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Michael P. McGuinness1 , DoWon Hahn1 *
RWJohnson Pharmaceutical Research Institute, Raritan, New Jersey 1
Estrogen is crucial for the maintenance of spermatogenesis. Estrogen receptors (ER) are present in Sertoli and Leydig cells. However, the function of estrogen in these cells is unknown. ASC17D/Sertoli and TM3/Leydig cell lines were used to characterize the effect of estrogen in testis. ERa was detected in cell lysates from ASC17D and TM3 cells by Western blot analysis. ER was not detected. The effect of 17-estradiol (E, 10 nM) on proliferation of these cells was examined. In TM3, E inhibited proliferation by day 6 of culture. 17a-estradiol (17a), ethinylestradiol (EE) and diethylstilbestrol (DES) (10 nM each) also inhibited cell division while raloxifene (Ral) and tamoxifen (Tam) had no effect. An estrogen antagonist (ICI 182,780 [ICI]) was able to block the effect of E on proliferation of TM3 cells. ASC17D cells responded differently to these treatments. 17a, E, EE and DES did not alter proliferation of ASC17D. However, Ral, Tam, and ICI inhibited proliferation. E did not block this inhibition. Thus, Ral, Tam and ICI may act through a pathway which does not involve the estrogen receptor. Levels of mRNA for TGF1&2 and IL-6 which are known to be regulated by E and alter proliferation in other tissues were not altered by E in either cell line. To facilitate the identification of estrogen regulated genes in TM3 cells, mRNA differential display and Northern blot analysis was used. Two E-regulated mRNAs have been identified. TM3-15 (1.0 kb mRNA) was down regulated (2.1 fold) by E while TM3-20 (3.0 kb mRNA) was upregulated (2.8 fold). Homologous sequences were not found in GenBank. In summary, we have expanded our knowledge of how estrogens influence cell division and begun to characterize E regulated genes in testis. These data are part of ongoing studies to characterize how estrogens influence spermatogenesis.
This abstract is being presented on Monday, August 2 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.