PARENT SESSION
PLATFORM SESSION 11: MOLECULAR MECHANISMS OF HORMONE ACTION
Chair: Nilson, John¹, ¹
Co-chair: Horvat, Regina¹, ¹
Grand Ballroom I-IV
2:00 PM-4:00 PM

(228) ESTROGEN RECEPTOR (ER) AND ER- STIMULATION INCREASES VASCULAR ENDOTHELIAL GROWTH FACTOR SECRETION BY OVINE UTERINE ARTERY ENDOTHELIAL CELLS.

King, Adam¹, Zheng, Jing¹, Bird, Ian¹, Magness, Ronald^1,2, ¹ Perinatal Research Labs, Madison, WI² Dept of Animal Science, Madison, WI

ABSTRACT- The follicular phase of the ovarian cycle and pregnancy are physiologic states when estrogen levels (E2B), uterine angiogenesis, and uterine vascular permeability are increased. Vascular Endothelial Growth Factor (VEGF) is a potent regulator of both angiogenesis and vascular permeability. Thus, estrogen may modulate angiogenic growth factors (e.g.VEGF) within uterine vascular bed. We have reported that the in vivo expression of VEGF is elevated in the uterine vascular endothelium during the follicular phase and with E2B treatment of sheep. Therefore we hypothesize that E2B will have direct effects to increase the secretion and expression of VEGF by the uterine vascular endothelium in vitro. Method: Ovine uterine artery endothelial cells (UAEC) from were grown in MEM with 2% FBS/18% charcoal stripped serum and treated for 24hrs with or without E2B (0.1, 1.0, 5.0, 10, or 100 nM) and ICI-182,780 (ICI; 2.0 mM) the ER selective antagonist. Selective agonists for both ER- (16-iodo-17B-E2B; 0.1 nM), and ER-B (Genestein; 10 nM), were also studied. Secreted VEGF protein was quantified in cell culture media via ELISA, and cell-associated VEGF was quantified via Western analysis. Results: In response to E2B, VEGF secreted into culture media by UAEC was dose dependently increased with a maximum responses of 3-4 fold at 10nM (P< 0.001), while cellular-associated VEGF was unchanged at all doses of E2B studied. Similarly, both 16-iodo-17B-E2B and Genestein stimulated increased secretion of VEGF, but not cell-associated VEGF. VEGF secretion by UAEC in response to E2B was completely blocked by ICI. Conclusion: E2B dramatically increases the secretion of VEGF by UAEC via an ER-mediated mechanism. This response appears to be acting through both ER- and/or ER-B since specific ER- and ER-B agonists increased VEGF secretion. Therefore, E2B appears to signal UAEC to secrete VEGF, which is likely to be a primary autocrine activator/modulator of vascular bed proliferation and permeability in the uterus during physiologic states of high estrogen. Supported by NIH grants HL49210, HD38843, HD33255, HL57653, HL64703, & HL64601.

KEY WORDS: Estrogen Receptor, Angiogenesis, Vascular Endothelial Growth Factor, Uterus