factor, FRF, which controls reproductive systems. Guillemin and Schally discovered the structures of Thyrotropin-releasing hormone (TRH) and Gonadotropin-releasing hormone (GnRH) in separate laboratories. They were awarded the 1977 Nobel Prize in Physiology or Medicine for this discovery.[4]
In 1970 he joined the Salk Institute in La Jolla, where he was the head of the Laboratories for Neuroendocrinology until retirement in 1989. Here, he discovered somatostatin, and was "among the first" to isolate endorphins.[2] Guillemin protege, Wylie Vale Jr., established his own laboratory at Salk in 1977; their attempts of finding releasing factors was described as "yet another furious rivalry";[4] Vale's lab was first to purify and sequence the CRF.[4]
In 2007, Guillemin was an interim president of the Salk Institute.[2]
Guillemin signed along with other Nobel Prize winners a petition requesting a delegation of the Committee on the Rights of the Children of the United Nations to visit a Tibetan child who had been under house arrest in China since 1995, namely Gedhun Choekyi Nyima, recognized as the 11th Panchen Lama by the 14th Dalai Lama, Tenzin Gyatso.[citation needed]
Guillemin turned 100 on January 11, 2024,[5] and died in San Diego, California the following month, on February 21.[4][6] He was married to Lucienne Jeanne Billard for 69 years, until her death in 2021 at the age of 100. They had five daughters and a son.[2][4]
