Department of Obstetrics and Gynecology (K.N., K.S., R.B., A.R.), Department of Pathology (R.B., A.R.), and Childrens Hospital (I.K., M.H.), Helsinki University Central Hospital and Haartman Institute, University of Helsinki, Finland; Department of Pediatrics (M.H.), Washington University, St. Louis, Missouri
Prostaglandins (PGs) have been implicated in regulation of ovarian
function. We have previously shown that the expression of
cyclooxygenase-2 and the receptor for PGF2 are
expressed in periovulatory human granulosa cells and upregulated by
gonadotropins and cytokines in cultured human ovarian granulosa-luteal
(GL) cells. We now show that transcripts for PGE2 receptor
subtypes EP2 and EP4 are expressed in freshly isolated human granulosa
cells and in mouse ovaries as detected by Northern blot analysis.
However, EP2 and EP4 receptor mRNA levels were low or nondetectable in
cultured human GL cells suggesting that these transcripts may be under
hormonal and/or cytokine regulation in the ovaries in vivo.
Indeed, the proinflammatory cytokine interleukin-1ß (IL-1ß)
stimulated expression of EP2 and EP4 transcripts in concentration- and
time-dependent manner in the GL cells. Furthermore, the transcript for
EP2 receptor was localized in the corpus luteum of the mouse ovary by
in situ hybridization, and EP2 protein was expressed in
human corpus luteum as detected by immunohistochemistry. Our data
suggest that IL-1ß induces expression of EP2 and EP4 receptors in
human GL cells, and that EP2 receptor is expressed in both human and
murine luteal glands.