Submission Number: GER-4-12-13

Abstract Number: 321

DEVELOPMENTAL EXPRESSION OF ESTROGEN RECEPTOR AND IN THE BABOON FETAL OVARY.

Gerald J Pepe* ¹, Reinhart B Billiar* ¹, Maria G Leavitt ¹ and Eugene D Albrecht* ²

Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA ¹
Departments of Obstetrics/Gynecology/Reproductive Sciences and Physiology, The Center for Studies in Reproduction, University of Maryland School of Medicine, Baltimore, MD ²

Abstract:
In adult mammals, estrogen regulates ovarian function and estrogen receptor (ER) is expressed in granulosa cells of antral follicles of the adult baboon ovary. Because the foundation of adult ovarian function is established in utero, the present study determined whether ER and/or ER were expressed in fetal ovaries obtained on days 60 (n=1), 100 (n=3) and 165-180 (n=5) of baboon gestation (term = day 184). ER protein was detected by immunocytochemistry as early as day 60 of gestation in surface epithelium and mesenchymal-epithelial cells as well as in germ cell cords at day 100. At days 165-180 of gestation, ER expression was still intense in the surface epithelium, in mesenchymal-epithelial cells throughout the cortex and in nests of cells between follicles. ER expression was lighter in granulosa cells and not observed in all granulosa cells particularly in follicles close to the cortex. In contrast, ER expression was most intense in granulosa cells, especially in flattened granulosa, weak or absent in epithelial cells and nests of cells between follicles and absent in the surface epithelium. Using an antibody to the carboxy terminal of human ER, ER protein was also detected by Western blot with a molecular size of 55 and 63 kDa at day 100 and primarily 55 kDa at day 180. The mRNAs for ER and ER were also detected by Northern blot analysis in the baboon fetal ovary. These results are the first to establish that the ER and ER mRNAs and proteins are expressed in the primate fetal ovary between mid and late gestation. Because placental estrogen production and secretion into the baboon fetus increases markedly during advancing pregnancy, we propose that estrogen plays an integral role in programming fetal ovarian development in the primate. Supported by NIH NICHD HD 36207 Specialized Cooperative Centers Program in Reproduction Research.

Keywords: estrogen receptor alpha, estrogen receptor beta, fetal ovary, baboon

This abstract is being presented at: 8:00 AM in session:
Gonadal Function