Cytochrome p450 aromatase in testis and epididymis of male rhesus monkeys

A. C. Pereyra-Martinez, Charles Roselli, H. L. Stadelman, J. A. Resko

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To understand the role of estrogen in testicular and epididymal function of rhesus monkeys, we measured steroids in the spermatic and peripheral venus circulation and aromatase activity and its mRNA in testis and epididymis. Testosterone, estradiol-17β,and estrone, but not androstenedione, were elevated in the spermatic vein serum compared to the peripheral circulation. Aromatase activity in testis and in caput epididymis (259 ± 16 [SEM] vs 274 ± 47 fmol of 3H 2O/mg of protein/h [n = 10], respectively) was significantly higher (p <0.01) than in corpus and cauda (124 ± 28 and 113 ± 33 fmol of 3H 2O/mg of protein/h [n = 10], respectively). In the ribonuclease protection assay, two P450 arom mRNA transcripts were identified in testis and epididymis. One corresponded with the aromatase full-length transcript and the other was a truncated isoform. The latter was significantly more abundant than the former (p <0.01). Our results demonstrate that the monkey testis and, to a lesser extent, the epididymis can aromatize androgens. However, in the epididymis, like in some areas of the brain, there was a discrepancy between the aromatase activity and the mRNA. The fact that P450 arom mRNA and aromatase activity do not correlate in the epididymis may indicate that aromatase activity is not strictly regulated at the level of RNA expression and that other mechanisms for this regulation should be considered.

Original languageEnglish (US)
Pages (from-to)15-19
Number of pages5
Issue number1
Publication statusPublished - 2001
Externally publishedYes



  • Aromatase
  • Epididymis
  • Messenger RNA
  • Rhesus monkey
  • Testis

ASJC Scopus subject areas

  • Endocrinology

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