(b. Canyon City, Colorado, 2 May 1892; d. New Haven, Connecticut, 3 February 1943)
Edgar Allen discovered estrogen and investigated the hormonal mechanisms that control the female reproductive cycle. In so doing he helped to create the science of endocrinology, one of the most significant branches of modern biology.
Allen, the son of a physician, received his early education in the public schools of Pawtucket and Cranston, Rhode Island. He attended Brown University and earned all of his higher degrees at that institution: Ph.B.(1915), M.A.(biology,1916), Ph.d. (biology, 1921). During World War I his studies were interrupted for a short time by military service. In 1918 he married Marion Pfieffer of Providence; the couple had two daughters.
Allen’s distinguished academic career began in 1919 when he was appointed instructor in anatomy at Washington University, St. Louis, Missouri. In 1923 he moved to the University of Missouri, where he served initially as professor of anatomy and subsequently as dean of the medical school and director of university hospitals. In 1933 he returned to the east coast as professor of anatomy and chairman of the department at the Yale School of Medicine, a position he held until his death.
Allen’s Ph.D. thesis on the estrous cycle of the mouse (published in 1922) is a thorough description of the histological changes that occur in primary and secondary sex organs during the reproductive cycle. During the early 1920’s several investigators had suggested that the ovary might be the control center for this cycle; it was thought that the fluid content of the corpus luteum might be the active agent of control. Allen’s Ph.d. thesis cast doubt on this latter hypothesis. He noticed that at any given time during the cycle corpora lutea can be found in many different stages of degeneration, making it highly unlikely that they could be controlling a continuous series of progressive histological changes.
In 1923 Allen undertook a study of ovogenesis during sexual maturity and discovered that females are not born with a complete complement of ova; ova are continually formed in the germinal epithelium and the follicles that develop around them have a cycle of growth and decay not unlike that of the corpus luteum. This fact led Allen to suspect that the ovarian follicle, not the corpus luteum, might be the focus of control. In collaboration with a biochemist, E. A. Doisy, Allen proceeded to test this hypothesis by extracting a fluid from the follicle and determining its effects. He found that repeated injections of the follicular fluid produced histological changes that were identical to the early stages of normal estrus; when the injections were halted, the later phases ensued.
Allen and Doisy had discovered the existence and the effects of estrogen. Within fifteen years the other hormones that influence estrus were also discovered (see the work of Zondek, Aschheim, H. M. Evans and J. A. Long on pituitrin and Hartmann, Corner, Hisaw and Zuckerman on progesterone) and the relations between them were becoming clear. All of Allen’s subsequent investigations were concerned, in some way, with these sex hormones. He proved, for example, that estrogen causes the onset of puberty in immature female animals and demonstrated that the hormonal mechanisms of primates (including man) are very similar to those of rodents, on which the original studies had been done. Allen also studied the relation between estrogen and malignancy, in order to determine whether there is any similarity between rapid cell growth caused by estrogenic stimulation and rapid cell growth that is characteristic of cancerous tissue. In addition, Allen’s publications contain a wealth of methodological information that was of great value to subsequent researches in endocrinology.
Allen was a member, and president, of two scientific societies, the American Association of Anatomists and the Association for the Study of Internal Secretions. Brown, Yale, and Washington universities awarded him honorary degrees. The French government made him a member of the Legion of Honor (1937), and the Royal College of Physicians awarded him its Baly Medal (1941). He was also an advisory trustee (1939–1943) and member of the Scientific Advisory Committee of the International Cancer Research Foundation.
Allen’s total bibliography contains more than 140 items; it can be found in the Yale Journal of Biology and Medicine, 17 , part 1 (1944–1945), 2–12, along with his curriculum vitae. The Yale Journal, 15 (1943), 641–644, contains an excellent biographical sketch of Allen.
For an understanding of the development of follicular control, see, in the following order, “The Estrous Cycle in the Mouse,” in American Journal of Anatomy, 30 (1922), 297 (Allen’s doctoral dissertation); “Ovogenesis During Sexual Maturity,” in American Journal of Anatomy, 31 (1923), 439; and “The Hormone of the Ovarian Follicle; Its Localization and Action in Test Animals, and Additional Points Bearing Upon the Internal Secretion of the Ovary,” in American Journal of Anatomy, 34 (1924), 133. The last study was written in collaboration with E. A. Doisy.
Some of the extensions of his original idea can be found in “The Induction of a Sexually Mature Condition in Immature Females by Injection of the Ovarian Follicular Hormone,” in American Journal of Physiology, 69 (1924), 577; “The Menstrual Cycle of the Monkey, Macacus Rhesus...” in Contributions to Embryology, Carnegie Institute of Washington, No.380 (1927), p.98; and “The Estrous Cycle of Mice During Growth of Spontaneous Mammary Tumors and the Effects of Ovarian Follicular and Anterior Pituitary Hormones,” in American Journal of Cancer, 25 (1935), 291
Ruth Schwartz Cowan