Mol. Hum. Reprod. Advance Access originally published online on October 11, 2005
Molecular Human Reproduction 2005 11(9):615-621; doi:10.1093/molehr/gah215
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Characterization of 17ß-hydroxysteroid dehydrogenase type 4 in human ovarian surface epithelial cells
1Department of Reproductive Medicine and Surgery, 2Department of Molecular Pharmacology and 3Department of Gynecology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
4 To whom correspondence should be addressed at: Department of Reproductive Medicine and Surgery, Graduate School of Medical Sciences, Kumamoto University, Honjo 1-1-1, Kumamoto 860-8556, Japan. E-mail: yumikonagayoshi{at}fc.kuh.kumamoto-u.ac.jp
The human ovarian surface epithelium (hOSE) is a single layer of mesothelial-type primitive epithelial cells that are potential estrogen targets. It has been reported that hOSE cells can produce estrogen. However, the mechanisms that regulate estrogen level(s) in hOSE cells are not yet known. To elucidate the enzymes involved in these reactions, we examined gene expression of 17ß-hydroxysteroid dehydrogenases (17ß-HSDs) in primary hOSE (POSE) and OSE2a cells using RTPCR. We found that POSE cells and cells of the immortalized hOSE line, OSE2a, bidirectionally converted estrone (E1) and 17ß-estradiol (E2). Both cell types expressed mRNA for 17ß-HSD type 1 (17ß-HSD1), suggesting that the enzyme is involved in the E1 to E2 conversion. Interestingly, both cells expressed 17ß-HSD4 mRNA but not 17ß-HSD2 mRNA. We prepared an antibody against the carboxyl terminal of 17ß-HSD4 (anti-17ß-HSD4 antibody), which recognized the 80 and 48 kDa proteins in POSE and OSE2a cells based on immunoblot analysis. Furthermore, immunohistochemical study revealed the presence of 17ß-HSD4 in hOSE cells in the human ovary. These results suggest that 17ß-HSD4 is involved in estrogen inactivation and may protect against an excessive accumulation of E2 in hOSE cells.
Key words: estrogen/ovarian surface epithelial cells/ovary/17ß-HSD4