Although synthesis of estrogen by male gonads has been well documented for over half a century, it is only recently that the role of estrogen in male reproductive events has gained appreciation. We recently reported abundant expression of ER-alpha and -beta in perinatal rat penis, whose levels diminished with advancing age. The present study investigates whether the penis is capable of synthesizing its own estrogen by examining presence of aromtase, the microsomal enzymatic complex which irreversibly converts androgens to estrogens, using immunohistochemistry, Western blotting, in situ hybridization and real-time PCR analyses. Discrete aromatase immunoreactive (ir) cells were localized in primodial corpus cavernosus, spongiosus and os penis, blood vessels and sensory corpuscles of glans penis, corresponding with the expression pattern of ERs. In situ hybridization signals, though diffuse, matched those of immunohistochemistry. Western blot an real-time analyses of penile samples from 1, 8, 35 week-old rats revealed an age-dependent expression, with levels of aromatase at week 1 almost matching those of adult ovary, but decreasing sharply by week 8 and, decreased further by week 35. This expression pattern was strikingly similar to that of ER-alpha reported previously. We conclude that the penile tissue produces its own estrogen, which may play a role in regulating penile events in an autocrine/paracrine manner.
03 - 05 Nov 2003
Society for Endocrinology