Étienne-Émile Baulieu

Baulieu has had an ongoing interest in dehydroepiandrosterone (DHEA). In 1960 he demonstrated that DHEA was the main adrenal androgen, was largely conjugated as a hydrophilic sulfate, and described its metabolism and functions. He worked to uncover the production of estrogens by the placenta during pregnancy and this led to the concept of DHEA being a "prohormone". Upon the invitation of Seymour Lieberman Baulieu became visiting scientist at the Columbia University in 1961–1962, and during this time he met Gregory Pincus, the father of the "birth control pill". Baulieu then turned to more studies in contraception and in the regulation of fertility and pregnancy. He became a pioneer in the description of intracellular sex steroid receptors and identified major intracellular participants such as the heat shock proteins. He worked on the progesterone receptor and androgen receptor. While steroid receptors are generally found within the cell, Baulieu identified a membrane receptor for a steroid hormone in Xenopus laevis.

Baulieu discovered that DHEA and pregnenolone are produced in the brain and introduced the term "neurosteroids" in 1981.[5] These steroids are active in the nervous system, help repair myelin, protect the nervous system, and enhance memory. Such agents may prove to be useful in the maintenance of brain function during age, and Baulieu suggests that use of DHEA in the elderly may ameliorate certain age-associated deficits including memory loss and depressive mood.[6] Baulieu conducts clinical research about the potential benefits of DHEA in the elderly population.[7]

Baulieu is worldwide known[2] for his work on RU486 (Mifepristone) and has been termed the "Father" of the abortion pill.[8] Baulieu who had identified the progesterone receptor suggested to Roussel-Uclaf to modify the progesterone molecule to create an anti-progesterone.[9] Georges Teutsch then synthesized an agent that became initially known as RU468 in 1980. Baulieu investigated the actions of this agent as an anti-progesterone steroid that proved to be able to induce early abortion and became more effective in conjunction with misoprostol. As a proponent of a nonsurgical approach to abortion Baulieu became an advocat RU468 even when the company withdrew from the product[9] and propelled him into the limelight of the abortion debate.[10] As an anti-progesterone RU468 also has other potential such as in the treatment of certain conditions (breast cancer, brain cancer, endometriosis, diabetes, hypertension), and the anti-cortison activity he discovered may be useful to manage depression or Cushing's syndrome.

Baulieu has taken increasingly more interest in what he has called the "longevity revolution", that people are living longer, and its implications.[11] As part of this, he is investigating the potential of hormonal substitution such as DHEA to increase well-being in old age.[7] The "Institute Baulieu" was started in 2008 to address issues that are detrimental to health in older people. One focus of research in the 2020 decade is finding ways to decrease the problems of the elderly as to functioning independently.[12][13]