The penis: a new target and source of estrogen in male reproduction
C.N. Mowa1, S. Jesmin2 and T. Miyauchi2
1Department of Biology, Appalachian State Univesity, Boone, NC, USA and 2Tsukuba University, Department of Cardiovascular Medicine, Tsukuba, Japan
Offprint requests to: Dr. Chishimba Nathan Mowa, Department of Biology, Appalachian State University, PO Box 32027, 572 River St, Rankin Science North Bldg Rm N219, Boone, NC 28607, USA. e-mail: chishimba@lycos.com
Summary. In the past decade, interest and knowledge in the role of estrogen in male reproduction and fertility has gained significant momentum. More recently, the cellular distribution and activity of estrogen receptors (alpha and ß)(ER) and aromatase (estrogen synthesis) has been reported in the penis, making the penis the latest “frontier” in the study of estrogen in male reproduction. ER and aromatase are broadly and abundantly expressed in various penile compartments and cell types (erectile tissues, urethral epithelia, vascular and neuronal cells), suggesting the complexity and significance of the estrogen-ER system in penile events. Unraveling this complexity is important and will require utilization of the various resources that are now at our disposal including, animal models and human lacking or deficient in ER and aromatase and the use of advanced and sensitive techniques. Some of the obvious areas that require our attention include: 1) a comprehensive mapping of ER-alpha and -ß cellular expression in the different penile compartments and subpopulations of cells, 2) delineation of the specific roles of estrogen in the different subpopulations of cells, 3) establishing the relationship of the estrogen-ER system with the androgen-androgen receptor system, if any, and 4) characterizing the specific penile phenotypes in human and animals lacking or deficient in estrogen and ER. Some data generated thus far, although preliminary, appear to challenge the long held dogma that, overall, androgens have a regulatory monopoly of penile development and function. Histol Histopathol 21, 53-67 (2006)
Key words: Penis, ER, Aromatase, Estrogen
DOI: 10.14670/HH-21.53