{{Short description|French endocrinologist (1916–1991)}} {{for|the German inventor and entrepreneur|Alfred Jost (inventor)}} {{Infobox scientist |name = Alfred Jost |image = |image_size =150px |caption = Alfred Jost |birth_date = 27 July 1916 |birth_place = Strasbourg |death_date = 3 February 1991 |death_place = |residence = |citizenship = |ethnicity = |field = Endocrinology |work_institutions = Collège de France |alma_mater = |doctoral_advisor = |doctoral_students = |known_for = anti-Müllerian hormone |author_abbrev_bot =|author_abbrev_zoo = |influences = |influenced = |prizes = |religion = |footnotes = |signature = }} '''Alfred Jost''' (1916&ndash;1991) was a French endocrinologist, and an early researcher in the field of fetal endocrinology.<ref>{{cite book |title=Gynecologic and Obstetric Investigation |url=https://books.google.com/books?id=T4VOAQAAIAAJ&pg=PA168 |year=1989 |publisher=Karger |page=168}}</ref> He is known for his discovery of the Müllerian inhibitor, now called anti-Müllerian hormone (AMH) or Müllerian inhibiting substance (MIS).<ref name="MatzukBrown2001">{{cite book |author1=Martin Matzuk |author2=Chester W. Brown |author3=T. Rajendra Kumar |title=Transgenics in Endocrinology |url=https://books.google.com/books?id=hXz1BwAAQBAJ&pg=PA42 |date=15 August 2001 |publisher=Springer Science & Business Media |isbn=978-1-59259-102-2 |pages=42–}}</ref> His research demonstrated how hormones affect the development of male and female sex characteristics.<ref name="Reed2012">{{cite book |author=Lori Reed |title=Governing the Female Body: Gender, Health, and Networks of Power |url=https://books.google.com/books?id=LM3DGsfHXCAC&pg=PA277 |date=1 February 2012 |publisher=SUNY Press |isbn=978-1-4384-2954-0 |pages=277–}}</ref>

==Career== Jost was a professor at the University of Paris, and was head of the Department of Comparative Physiology there in 1972.<ref>{{cite book |title=The Johns Hopkins Medical Journal |url=https://books.google.com/books?id=noRMAQAAIAAJ&pg=PA37 |year=1972 |publisher=Johns Hopkins Press |pages=37–38}}</ref> Jost was known for applying surgical methods to fetal endocrinology. He also taught many pre-doctoral students.

==Research== During the 1950s and 1960s Jost studied the mechanism of somatic sex differentiation;<ref name="Becker2002">{{cite book |author=Jill B. Becker |title=Behavioral Endocrinology |url=https://books.google.com/books?id=D6TnKbTRBJoC&pg=PA77 |year=2002 |publisher=MIT Press |isbn=978-0-262-52321-9 |page=77}}</ref>{{failed verification|reason=this page doesn't mention Jost at all|date=September 2025}} his research showed that male characteristics must be imposed on the fetus by the testicular hormones testosterone and AMH,<ref name="Kappy(M.D.)2005">{{cite book |author1=Michael Steven Kappy |author2=David B. Allen (M.D.) |author3=Mitchell E. Geffner |title=Principles and Practice of Pediatric Endocrinology |url=https://books.google.com/books?id=JlqcQ0WhU_kC&pg=PA490 |year=2005 |publisher=Charles C Thomas Publisher |isbn=978-0-398-07554-5 |page=490}}</ref><ref name="Becker2002"/> and that in the absence or inactivity of these hormones, the fetus becomes phenotypically female.<ref name="MelmedPolonsky2015">{{cite book |author1=Shlomo Melmed |author2=Kenneth S. Polonsky |author3=P. Reed Larsen |author4=Henry Kronenberg |title=Williams Textbook of Endocrinology |url=https://books.google.com/books?id=YZ8_CwAAQBAJ&pg=PA903 |date=30 November 2015 |publisher=Elsevier Health Sciences |isbn=978-0-323-29738-7 |page=903}}</ref>

Jost also studied testicular differentiation, in collaboration with Solange Magre. He was the first to show that testicular organization is heralded by the development of pre-Sertoli cells, which progressively surround germ cells to form seminiferous tubules.

== Death == He died February 3, 1991, at age 75,<ref name="Bardin2014">{{cite book |author=C. Wayne Bardin |title=Recent Progress in Hormone Research: Proceedings of the 1991 Laurentian Hormone Conference |url=https://books.google.com/books?id=ez-aBQAAQBAJ&pg=PA1 |date=10 May 2014 |publisher=Elsevier |isbn=978-1-4832-1968-4 |page=1}}</ref> having retired from the Collège de France, but still active as the Secrétaire Perpétuel of the French Academy of Sciences.

==References== {{reflist}} * {{cite journal |author=Josso N |title=Professor Alfred Jost: the builder of modern sex differentiation |journal=Sex Dev |volume=2 |issue=2 |pages=55–63 |year=2008 |pmid=18577872 |doi=10.1159/000129690 |s2cid=26022942 }}

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{{DEFAULTSORT:Jost, Alfred}} Category:1916 births Category:1991 deaths Category:French endocrinologists Category:French sexologists Category:Members of the French Academy of Sciences Category:Foreign associates of the National Academy of Sciences Category:20th-century French medical doctors Category:Academic staff of the University of Paris Category:Members of the Royal Swedish Academy of Sciences

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