Professional Profile

image for Hess, Rex A

Hess, Rex A

Professor Emeritus, Comparative Biosciences
2001 S. Lincoln Ave.
2001 S Lincoln
M/C 002
Urbana, IL  61802

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Honors, Awards University of Illinois

show listAcademic Positions

1986  Assistant Professor, Dept. of Veterinary Biosciences, University of Illinois

1986  Faculty Director of Microscopic Imaging Laboratory

1992  Adjunct Scientist; Yerkes Regional Primate Research Center, Emory University

1990  Affiliate; Institute for Environmental Studies, University of Illinois

1992  Associate Professor; Dept. of Veterinary Biosciences, University of Illinois

1995  Director of Center for Microscopic Imaging, University of Illinois

1998  Professor; Department of Veterinary Biosciences, University of Illinois

1998  Chair of Morphology Division, Department of Veterinary Biosciences

2005  Affiliate member, Institute for Genomic Biology, University of Illinois

2009  Professor Emeritus, Dept. of Comparative Biosciences, University of Illinois

2012  Visiting Professor, University of Missouri-Columbia, Bond Life Sciences Center


show listResearch Interests

Testicular growth and development, estrogen regulation of the male reproductive tract, spermatogonial stem cell regulation and the effects of gene disruption on spermatogenesis and efferent ductule structure and function.

show listEducation

B.S.        1971    Education/Zoology, Cum Laude, University of Missouri-Columbia

M.S.       1975    Physiology Area, University of Missouri-Columbia

Ph.D.      1983    Animal Physiology, Clemson University

Postdoc   1983-1986 Health Effects Research, U.S. Environmental Protection Agency, RTP, N.C.

show listBiography

Dr. Hess studied Zoology and Science Education for an undergraduate degree at the University of Missouri-Columbia with High Honors in 1971. While working full-time in Poultry Research and later as a technician in Electron Microscopy, he completed a Master's degree in Physiology at the University of Missouri-Columbia in 1975. Then he moved to Washington University School of Medicine in St. Louis, where he worked as an Electron Microscopy Associate until 1978. At Mount Sinai Medical School in New York City he worked in Pulmonary Medicine, but was later selected to study for the PhD at Clemson University in Animal Physiology, studying Reproductive Biology from 1980-1983. He did 3 years Postdoctoral training in Reproductive and Endocrine Toxicology at the US Environmental Protection Agency, in Research Triangle Park, NC. In 1986 he began his long career as a Professor at the University of Illinois, Urbana-Champaign, were he also served as the University Director of Center for Microscopic Imaging from 1995-2003; Director and PI of the NIEHS Training Grant in Environmental Toxicology from 1998-2002. Currently, as Professor Emeritus he teaches Cell and Tissue Biology at the Medical School and is active in several research collaborations on the effects of gene disruption in spermatogenesis and efferent ductule structure and function.

show listSelected Publications

Hess, R. A., D. Bunick, K. H. Lee, J. Bahr, J. A. Taylor, K. S. Korach and D. B. Lubahn (1997). "A role for oestrogens in the male reproductive system." Nature 390(6659): 509-512.

Hess, R.A., Sharpe, R.M., Hinton, B.T. (2021). Estrogens and development of the rete testis, efferent ductules, epididymis and vas deferens. Differentiation; research in biological diversity, (in press).

Hess RA and Cooke PS (2018). Estrogen in the male: a historical perspective. Biol Reprod. PMID: 29438493. Identifier: 10.1093/biolre/ioy043.

Nanjappa, M. K., R. A. Hess, T. I. Medrano, S. H. Locker, E. R. Levin and P. S. Cooke (2016). "Membrane-Localized Estrogen Receptor 1 is Required for Normal Male Reproductive Development and Function in Mice." Endocrinology: 157(7):2909-2919.

Cooke PS, Nanjappa MK, Ko C, Prins GS, Hess RA. (2017) Estrogens in Male Physiology. Physiol Rev. 97:995-1043.

Hess, R. A. (2018) Efferent ductules: structure and function. In: Encyclopedia of Reproduction. M. K. Skinner. San Diego, Academic Press: Elsevier.  2nd, 1: 48:   pp. 270-278.

Hess, R. A. (2018) Endocrinology and pathology of rete testis and efferent ductules. In: Encyclopedia of Reproduction. M. K. Skinner. San Diego, Academic Press: Elsevier.  2nd, 1: 49:   pp. 279–285.

Chen C, Ouyang W, Grigura V, Zhou Q, Carnes K, Lim H, Zhao GQ, Arber S, Kurpios N, Murphy TL, Cheng AM, Hassell JA, Chandrashekar V, Hofmann MC, Hess RA & Murphy KM. (2005) ERM is required for transcriptional control of the spermatogonial stem cell niche. Nature 436, 1030-1034.

Hess RA & de Franca LR. (2008) Spermatogenesis and cycle of the seminiferous epithelium. Adv Exp Med Biol 636, 1-15.

Hess RA & Vogl AW (2015) Sertoli cell anatomy and cytoskeleton. In: Sertoli Cell Biology (ed M Griswold), pp. 1-55. Elsevier Academic Press, Oxford.

Hess RA, Fernandes SA, Gomes GR, Oliveira CA, Lazari MF & Porto CS. (2011) Estrogen and its receptors in efferent ductules and epididymis. J Androl 32, 600-613.

Hess RA. (2014) Disruption of estrogen receptor signaling and similar pathways in the efferent ductules and initial segments of the epididymis. Spermatogenesis 4, e979103.

Danielian PS, Hess RA and Lees JA. (2016) E2f4 and E2f5 are essential for the development of the male reproductive system. Cell Cycle 15(2):250-260. PMID: 26825228. Identifier: 10.1080/15384101.2015.1121350.

show listSelected Service Activities

Invited International Lectures (selected from over 100, of which 55 were given in foreign countries):

Invited Lecture, “Efferent Ductules – A Ciliated Tubular Organ,” 7th International Conference on the Epididymis, Montreal, Canada. September 20-23, 2018.

Invited Lecture, “Proliferation of Sertoli Cells Revisited”, Symposium on Life History of Leydig and Sertoli Cells, 99th Annual Meeting of the Endocrine Society, Orlando, FL, April 1, 2017.

Invited Lecture, “The Efferent Ductules: Historical and Current Perspectives,” 5th Integrative Symposium of the Graduate Programs in Cell Biology and 8th Cell Biology Symposium from Universidade Federal de Minas Gerais, Belo Horizonte, Brazil. In honor of Prof. Cleida Aparecida De Oliveira. September 22, 2017.

Invited Lecture, "Small tubules, surprising discoveries: from efferent ductules in the turkey to the discovery that estrogen receptor alpha is essential for fertility in the male,” The V International Symposium on Animal Biology of Reproduction (ISABR 2014), Campinas, SP, Brazil, October 8-11, 2014. This meeting was dedicated to Dr. Rex Hess in tribute to his lifetime scientific contributions.

Invited Lecture, "Abnormalities and toxicity in the head of the epididymis: effects on testis and epididymal sperm,” Brazilian Congress of Animal Reproduction, Uberlândia, Minas Gerais State, Brazil, June 05 - 07, 2013.

Invited lecture, "Morphology shines a bright light on mechanisms of testicular toxicity: a tribute to Lonnie Russell,” IV International Symposium on Animal Biology of Reproduction, Campinas, São Paulo, Brazil, Oct 17-20, 2012.

Invited Lecture, “Estrogen and its Receptors in Efferent Ductules and Epididymis,” Fifth International Conference on the Epididymis, Águas de São Pedro, São Paulo, Brazil, on October 25-28, 2010.

Invited Lecture, “Estrogens and the male reproductive tract.” 1st International Symposium on Animal Biology of Reproduction: From Sex Differentiation to Reproductive Biotechnology. Belo Horizonte, Brazil. November 15-18, 2006.

Invited Lecture, “Estrogens/Xenoestrogens and their impact on the male reproductive system.” University Campus Zurich-Irchel, Winterthurerstr, Switzerland. June 30, 2005.

Invited Lecture, "Histopathological evaluation of the testis.” Graduate seminar in Molecular Veterinary medicine, University of Giessen, Germany. April 27, 2005.

Invited Speaker, “Male Fertility: Role of Oestrogens in Efferent Ductules and Epididymal Function.” AstraZeneca R&D, Alderley Park, Safety Assessment, Cheshire, England. March 18, 2005.

Invited Symposium Keynote Speaker, “Epididymal Toxicology,” 1stEuropean Congress of Toxicological Pathology, Hamburg, Germany, September 24-27, 2003.

Invited Speaker, “Estrogen importance in the male: from a curiosity to absolute necessity,” Department of Endocrinology and Cell Biology, University Medical Center Utrecht, The Netherlands, September 29, 2003.

Invited Speaker, “Estrogen importance in the male: from a curiosity to absolute necessity,” Mini-symposium at the Institute of Biological Sciences, Federal University, Belo Horizonte, Brazil. April 11, 2003.

Invited Speaker, “Estrogens and Efferent Ducts,” International Congress on Hormonal Steroids and Hormones and Cancer, Fukuoka City, Japan, October 21-25, 2002.

Invited Speaker, “Estrogen and male reproduction: source, target, function and potential effects of environmental estrogens,” University of Yokohama, Japan, October 28, 2002.

Invited lecture. “Estrogen regulates male fertility through ion transport mechanisms.” Dept. of Biochemistry, Università degli Studi di Bari, Bari, Italy. February 16-20, 2002.

Invited lecture, “A role for estrogens in the male reproductive system: the impact of xenoestrogens.” Gordon Research Conference on Environmental Endocrine Disruptors at Mt. Holyoke College in South Hadley, Massachusetts, July 14-19, 2002.

Invited lecture, “Estrogens and Fertility in the Male,” e.hormone 2001, Tulane University, New Orleans, LA. October 18-20.

Invited lecture, Workshop on Genomic vs. Non-Genomic Steroid Actions: Encountered or Unified Views. Centre for International Meetings on Biology, Juan March Institute for Study and Research, Madrid, Spain, 17-19 December, 2001.

Invited Speaker. “Estrogen and the male.” Monash Institute of Reproduction and Development, Prince Henry's Institute of Medical Research Melbourne, Victoria 3168 Australia. November 9, 2000.

Invited speaker, The Boden Research Conference 2000 on "Estrogens and Male Health,” Sponsored by the Australian academy of Science, the Australian Society of Reproductive Biology and Endocrine Society of Australia, November 2-3, 2000, in Sydney, NSW, Australia.

Invited speaker, Symposium on Estrogen and male reproduction. 1st European Congress of Andrology, March 24-27, 2000. L'Aquila, Italy.

Plenary Lecture, International Workshop, Estrogens and Male Reproduction, Crotone, Italy, Sept. 23-24, 1999.

Invited speaker, Estrogens and Male Reproduction, Federal University of Minas Gerais, Belo Horizonte, Brazil, Oct 12, 1999.

Invited speaker at the Gordon Research Conference on Reproductive Tract Biology, “Hormonal effects in the epididymis,” Plymouth State College, Plymouth, New Hampshire, July 5-10, 1998.

Invited seminar, “The role of estrogen in the male reproductive tract.” Institut für Reproduktionsmedizin, Westfälische Wilhems-Universität Münster, Germany. November 16, 1996.

Invited seminar, “Factors regulating testis size” Institut für Reproduktionsmedizin, Westfälische Wilhems-Universität Münster, Germany. November 15, 1996.

Invited seminar, “Use of the estrogen receptor knock-out transgenic mouse to study male reproduction” Universite de Rennes, Campus de Beaullou, Rennes, France. November 18, 1996.

Invited speaker at the United Nations University Symposium on Environment and Human Health, held at the University of Ulm, Federal Republic of Germany, March 4-8, 1990.

show listServices

Activities in Professional Societies

Memberships (current and past)

         Society for the Study of Reproduction (present)

         American Society of Andrology (present)

         The Endocrine Society (present)

         International Society for Stem Cell Research

         Society of Toxicology (present)

         Microscopy Society of America

Offices Held

         1979-1980Treasurer, Central-States Electron Microscopy Society

         1995-1998Secretary, American Society of Andrology

         2011-2014 Treasurer, American Society of Andrology

         2014-2017 Treasurer, American Society of Andrology

Editorial Boards (past and present service)

Domestic Animal Endocrinology, Published by Elsevier Science, Inc.

Journal of Andrology, Published by American Society of Andrology

Tissue and Cell

Reproductive Biology & Endocrinology, by BioMed Central

Biology of Reproduction

Animal Reproduction

Physiological Reviews

Public Service

President of the Champaign Chapter of the International Lion's Club (2009)

Review of Manuscripts for more than 50 different Scientific Journals over the past 30 years

Vice-President of the Harlan E. Moore Heart Research Foundation (2002-2008)


show listCourses Taught

Veterinary Histology

Medical Histology and Cell Biology

Basic Toxicology (the Reproductive Toxicology section)

Developmental Anatomy

Discovery in Environmental Toxicology

Morphology of Reproduction

Integrated Electron Microscopy

Toxicologic Pathology (the Male Reproductive Toxicology section)

Interdisciplinary Toxicology Seminar

General Animal Physiology