Table 1-1. CHRONOLOGY OF LANDMARK EVENTS

Dates								Key Investigators

340 BC		Generation of Animals				Aristotle
300 BC		Discovery of ovaries, pineal gland			Herophilus
1561		Description of oviducts				Fallopius
1672		Depiction of seminiferous tubule, follicle, CL		de Graaf
1678		Microscopic observation of seminal spermatozoa		van Leeuwenhoek
1759		Epigenics; embryonic origin of male ducts			Wolff
1782		Artificial insemination					Spallanzani
1786		Testicular regulation of male accessory glands		Hunter
1824-27		Fertilizing capability of spermatozoa			Prévost, Dumas
1827		Discovery of the ovum				von Baer
1830		Embryology of female duct system			Müller
1838		Embryonic origin of the adenohypophysis			Rathke
1843		Report of sperm penetration of mammalian ova		Barry
1849		Androgenizing effects of testis				Berthold
1850		Description of testicular interstitial cells			von Leydig
1865		Description of seminiferous epithelium			Sertoli
1883		Haploid nature of gametes				van Beneden
1890		Embryo transfer (rabbit)				Heape
1891		Embryo splitting (echinoderm)				Driesch
1895		Origin of CL					Sobotta
1897		Role of epididymis in sperm maturation			Hammar
1900-10		Ovarian regulation of the uterus				Knauer, Fraenkel, Ancel, Bouin
1900/40s		Pioneering studies of ovarian cycles			Heape, Marshall, Hammond, Hartman, Asdell
1901		Genetic determination of sex				McClung
1903		Male hormone produced by Leydig cells			Bouin, Ancel
1905		Endocrine function of placenta				Halban
1906		Uterotonic action of oxytocin				Dale*
		Concept of ligand-receptor binding			Langley, Ehrlich*
1911-23		Ovulation-inhibiting effect of luteal extracts			Loeb, Haberlandt
1912		Gonadal atrophy following hypophysectomy		Aschner
1917		Vaginal smear					Stockard, Papanicolaou
1922		Detailed description of rat estrous cycle			Long, Evans
1922-30		Thermoregulation of spermatogenesis			Crew, Walton
1923		Effect of hysterectomy on luteal function			Loeb
1920/30s		Characterizations of gonadal steroid hormones		Allen, Butenandt*, Corner, Doisy*, Koch, Marrian, Laqueur
		Commercial application of AI to livestock			Ivanoff, Milovanov
1926		Discovery of relaxin					Hisaw
1927		Discovery of hCG					Aschheim, Zondek
		Parapharyngeal hypophysectomy			Smith
1928		Discovery of prolactin				Stricker, Grueter
1929		Pituitary involvement in reflex ovulation			Fee, Parkes
1930		Discovery of PMSG					Cole, Hart
		Description of hypophyseal portal vessels			Popa, Fielding
1930s		Discovery of prostaglandins				Kurzok, Lieb, Goldblatt, von Euler*
		Delineation of menstrual ovulatory phase			Hartman
1931		Recognition of distinct pituitary gonadotropins		Fevold
1932		Pituitary feedback via sex steroids			Moore, Price
		Postulated existence of inhibin				McCullagh
		Isolation of urinary estrogens				Girard
1933		Prolactin bioassay					Riddle, Bates
1935-36		Studies of hypophyseal portal blood flow			Houssay*, Wislocki, King
1936		Gonadotropic control of testis				Greep
1937		Positive feedback effect of estradiol			Hohlweg
1940		Semen preservation					Phillips, Lardy
1940s		Prostatic pathology/secretions				Huggins*
1940/50s		Evidence for anti-Mullerian hormone			Jost
1940/60s		Spermatogenesis/sperm anatomy			Ortavant, Clermont, Fawcett
		Development of neuroendocrinology			Hinsey, Markee, Everett, Sawyer
1941		Luteotropic role of prolactin				Astwood
		Prostate bioassay for LH (androgens)			Greep
 		Anesthetic effect of steroid hormones			Selye
1944		In vitro fertilization of a human ovum			Rock, Menkin
1947		Neurovascular control of pituitary gland			Green, Harris
1948		Control of bacterial growth in semen			Almquist
1949		Discovery of sex chromatin				Barr
		Analysis of ligand-binding data				Scatchard
		Cryoprotection of sperm cells				Polge
1950s		Formulation of oral contraceptives			Pincus, Chang, Colton, Djerassi
1951		Capacitation of sperm				Austin, Chang
1953		Bioassay for FSH					Steelman, Pohley
		Structure of oxytocin					du Vigneaud*
1958		Discovery of cAMP					Sutherland*
		Isolation of melatonin				Lerner
1959		Advent of radioimmunoassay				Yalow*, Berson
		Purification of LH					Li
		Male-determining role of mammalian Y chromosome		Welshons, Russell
1960s		Hypothalamic control of prolactin secretion		Meites
		Isolation of cAMP-dependent protein kinases		Krebs*
1961		Ovarian ascorbate bioassay for LH			Parlow
1960/70s		Characterization of arachidonate metabolites		Bergstrom*, Samuellson*, Vane*
		Photoperiodic control of melatonin/reproduction		Quay, Reiter, Wurtman
		Structure/function of GnRH				McCann, Schally*, Guillemin*
		Biochemistry of seminal plasma				Mann, Williams-Ashman
1960/90s		Mechanisms of steroid hormone action			Mueller, Jensen, Gorski, Baulieu, Szego, O'Malley
1967		Subunit nature of gonadotropins			Papkoff
1968		Isolation of dihydrotestosterone				Wilson
1969		Luteolytic effect of PGF2α				Pharris
1970		Episodic pattern of hormone secretions			Knobil
1970s		Utero-ovarian vascular relationships			Ginther
		Purification of relaxin					Sherwood, Schwabe
1978		Birth of first test-tube baby				Steptoe, Edwards*
1970/80s		Role of G-proteins in membrane receptor actions		Rodbell*, Gilman*
1980s		Transgenic animals					Gordon, Ruddle, Brinster
1984		Purification of MIH					Josso
1985		Purification of inhibin					de Kretser, Miyamoto, Vale, Guillemin*
1988		Structure of prolactin receptor				Kelly
1989		Genetic screening of human embryos			Handyside
1989-90		Structure of LH and FSH receptors			Segaloff
1990		Isolation of sex-determining region of Y gene		Lovell-Badge, Goodfellow
1992		Structure of GnRH receptor				Sealfon
		Structure of oxytocin receptor				Kimura
1993		Human embryos cloned (six-cell stage)			Hall, Stillman
1997		Sheep cloned from a nonembryonic cell			Wilmut

*Nobel laureates.