- Email: [email protected]
Subendometrial vascularization and in vitro fertilization outcomes
Subjects with male factor infertility as a sole diagnosis were used as controls. Endometrial growth curves were plotted and compared. T test was used to compare peak endometrial thickness. Paired T test was used to compare peak endometrial thickness in subjects with multiple treatment cycles. Linear regression analysis was used to determine the effects of multiple variables on endometrial growth. RESULTS: A sigmoidal pattern of endometrial growth was observed. Growth began after a nadir of 4.5 mm on day 4, reached a peak of 9 mm at day 9 and then plateaued. This time course and pattern of growth was observed in all treatment groups and diagnoses, although the plateau thickness on day 9 varied. Patients treated with FSH achieved a higher plateau (10.7 mm) than those treated with clomiphene citrate (8.6 mm (P<0.001)). Patients with PCOS, endometriosis, and recurrent pregnancy loss (RPL) each plateaued at a lower thickness than controls. The mean endometrial thickness in the control group was 11.2 mm, compared to PCOS: 8.9 mm (P<0.001), endometriosis: 9.3 mm (P¼0.015), and RPL: 9.3 mm (P¼0.010). Age, BMI, and maximum estradiol positively affected endometrial thickness [coefficient: 0.107 (P¼0.002), 0.0625 (P¼0.024), 0.000864 (P<0.001), respectively], while cycle day 3 FSH did not affect thickness [coefficient 0.0319 (P¼0.550)]. CONCLUSIONS: We characterized proliferative phase endometrial growth that followed a sigmoidal pattern and plateaued on cycle day 9. We identified a novel proliferative phase defect. Subjects and controls both demonstrated a similar nadir, growth duration and pattern, however this defect was distinguished by lower peak and plateau endometrial thickness. These results suggest that proliferative phase endometrial growth deficiency may be a common abnormality in women with infertility and RPL. Supported by: None.
between luteal serum progesterone levels and the occurrence of pregnancy following ovulation induction (OI). DESIGN: Retrospective analysis of 1554 cycles from patients with oligoanovulatory infertility and/or amenorrhea (WHO II classification). MATERIALS AND METHODS: Inclusion criteria for the analysis were: one or two progesterone levels in the mid-luteal phase, one between days 5 to 7 and the second between days 8 to 10 post hCG (the higher of the two levels was used for statistical analysis) and complete data on the outcome of the cycle. The primary endpoint for all studies was ovulation. All patients included were treated with FSH using a step up protocol. RESULTS: Baseline demographic characteristics for the population were: mean age of 30.1 3.7 (range 19–39) and mean BMI of 24.8 4.8 (range 16–37). Overall, out of 1554 cycles, 346 achieved a pregnancy (22.3%); 295 of them were clinical pregnancies (19.0%) and 51 had a biochemical pregnancy (3.3%). Live birth rate was 16.6% (258/1154). 87.5% of the clinical pregnancies led to live births. The relationship between clinical and biochemical pregnancy rates and live birth rates vs. progesterone levels is shown on Figure 1. Clinical pregnancy rates in cycles with progesterone levels above 10 ng/mL was 22.1%; 12.0% with progesterone levels between 5 and 10 ng/ml and 3.4% with levels less than 5 ng/mL. There was no relationship between progesterone levels and the occurrence of biochemical pregnancies.
P-262 THE ROLE OF BONE MORPHOGENETIC PROTEIN-7 (BMP-7) IN THE HUMAN ENDOMETRIUM. O. Yoshino, Y. Osuga, T. Yano, Y. Taketani. Obstetrics and Gynecology, Tokyo University, Bunkyo-ku, Tokyo, Japan. OBJECTIVE: Bone morphogenetic proteins (BMPs) play critical roles in cellular differentiation in multiple tissues. Among BMPs, it is reported that BMP-7 is expressed in the endometrium. In the endometrium, the differentiation process is occurred at secretory phase as decidualization of endometrial cells for successful implantation and pregnancy. We analyzed the role of BMP-7 in the human endometrium, focusing on decidualization. DESIGN: Experimental study using human endometrial cells. MATERIALS AND METHODS: Informed consent for tissue sampling was obtained from each patient. Endometrial tissues were obtained from the patients who underwent operation for benign diseases. The mRNA expression of BMP-7 in the endometrium was analyzed by quantitative reverse transcription-polymerase chain reaction (RT-PCR, n ¼ 24). Endometrial epithelial and stromal cells were cultured separately followed by checking BMP-7 mRNA. In vitro decidualization of stromal cells were induced with estradiol (E: 10 ng/ml) and progesterone (P: 100 ng/ml) for up to 12 days culture. Recombinant BMP-7 (10–100 ng/ml) was added to this culture system, followed by measuring prolactin concentration in the supernatant. RESULTS: The quantitative RT-PCR analyses showed that BMP-7 mRNA was diminished significantly in the late secretory phase compared to other phases. The BMP-7 mRNA was detected in epithelial and stromal cells. With 6 days of EP treatment, cultured stromal cells started secretion of a differentiation marker, prolactin. But in the presence of BMP-7, prolactin concentration decreased to undetectable level. After 12 days incubation with EP and BMP-7, prolactin concentration was decreased at BMP-7 dose-dependent manner and decreased by 60% with 100 ng/ml BMP-7. CONCLUSIONS: In vitro study showed that BMP-7 has a potential to inhibit endometrial cells differentiation. The attenuation of BMP-7 mRNA expression in the late secretory phase might be one of the mechanisms to induce endometrial cells differentiation. Supported by: Japan Society for the Promotion of Science. P-263 CORRELATION BETWEEN LUTEAL SERUM PROGESTERONE LEVELS AND PREGNANCY IN OVULATION INDUCTION. D. R. Tredway, D. W. Warne, A. Eshkol, V. Alam. EMD Serono, Inc., Rockland, MA; MERCK Serono, Geneva, Switzerland. OBJECTIVE: Progesterone levels are commonly used for assessment of ovulation during clinical trials. This analysis evaluates the correlation
FERTILITY & STERILITYÒ
Figure
CONCLUSIONS: The probability of achieving a clinical pregnancy is correlated with progesterone levels above 5 ng/mL. With a luteal progesterone level above 20 ng/mL, a 28% clinical pregnancy rate was achieved of which 88% resulted in live births. Supported by: All clinical studies were conducted by Serono. P-264 SUBENDOMETRIAL VASCULARIZATION AND IN VITRO FERTILIZATION OUTCOMES. M. Scioscia, F. Lorusso, M. Palmisano, G. Serratı`, G. Lamanna, R. Depalo. Department of Gynecology, Obstetrics and Neonatology, University of Medical Science of Bari, Bari, Italy. OBJECTIVE: To evaluate changes in subendometrial vascularization during IVF cycles and to prospectively analyze whether ultrasonographic measurements of power Doppler areas predict IVF outcomes. DESIGN: Prospective analysis in a tertiary center for assisted reproduction. MATERIALS AND METHODS: Serial transvaginal scans were performed in a single cycle of 48 women undergoing IVF treatment. Subendometrial vascularization was determined by power Doppler ultrasonography on the day of hCG administration, and immediately before pick up and embryo transfer. Ultrasound evaluations were performed by a single operator using fixed power Doppler settings. A longitudinal view of the uterus was obtained and the Doppler box placed over the thickest part of the endometrium. All vascular areas were measured on a single frozen section and recorded as areas (mm2) and in a semiquantitative scale (<3, 3–6, 6.1–9, >9 mm). Ultrasonographic parameters and conception rates were considered for the analysis. RESULTS: Clinical pregnancy rate/cycle and the implantation rate were 25% and 11.8%, respectively. Endometrial thickness was similar among groups. Subendometrial vascularization areas were significantly larger in
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patients who achieved an ongoing pregnancy than in those women with nonconceptional cycles (190.6 35.2 mm2 vs. 323.7 43.5 mm2; P<0.001). Maternal age was inversely correlated with subendometrial vascularization at embryo transfer (r2 ¼ 0.29; P<0.1). CONCLUSIONS: Increasing patient age is associated with lower subendometrial vascularization and implantation rate, regardless endometrial thickness. These findings may help at understanding the decreasing endometrial receptivity as woman age progresses. Furthermore, sonographic evidence of poor vascularization may allow early prediction of a nonreceptive endometrium providing information about whether to perform the embryo transfer or to cryopreserve the embryos until endometrium is receptive during a next cycle. Supported by: None. P-265 INDIAN HEDGEHOG AND ITS ASSOCIATED DOWN-STREAM TARGETS ARE ALTERED IN RESPONSE TO IN VIVO CDB-2914 ADMINISTRATION. E. D. Levens, Q. Wei, L. K. Nieman. Reproductive Biology and Medicine Branch, National Institute of Child Health and Human Development, NIH, Bethesda, MD; Combined Federal Fellowship in Reproductive Endocrinology and Infertility at the National Institutes of Health, Walter Reed Army Medical Center, National Naval Medical Center, and Uniformed Services University of the Health Sciences, Bethesda, MD.
tive Endocrinology and Infertility, University of North Carolina, Chapel Hill, NC; Molecular and Integrative Physiology, University of Illinois at UrbanaChampaign, Urbana, IL. OBJECTIVE: The transcription factor CCAAT/enhancer-binding protein b (C/EBPb) is a critical mediator of murine endometrial epithelial and stromal cell proliferation and differentiation. Consequently, female mice lacking the C/EBPb gene are infertile. Previous studies have demonstrated the presence of C/EBPb mRNA in human endometrium and upregulation of C/EBPb during in vitro stromal decidualization. In order to further define the role of C/EBPb in human endometrium, we characterized temporal changes in C/ EBPb mRNA abundance over the normal human menstrual cycle. DESIGN: Laboratory analysis. MATERIALS AND METHODS: Volunteers (ages 18–35) were randomized to undergo endometrial sampling on a specific cycle day, and luteal phase samples were timed using the patient’s urinary luteinizing hormone (LH) surge. Real-time RT-PCR was performed on total RNA, in triplicate, using probe-primer sets specific for C/EBPb and the constitutively-expressed gene, PPIA. The data were grouped by cycle phase and analyzed by one way analysis of variance. Endometrial histology confirmed LH dating. RESULTS: Of the 50 samples obtained, 23, 6, 15, and 6 samples were in the proliferative, early secretory, midsecretory, and late secretory phases, respectively. C/EBPb mRNA expression was highest in the early and late secretory phases and lowest in the midsecretory phase. The relative difference between midsecretory and late secretory expression was 4-fold.
OBJECTIVE: Acting via its receptor (PR), progesterone (P4) rapidly induces Indian hedgehog (IHH) in the mouse and thus stimulates endometrial cell proliferation and differentiation via downstream targets (Smo, Ptc-1, Gli1, and Gli2). CDB-2914 (CDB), a selective P4 modulator, binds and occupies both PRA and PRB at higher affinity than P4. Having confirmed differential expression of Ihh in CDB treated human endometrium, our objective was to determine whether Ihh signaling was also affected. DESIGN: Human genome array, real-time RT PCR (RT-PCR) and immunohistochemistry (IHC). MATERIALS AND METHODS: After IRB approval, pre-menopausal patients received CDB (10 or 20 mg; n ¼ 8) or placebo (n ¼ 6) for 90 days before hysterectomy for symptomatic leiomyomata. No other hormonal therapy was given. Endometrium was obtained at surgery from proliferative (n ¼ 10) and secretory (n ¼ 3) phases as determined by histology. Total RNA was isolated and subjected to RT-PCR. IHC was performed using a goat anti-human Ihh polyclonal antibody (sc-1196). Staining intensity was evaluated using semi-quantitative H-scores. Proliferative phase endometrium was analyzed using Wilcoxon rank sum test; P<0.05 was considered significant. RESULTS: RT-PCR validated Ihh expression and the expression of genes involved in its signaling: Smo, Ptc, Gli1 and Gli2. CDB treatment significantly up-regulated Ihh and Gli1 but did not affect Smo, Ptc and Gli2 (figure). IHC revealed increased Ihh staining intensity in both endometrial glands and stroma in response to CDB (P¼0.015).
Figure
Figure
CONCLUSIONS: Ihh may be an important pathway by which progesterone signals in human endometrium. These results for the first time demonstrate altered Ihh signaling pathways due to long-term treatment with CDB-2914. Since these gene products have been implicated in cellular growth and differentiation, this pathway may be an integral regulatory mechanism of human endometrial function. Supported by: This research was supported by the intramural program of NICHD, NIH, Bethesda, MD, and by HRA Pharma, Paris, France. P-266 CYCLIC REGULATION OF TRANSCRIPTION FACTOR C/EBP IN HUMAN ENDOMETRIUM. B. J. Plante, M. K. Bagchi, L. Yuan, M. A. Fritz, S. L. Young. Obstetrics and Gynecology/Division of Reproduc-
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Abstracts
CONCLUSIONS: C/EBPb mRNA expression by whole endometrium peaks in the early and late secretory phases. The increase in the late secretory phase is predominantly due to marked increases at 13 and 14 days after the LH surge, suggesting that C/EBPb may play a role in preparing for menstruation. The finding of a nadir in C/EBPb expression during the midsecretory phase is surprising since ‘‘predecidualization’’ begins during this phase and C/EBPb plays a key role in murine endometrial decidualization. At present, the changes of expression in each cell type remain unclear, but ongoing experiments using in situ hybridization and immunohistochemistry will clarify changes in C/EBPb expression by specific cell types in human endometrium. Supported by: NICHD U54 HD035041–11 and the UNC Nova Carta Foundation. P-267 ESTROGEN-RESPONSIVE GENE EXPRESSION IN THE ENDOMETRIUM. L. Li, K. Tatsumi, A. E. Hamilton, L. Aghajanova, K. C. Vo, L. C. Giudice. Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, CA; Gynecology and Obstetrics, Kyoto University Graduate School of Medicine, Kyoto, Sakyo-ku, Japan.
Vol. 88, Suppl 1, September 2007
between luteal serum progesterone levels and the occurrence of pregnancy following ovulation induction (OI). DESIGN: Retrospective analysis of 1554 cycles from patients with oligoanovulatory infertility and/or amenorrhea (WHO II classification). MATERIALS AND METHODS: Inclusion criteria for the analysis were: one or two progesterone levels in the mid-luteal phase, one between days 5 to 7 and the second between days 8 to 10 post hCG (the higher of the two levels was used for statistical analysis) and complete data on the outcome of the cycle. The primary endpoint for all studies was ovulation. All patients included were treated with FSH using a step up protocol. RESULTS: Baseline demographic characteristics for the population were: mean age of 30.1 3.7 (range 19–39) and mean BMI of 24.8 4.8 (range 16–37). Overall, out of 1554 cycles, 346 achieved a pregnancy (22.3%); 295 of them were clinical pregnancies (19.0%) and 51 had a biochemical pregnancy (3.3%). Live birth rate was 16.6% (258/1154). 87.5% of the clinical pregnancies led to live births. The relationship between clinical and biochemical pregnancy rates and live birth rates vs. progesterone levels is shown on Figure 1. Clinical pregnancy rates in cycles with progesterone levels above 10 ng/mL was 22.1%; 12.0% with progesterone levels between 5 and 10 ng/ml and 3.4% with levels less than 5 ng/mL. There was no relationship between progesterone levels and the occurrence of biochemical pregnancies.
P-262 THE ROLE OF BONE MORPHOGENETIC PROTEIN-7 (BMP-7) IN THE HUMAN ENDOMETRIUM. O. Yoshino, Y. Osuga, T. Yano, Y. Taketani. Obstetrics and Gynecology, Tokyo University, Bunkyo-ku, Tokyo, Japan. OBJECTIVE: Bone morphogenetic proteins (BMPs) play critical roles in cellular differentiation in multiple tissues. Among BMPs, it is reported that BMP-7 is expressed in the endometrium. In the endometrium, the differentiation process is occurred at secretory phase as decidualization of endometrial cells for successful implantation and pregnancy. We analyzed the role of BMP-7 in the human endometrium, focusing on decidualization. DESIGN: Experimental study using human endometrial cells. MATERIALS AND METHODS: Informed consent for tissue sampling was obtained from each patient. Endometrial tissues were obtained from the patients who underwent operation for benign diseases. The mRNA expression of BMP-7 in the endometrium was analyzed by quantitative reverse transcription-polymerase chain reaction (RT-PCR, n ¼ 24). Endometrial epithelial and stromal cells were cultured separately followed by checking BMP-7 mRNA. In vitro decidualization of stromal cells were induced with estradiol (E: 10 ng/ml) and progesterone (P: 100 ng/ml) for up to 12 days culture. Recombinant BMP-7 (10–100 ng/ml) was added to this culture system, followed by measuring prolactin concentration in the supernatant. RESULTS: The quantitative RT-PCR analyses showed that BMP-7 mRNA was diminished significantly in the late secretory phase compared to other phases. The BMP-7 mRNA was detected in epithelial and stromal cells. With 6 days of EP treatment, cultured stromal cells started secretion of a differentiation marker, prolactin. But in the presence of BMP-7, prolactin concentration decreased to undetectable level. After 12 days incubation with EP and BMP-7, prolactin concentration was decreased at BMP-7 dose-dependent manner and decreased by 60% with 100 ng/ml BMP-7. CONCLUSIONS: In vitro study showed that BMP-7 has a potential to inhibit endometrial cells differentiation. The attenuation of BMP-7 mRNA expression in the late secretory phase might be one of the mechanisms to induce endometrial cells differentiation. Supported by: Japan Society for the Promotion of Science. P-263 CORRELATION BETWEEN LUTEAL SERUM PROGESTERONE LEVELS AND PREGNANCY IN OVULATION INDUCTION. D. R. Tredway, D. W. Warne, A. Eshkol, V. Alam. EMD Serono, Inc., Rockland, MA; MERCK Serono, Geneva, Switzerland. OBJECTIVE: Progesterone levels are commonly used for assessment of ovulation during clinical trials. This analysis evaluates the correlation
FERTILITY & STERILITYÒ
Figure
CONCLUSIONS: The probability of achieving a clinical pregnancy is correlated with progesterone levels above 5 ng/mL. With a luteal progesterone level above 20 ng/mL, a 28% clinical pregnancy rate was achieved of which 88% resulted in live births. Supported by: All clinical studies were conducted by Serono. P-264 SUBENDOMETRIAL VASCULARIZATION AND IN VITRO FERTILIZATION OUTCOMES. M. Scioscia, F. Lorusso, M. Palmisano, G. Serratı`, G. Lamanna, R. Depalo. Department of Gynecology, Obstetrics and Neonatology, University of Medical Science of Bari, Bari, Italy. OBJECTIVE: To evaluate changes in subendometrial vascularization during IVF cycles and to prospectively analyze whether ultrasonographic measurements of power Doppler areas predict IVF outcomes. DESIGN: Prospective analysis in a tertiary center for assisted reproduction. MATERIALS AND METHODS: Serial transvaginal scans were performed in a single cycle of 48 women undergoing IVF treatment. Subendometrial vascularization was determined by power Doppler ultrasonography on the day of hCG administration, and immediately before pick up and embryo transfer. Ultrasound evaluations were performed by a single operator using fixed power Doppler settings. A longitudinal view of the uterus was obtained and the Doppler box placed over the thickest part of the endometrium. All vascular areas were measured on a single frozen section and recorded as areas (mm2) and in a semiquantitative scale (<3, 3–6, 6.1–9, >9 mm). Ultrasonographic parameters and conception rates were considered for the analysis. RESULTS: Clinical pregnancy rate/cycle and the implantation rate were 25% and 11.8%, respectively. Endometrial thickness was similar among groups. Subendometrial vascularization areas were significantly larger in
S195
patients who achieved an ongoing pregnancy than in those women with nonconceptional cycles (190.6 35.2 mm2 vs. 323.7 43.5 mm2; P<0.001). Maternal age was inversely correlated with subendometrial vascularization at embryo transfer (r2 ¼ 0.29; P<0.1). CONCLUSIONS: Increasing patient age is associated with lower subendometrial vascularization and implantation rate, regardless endometrial thickness. These findings may help at understanding the decreasing endometrial receptivity as woman age progresses. Furthermore, sonographic evidence of poor vascularization may allow early prediction of a nonreceptive endometrium providing information about whether to perform the embryo transfer or to cryopreserve the embryos until endometrium is receptive during a next cycle. Supported by: None. P-265 INDIAN HEDGEHOG AND ITS ASSOCIATED DOWN-STREAM TARGETS ARE ALTERED IN RESPONSE TO IN VIVO CDB-2914 ADMINISTRATION. E. D. Levens, Q. Wei, L. K. Nieman. Reproductive Biology and Medicine Branch, National Institute of Child Health and Human Development, NIH, Bethesda, MD; Combined Federal Fellowship in Reproductive Endocrinology and Infertility at the National Institutes of Health, Walter Reed Army Medical Center, National Naval Medical Center, and Uniformed Services University of the Health Sciences, Bethesda, MD.
tive Endocrinology and Infertility, University of North Carolina, Chapel Hill, NC; Molecular and Integrative Physiology, University of Illinois at UrbanaChampaign, Urbana, IL. OBJECTIVE: The transcription factor CCAAT/enhancer-binding protein b (C/EBPb) is a critical mediator of murine endometrial epithelial and stromal cell proliferation and differentiation. Consequently, female mice lacking the C/EBPb gene are infertile. Previous studies have demonstrated the presence of C/EBPb mRNA in human endometrium and upregulation of C/EBPb during in vitro stromal decidualization. In order to further define the role of C/EBPb in human endometrium, we characterized temporal changes in C/ EBPb mRNA abundance over the normal human menstrual cycle. DESIGN: Laboratory analysis. MATERIALS AND METHODS: Volunteers (ages 18–35) were randomized to undergo endometrial sampling on a specific cycle day, and luteal phase samples were timed using the patient’s urinary luteinizing hormone (LH) surge. Real-time RT-PCR was performed on total RNA, in triplicate, using probe-primer sets specific for C/EBPb and the constitutively-expressed gene, PPIA. The data were grouped by cycle phase and analyzed by one way analysis of variance. Endometrial histology confirmed LH dating. RESULTS: Of the 50 samples obtained, 23, 6, 15, and 6 samples were in the proliferative, early secretory, midsecretory, and late secretory phases, respectively. C/EBPb mRNA expression was highest in the early and late secretory phases and lowest in the midsecretory phase. The relative difference between midsecretory and late secretory expression was 4-fold.
OBJECTIVE: Acting via its receptor (PR), progesterone (P4) rapidly induces Indian hedgehog (IHH) in the mouse and thus stimulates endometrial cell proliferation and differentiation via downstream targets (Smo, Ptc-1, Gli1, and Gli2). CDB-2914 (CDB), a selective P4 modulator, binds and occupies both PRA and PRB at higher affinity than P4. Having confirmed differential expression of Ihh in CDB treated human endometrium, our objective was to determine whether Ihh signaling was also affected. DESIGN: Human genome array, real-time RT PCR (RT-PCR) and immunohistochemistry (IHC). MATERIALS AND METHODS: After IRB approval, pre-menopausal patients received CDB (10 or 20 mg; n ¼ 8) or placebo (n ¼ 6) for 90 days before hysterectomy for symptomatic leiomyomata. No other hormonal therapy was given. Endometrium was obtained at surgery from proliferative (n ¼ 10) and secretory (n ¼ 3) phases as determined by histology. Total RNA was isolated and subjected to RT-PCR. IHC was performed using a goat anti-human Ihh polyclonal antibody (sc-1196). Staining intensity was evaluated using semi-quantitative H-scores. Proliferative phase endometrium was analyzed using Wilcoxon rank sum test; P<0.05 was considered significant. RESULTS: RT-PCR validated Ihh expression and the expression of genes involved in its signaling: Smo, Ptc, Gli1 and Gli2. CDB treatment significantly up-regulated Ihh and Gli1 but did not affect Smo, Ptc and Gli2 (figure). IHC revealed increased Ihh staining intensity in both endometrial glands and stroma in response to CDB (P¼0.015).
Figure
Figure
CONCLUSIONS: Ihh may be an important pathway by which progesterone signals in human endometrium. These results for the first time demonstrate altered Ihh signaling pathways due to long-term treatment with CDB-2914. Since these gene products have been implicated in cellular growth and differentiation, this pathway may be an integral regulatory mechanism of human endometrial function. Supported by: This research was supported by the intramural program of NICHD, NIH, Bethesda, MD, and by HRA Pharma, Paris, France. P-266 CYCLIC REGULATION OF TRANSCRIPTION FACTOR C/EBP IN HUMAN ENDOMETRIUM. B. J. Plante, M. K. Bagchi, L. Yuan, M. A. Fritz, S. L. Young. Obstetrics and Gynecology/Division of Reproduc-
S196
Abstracts
CONCLUSIONS: C/EBPb mRNA expression by whole endometrium peaks in the early and late secretory phases. The increase in the late secretory phase is predominantly due to marked increases at 13 and 14 days after the LH surge, suggesting that C/EBPb may play a role in preparing for menstruation. The finding of a nadir in C/EBPb expression during the midsecretory phase is surprising since ‘‘predecidualization’’ begins during this phase and C/EBPb plays a key role in murine endometrial decidualization. At present, the changes of expression in each cell type remain unclear, but ongoing experiments using in situ hybridization and immunohistochemistry will clarify changes in C/EBPb expression by specific cell types in human endometrium. Supported by: NICHD U54 HD035041–11 and the UNC Nova Carta Foundation. P-267 ESTROGEN-RESPONSIVE GENE EXPRESSION IN THE ENDOMETRIUM. L. Li, K. Tatsumi, A. E. Hamilton, L. Aghajanova, K. C. Vo, L. C. Giudice. Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, CA; Gynecology and Obstetrics, Kyoto University Graduate School of Medicine, Kyoto, Sakyo-ku, Japan.
Vol. 88, Suppl 1, September 2007