Differential effects of androgens and estrogens over cellular GH sensitivity in HEPG2 cells.

Testosterone and estrogen concentrations progressively increase during puberty, and in association with growth hormone (GH), lead to the increase in height velocity known as the pubertal growth spurt. Very limited information is available however, regarding the possible effects of sex steroids over GH cellular sensitivity. OBJECTIVE: To investigate the effects of different concentrations of testosterone, estradiol and dihydrotestosterone over the GH intracellular signaling pathway. METHODS: We evaluated the effects of these sex steroids on the nuclear phosphorylation of STAT5b and IGF-1 expression, in HEPG2 human hepatoma cells. In addition, we studied whether Tamoxifen (TAM), can modulate these effects. RESULTS: The highest concentration of T tested (10 ng/mL) co-incubated with a fixed concentration of GH (40 ng/mL) increased nuclear STAT5b phosphorylation compared with GH alone (1.34 ± 0.2 vs 0.6 ± 0.09 AU; *p < 0.05), as well as IGF-1 expression (0.6 ± 0.03 vs 0.32 ± 0.05 AU; *p < 0.05). This effect was not observed with lower concentrations of T tested (1 and 5 ng/mL). A similar increase in nuclear STAT5b phosphorylation was observed with the lowest concentration of E2 tested (20 pg/mL), co-incubated with the same fixed concentration of GH (3.6 ± 0.5 vs 1.28 ± 0.33 AU; *p < 0.05). This effect was also associated with an increase in IGF-1 expression (0.73 ± 0.02 vs 0.39 ± 0.04 AU; *p < 0.05). These results were not observed with higher concentrations of E2 tested (75 and 200 pg/mL). DHT at concentrations of 0.1, 0.25 and 0.5 ng/mL, co-stimulated with GH, did not change cytoplasmic STAT5b phosphorylation, nuclear STAT5b or IGF-1 expression. In addition, the co-incubation of TAM with the highest concentration of T tested (10 ng/mL) and GH (40 ng/mL) did not change cytoplasmic, nuclear pSTAT5 levels or IGF-1 expression. CONCLUSIONS: T and E2 potentiate the GH signaling pathway in a concentration-dependent fashion. The observation that the non-aromatizable androgen dihydrotestosterone does not stimulate this pathway, and that the effects of T are blocked with TAM, suggests that the effects of T over the GH signaling pathway appear to be mediated by estrogen.

CO2 Hydrogenation Catalyzed by a Ruthenium Protic N-Heterocyclic Carbene Complex.

We describe the hydrogenation of CO2 to formate catalyzed by a Ru(II) bis(protic N-heterocyclic carbene, p-NHC) phosphine complex [Ru(bpy)(MeCN)(PPh(p-NHC)2)](PF6)2 (1). Under catalytic conditions (20 µmol catalyst, 20 bar CO2, 60 bar H2, 5 mL THF, 140 °C, 16 h), the activity of 1 is limited only by the amount of K3PO4 present in the reaction, yielding a nearly 1:1 ratio of turnover number (TON) to equivalents of K3PO4 (relative to 1), with the highest TON = 8040. Additionally, analysis of the reaction solution post-run reveals the catalyst intact with no free ligand observed. Stoichiometric studies, including examination of unique carbamate and hydride complexes as relevant intermediates, were carried out to probe the operative mechanism and understand the importance of metal-ligand cooperativity in this system.

Human endometrial stromal cells inhibit the pro-angiogenic stimulus of hCG in vitro.

During embryo implantation, endometrial angiogenesis is regulated by signals originating from the endometrium itself and the developing embryo. It has been suggested that hCG may play a pro-angiogenic role; therefore, we sought to understand its regulatory role in blood vessel formation in human endometrium using in vivo and in vitro models. In the in vivo model, we screened 16 angiogenesis-related transcripts in the endometrium upon intrauterine administration of hCG. Oocyte donors were recruited and during their controlled ovarian stimulation cycle received a single dose of hCG or vehicle on the day of oocyte pick up during a cycle of ovarian stimulation. One hour before obtaining an endometrial sample, women received an intrauterine administration of vehicle or hCG (500, 1500 and 5000 IU). Transcript and protein analysis showed that MMP3 and VEGFA increased, whereas TIMP1 decreased. The in vitro analysis studied the angiogenic potential of conditioned medium (CM) from primary cultures of human endometrial stromal cells (ESC) stimulated with hCG. Using a 2D and 3D in vitro angiogenesis assays, our results indicate that CM from ESC almost completely inhibits the capillary-like structure formation in endothelial cells, overriding the pro-angiogenic effect of hCG; and this inhibition due to secreted factors present in CM specifically reduced the migration potential of endothelial cells. In conclusion, the endometrial stromal milieu seems to modulate the direct pro-angiogenic effects of hCG on endothelial cells during embryo implantation.

Differential expression of upstream stimulatory factor (USF) 2 variants in eutopic endometria from women with endometriosis: estradiol regulation.

BACKGROUND: Endometriosis, pro-inflammatory and invasive benign disease estrogen dependent, abnormally express in endometria the enzyme P450Arom, positively regulated by steroid factor-1 (SF-1). Our objective was to study the nuclear protein contents of upstream stimulating factor 2 (USF2a and USF2b), a positive regulator of SF-1, throughout the menstrual cycle in eutopic endometria from women with and without (control) endometriosis and the involvement of nuclear estrogen receptors (ER) and G-coupled protein estrogen receptor (GPER)-1. RESULTS: Upstream stimulating factor 2 protein contents were higher in mid (USF2b) and late (USF2a and USF2b) secretory phase in eutopic endometria from endometriosis than control (p < 0.05). In isolated control epithelial cells incubated with E2 and PGE2, to resemble the endometriosis condition, the data showed: (a) significant increase of USF2a and USF2b nuclear protein contents when treated with E2, PPT (specific agonist for ERα) or G1 (specific agonist for GPER1); (b) no increase in USF2 binding to SF-1 E-Box/DNA consensus sequence in E2-treated cells; (c) USF2 variants protein contents were not modified by PGE2; (d) SF-1 nuclear protein content was significantly higher than basal when treated with PGE2, E2 or G1, stimulation unaffected by ICI (nuclear ER antagonist); and (e) increased (p < 0.05) cytosolic protein contents of P450Arom when treated with PGE2, E2, PPT or G1 compared to basal, effect that was additive with E2 + PGE2 together. Nevertheless, in endometriosis cells, the high USF2, SF-1 and P450Arom protein contents in basal condition were unmodified. CONCLUSION: These data strongly suggest that USF2 variants and P450Arom are regulated by E2 through ERα and GPER1, whereas SF-1 through GPER1, visualized by the response of the cells obtained from control endometria, being unaffected the endogenously stimulated cells from endometriosis origin. The lack of E2 stimulation on USF2/SF-1 E-Box/DNA-sequence binding and the absence of PGE2 effect on USF2 variants opposite to the strong induction that they exert on SF1 and P450 proteins suggest different mechanisms and indirect regulations. The sustained USF2 variants protein expression during the secretory phase in eutopic endometria from women with endometriosis may participate in the pathophysiology of this disease strongly associated with infertility and its characteristic endometrial invasion to ectopic sites in the pelvic cavity.

IGF-IR signal transduction protein content and its activation by IGF-I in human placentas: relationship with gestational age and birth weight.

INTRODUCTION: The human placenta expresses the IGF-I and IGF-IR proteins and their intracellular signal components (IRS-1, AKT and mTOR). The aim of this study was to assess the IGF-IR content and activation of downstream signaling molecules in placentas from newborns who were classified by gestational age and birth weight. We studied placentas from 25 term appropriate (T-AGA), 26 term small (T-SGA), 22 preterm AGA (PT-AGA), and 20 preterm SGA (PT-SGA) newborns. The total and phosphorylated IGF-IR, IRS-1, AKT, and mTOR contents were determined by Western Blot and normalized by actin or with their respective total content. The effect of IGF-I was determined by stimulating placental explants with recombinant IGF-I 10-8 mol/L for 15, 30, and 60 minutes. RESULTS: The IGF-IR content was higher in T-SGA compared to T-AGA placentas, and the IRS-1 content was higher in PT-placentas compared with their respective T-placentas. The effect of IGF-I on the phosphorylated forms of IGF-IR was increased in T-SGA (150%) and PT-SGA (300%) compared with their respective AGA placentas. In addition, AKT serine phosphorylation was higher in PT-SGA compared to PT-AGA and T-SGA placentas (90% and 390% respectively). CONCLUSION: The higher protein content and response to IGF-I of IGF-IR, IRS-1, and AKT observed in SGA placentas may represent a compensatory mechanism in response to fetal growth restriction.

[Prevalence of endometriosis in 287 women undergoing surgical sterilization in Santiago Chile]. / Prevalencia de la endometriosis en mujeres sometidas a esterilización quirúrgica laparoscópica en un hospital de Santiago de Chile.

BACKGROUND: The clinical manifestations of endometriosis are infertility, dysmenorrhea, sexuality disturbances, and chronic pelvic pain. It is the cause of 30 to 50% of infertility cases. In developed countries, the prevalence of endometriosis among women undergoing surgical sterilization is approximately 6%. AIM: To determine the prevalence of endometriosis among women with proven fertility in Santiago de Chile. MATERIAL AND METHODS: Review of surgical protocols of 287 women aged 25 to 49 years, subjected to a surgical sterilization between 2007 and 2011. RESULTS: Endometriosis was found in 14 of the 287 women (4.9%). In spite of being asymptomatic, five of the 14 women with endometriosis were classified as severe, due to the presence of at least one endometrioma. In order of frequency, the most commonly affected anatomical sites were the ovary, the peritoneum, the posterior cul-de-sac and uterosacral ligaments. CONCLUSIONS: Our findings are very similar to those found elsewhere and suggest that fertile women could better tolerate endometriosis than their infertile counterparts.

Prevalencia de la endometriosis en mujeres sometidas a esterilización quirúrgica laparoscópica en un hospital de Santiago de Chile / Prevalence of endometriosis in 287 women undergoing surgical sterilization in Santiago Chile

Background: The clinical manifestations of endometriosis are infertility, dysmenorrhea, sexuality disturbances, and chronic pelvic pain. It is the cause of 30 to 50% of infertility cases. In developed countries, the prevalence of endometriosis among women undergoing surgical sterilization is approximately 6%. Aim: To determine the prevalence of endometriosis among women with proven fertility in Santiago de Chile. Material and Methods: Review of surgical protocols of 287 women aged 25 to 49 years, subjected to a surgical sterilization between 2007 and 2011. Results: Endometriosis was found in 14 of the 287 women (4.9%). In spite of being asymptomatic, five of the 14 women with endometriosis were classified as severe, due to the presence of at least one endometrioma. In order of frequency, the most commonly affected anatomical sites were the ovary, the peritoneum, the posterior cul-de-sac and uterosacral ligaments. Conclusions: Our findings are very similar to those found elsewhere and suggest that fertile women could better tolerate endometriosis than their infertile counterparts.

Acid-labile subunit (ALS) gene expression and protein content in human placentas: differences according to birth weight.

CONTEXT: In humans, IGF-I and -II have an important role in pre- and postnatal growth. The IGFs circulate in plasma principally as a ternary complex with the IGF binding protein-3 and an acid-labile subunit (ALS), which increases their half life. OBJECTIVES: The objectives of the study were to determine whether the human placenta expresses the mRNA and protein for ALS and to evaluate any possible differences in the mRNA and protein for ALS in placentas from small (SGA) and appropriate (AGA) or gestational age newborns. SUBJECTS/METHODS: We studied the placentas from 47 AGA and 42 SGA pregnancies. IGF-I, IGF-II, IGF binding protein-3, and ALS placental mRNA and protein contents were determined in both the basal and the chorionic plates of the placenta. RESULTS: We observed that the human placenta expresses the gene and protein for ALS. The ALS mRNA in SGA was higher compared with AGA placentas (0.15 ± 0.01 vs. 0.12 ± 0.01 arbitrary units, respectively, P < 0.05). In addition, the ALS protein content in SGA (31.7 ± 3.3 pmol/g) was higher compared with AGA (22.1 ± 2.3 pmol/g, P < 0.05) placentas. CONCLUSION: We describe that the human placenta expresses the mRNA and the protein for ALS, and we observed an increase in ALS mRNA expression and protein content in SGA compared with AGA placentas.

P450Arom induction in isolated control endometrial cells by peritoneal fluid from women with endometriosis.

OBJECTIVE: To study the effect of peritoneal fluid from women with (PF-E) and without (PF-C) endometriosis on P(450)Arom expression in endometrial cells. DESIGN: Experimental study. SETTING: University research unit. PATIENT(S): Forty women of reproductive age with (n = 22) or without (control; n = 18) endometriosis. INTERVENTION(S): Peritoneal fluid and eutopic endometrial samples were obtained during surgery from women with (n = 13 and 9, respectively) and without (n = 4 and 14, respectively) endometriosis. MAIN OUTCOME MEASURE(S): Expression study for P(450)Arom, steroid factor 1 (SF-1), chicken ovalbumin upstream transcription factor I (COUP-TFI), and COUP-TFII messenger RNA (reverse transcriptase-polymerase chain reacion) and/or protein (immunoblot) in isolated endometrial epithelial cells transfected or not with expression vector containing SF-1, COUP-TFI, or COUP-TFII complementary DNAs. RESULT(S): Basal messenger RNA and/or protein expression of P(450)Arom and SF-1 were augmented in endometriosis, and that of COUP-TF was diminished. In control cells, (Bu)(2)cAMP and PF-E increased P(450)Arom and SF-1 expression (but not COUP-TF expression) in a dose-dependent way, an effect not observed with PF-C, adsorbed PF-E, or 10(-5) M indomethacin. Transfected cells confirmed these results. Any treatments modified the studied molecules in endometriosis cells. CONCLUSION(S): These data indicate that molecules contained in PF-E favor an estrogenic microenvironment, suggesting a role in the etiopathogenesis of endometriosis enabling the survival, maintenance, and growth of endometrial implants in the ectopic locations.

Nuclear factor kappaB pathway and interleukin-6 are affected in eutopic endometrium of women with endometriosis.

In order to investigate the role of the nuclear factor kappaB (NFKB) pathway on gene expression in the eutopic endometrium in endometriosis, and in particular of interleukin-6 (IL6), we evaluated RELA, IkappaB kinase (CHUK), NFKBIA and IL6 expressions and NFKB DNA binding in eutopic endometrium from women with endometriosis. Eutopic endometrium was obtained from 37 women with endometriosis and 42 fertile women during laparoscopy. We analysed RELA, CHUK, NFKBIA and IL6 mRNA levels (RT-PCR); RELA, CHUK and NFKBIA proteins and p-NFKBIA/NFKBIA ratio (western blot); and NFKB binding (DNA shift assay) and IL6 concentration (ELISA) in endometrial explants. Our results indicate that mRNA and cytoplasmic proteins of RELA and CHUK exhibit constant levels in normal endometrium during the menstrual cycle. A dramatic increase (P<0.05) in NFKBIA mRNA expression, RELA nuclear presence and the mRNA and the protein of IL6 during late secretory phase was also observed in this tissue. By contrast, in eutopic endometrium from endometriosis patients, a decrease (P<0.05) in IL6 mRNA and protein (61%), NFKBIA mRNA (46%), p-NFKBIA/NFKBIA ratio (42%), RELA nuclear stromal (68%) and CHUK (48%) proteins were found exclusively during the late secretory phase compared with normal endometrium. In conclusion, the canonical activation of NFKB pathway is deregulated and may have reduced transcriptional function affecting NFKBIA and IL6 expression, genes related local proinflammatory processes. These molecular alterations observed during the late secretory phase in eutopic endometrium from endometriosis patients constitute a NFKB system dysfunction, suggesting that NFKB could be an important factor in endometriosis aetiology.

Expression and activity of 11beta-hydroxysteroid dehydrogenase type 1 enzyme in subcutaneous and visceral adipose tissue of prepubertal children.

BACKGROUND: Glucocorticoid excess promotes visceral obesity and cardiovascular disease. Ligand availability to the glucocorticoid receptor is controlled by isoforms of 11beta-hydroxysteroid dehydrogenase (11beta-HSD) which converts endogenous cortisone to active cortisol. AIM: To evaluate the expression and activity of 11beta-HSD1 in subcutaneous adipose tissue (SC) and visceral adipose tissue (VAT) in prepubertal children with normal weight. METHODS: Fourteen patients (11 female/3 male) with a mean age of 6.9+/-0.9 years and a body mass index (BMI) of 17.4+/-0.61 underwent elective open abdominal surgery. RESULTS: Expression of 11beta-HSD1 mRNA in SC and VAT was similar (0.8+/-0.15 vs. 0.61+/-0.12 AU). The activity of this enzyme in SC was significantly lower compared to VAT (1.42+/-0.39 vs. 2.79+/-0.61 ng cortisol/g tissue/24 h, p<0.05). In addition, we observed a significant direct correlation with the expression of 11beta-HSD1 in VAT adipose tissue with the patient's BMI (r=0.825, p=0.002). CONCLUSIONS: This correlation together with the increased activity of this enzyme in visceral adipose tissue might contribute to decreased hepatic insulin sensitivity due to increased portal cortisol when BMI increases. These observations appear to be particularly important in children born with low birth weight who develop rapid early weight gain.

Sex hormone-binding globulin expression in the endometria of women with polycystic ovary syndrome.

OBJECTIVE: To evaluate the protein and messenger RNA expression of sex hormone-binding globulin (SHBG) in endometria from women with polycystic ovary syndrome (PCOS). DESIGN: Case-control study. SETTING: Hospital research unit. PATIENT(S): Thirty-three women with PCOS, and 17 fertile, healthy women of similar age to those with PCOS. INTERVENTION(S): Endometrial and blood samples were obtained from women with PCOS (PCOSEs) and from control women (CEs) during the proliferative phase of the menstrual cycle. MAIN OUTCOME MEASURE(S): Expression studies for SHBG (immunohistochemistry and reverse transcription-polymerase chain reaction). Hormonal studies for determining sex steroids (T, P, and E(2)) and SHBG concentration. Insulin sensitivity was assessed by composite insulin sensitivity index (ISI(composite)). RESULT(S): In stroma, the protein expression of SHBG was lower in PCOSEs than in CEs. Epithelial cells had a similar expression of SHBG protein in both groups. Messenger RNA of variant 548 base pairs (wild-type) tended to be lower in PCOSEs compared to CEs. When PCOSEs were classified by insulin resistance, the PCOSEs with normal insulin sensitivity showed an expression of stromal SHBG similar to that observed in CEs. CONCLUSION(S): The low SHBG expression in the stromal compartment of endometria from women with PCOS with insulin resistance may contribute to generate an abnormal steroid milieu in the endometria of these women.

Augmented cell survival in eutopic endometrium from women with endometriosis: expression of c-myc, TGF-beta1 and bax genes.

BACKGROUND: Endometriosis is a common gynaecological disorder characterized by the presence of endometrial tissue outside of the uterus. The fragments in normal menstruation are composed of necrotic and living cells, which do not survive in ectopic locations because of programmed cell death. The aim of this study was to evaluate if the balance between cell proliferation and apoptosis is changed in eutopic endometrium from women with endometriosis throughout the menstrual cycle by studying bax (pro-apoptotic), c-myc (regulator of cell cycle) and TGF-beta1 (involved in cell differentiation) genes. METHODS: Eutopic endometrium was obtained from: 30 women with endometriosis (32.8 +/- 5 years) and 34 fertile eumenorrheic women (36 +/- 5.3 years). We analyzed apoptosis (TUNEL: DNA fragmentation); cell proliferation (immunohistochemistry (IHC) for Ki67); c-myc, bax and TGF-beta1 mRNA abundance (RT-PCR) and TGF-beta1 protein (IHC) in endometrial explants. RESULTS: Cell proliferation strongly decreased from proliferative to late secretory phases in glands, but not in stroma, in both endometria. Positive staining in glands and stroma from proliferative endometrium with endometriosis was 1.9- and 2.2-fold higher than control endometrium, respectively (p < 0.05). Abundance of c-myc mRNA was 65% higher in proliferative endometrium from endometriosis than normal tissue (p < 0.05). TGF-beta1 (mRNA and protein) augmented during mid secretory phase in normal endometrium, effect not observed in endometrium with endometriosis. In normal endometrium, the percentage of apoptotic epithelial and stromal cells increased more than 30-fold during late secretory phase. In contrast, in endometrium from endometriosis, not only this increase was not observed, besides bax mRNA decreased 63% versus normal endometrium (p < 0.05). At once, in early secretory phase, apoptotic stromal cells increased 10-fold with a concomitant augment of bax mRNA abundance (42%) in endometria from endometriosis (p < 0.05). CONCLUSION: An altered expression of c-myc, TGF-beta1 and bax was observed in eutopic endometrium from endometriosis, suggesting its participation in the regulation of cell survival in this disease. The augmented cell viability in eutopic endometrium from these patients as a consequence of a reduction in cell death by apoptosis, and also an increase in cell proliferation indicates that this condition may facilitate the invasive feature of the endometrium.

Molecular study of the 3 beta-hydroxysteroid dehydrogenase gene type II in patients with hypospadias.

To determine whether some patients with idiopathic hypospadias have HSD3B2 mutations, we genotyped this locus in 90 patients with hypospadias (age, 6.0 +/- 0.4 yr) and 101 healthy fertile male controls. We measured basal plasma renin activity and performed an ACTH test for determination of 17-OH-pregnenolone, 17-OH-progesterone, cortisol, dehydroepiandrosterone sulfate, and androstenedione and an human chorionic gonadotropin test for determination of androstenedione, testosterone, and dihydrotestosterone. We did not observe a clear steroidogenic pattern suggestive of 3 beta-HSD deficiency in any patient. DNA was extracted from peripheral lymphocytes; and exons 1, 2, 3, and 4 were amplified by PCR and analyzed by denaturing gradient gel electrophoresis. An abnormal electrophoretic migration pattern of exon 4 was observed in five patients. Two patients had missense heterozygous mutations (S213T and S284R). In another three patients, we observed heterozygous nucleotide variants in exon 4 that did not produce a change in amino acids (A238, T259, T320). In vitro enzymatic activity was diminished by 40% and 32% in the S213T and S284R heterozygous mutations, respectively. One control exhibited a heterozygous mutation in exon 3 (V78I), which did not alter in vitro enzyme activity. In addition, we observed possible polymorphisms in intron 1 in four patients and one control. We conclude that subtle molecular abnormalities in the HSD3B2 gene may be observed in some patients with apparent idiopathic hypospadias but that this finding is uncommon.

Differential in vitro actions of nitric oxide on human endometrial cell survival.

OBJECTIVE: To investigate the presence of caspase-3 and Bcl-2 concentration in human endometrial tissue throughout the menstrual cycle, and study the effect of nitric oxide (NO) on cell proliferation and apoptosis during culture. DESIGN: Expression of caspase-3 and Bcl-2 concentration in endometrial explants, and examination of L-arginine (L-Arg) effect on epithelial and stromal cell proliferation and apoptosis in vitro. SETTING: Prospective study.Twenty-seven eumenorrheic women (37 +/- 1.2 years). INTERVENTION(S): Endometrial samples were obtained with Pipelle suction curette from the corpus of the uterus. MAIN OUTCOME MEASURE(S): Apoptosis (annexin V-FITC binding), Bcl-2 concentration (ELISA), caspase-3 (immunohistochemistry), cell proliferation (spectrophotometric assay), and gene expression (RT-PCR). RESULT(S): Caspase-3 was detected by immunoassay in epithelial tissue throughout the menstrual cycle and in stroma during secretory phase. The Bcl-2 concentration was similar in endometrial homogenates obtained throughout the menstrual cycle, but L-Arg decreased Bcl-2 only in endometrium from the proliferative phase. In epithelial cells, NO increased apoptosis by 2.1 +/- 0.2-fold, augmented mRNA expression of Bax, and reduced expression of Bcl-2 compared with basal cultures. In stromal cells, NO increased cell proliferation in a dose-dependent manner, an effect that was blocked by a NO synthase inhibitor. CONCLUSION(S): These data indicate that NO has a differential regulatory function on endometrial cell survival, as indicated by the results on stromal cell proliferation and epithelial cell apoptosis during culture, which suggests paracrine interactions between both cell types.

[P450Arom and estrogenic microenvironment of eutopic endometria in endometriosis]. / P450Arom y microambiente estrogénico en endometrios eutópicos de mujeres con endometriosis.

BACKGROUND: Endometriosis, a common gynecologic disorder characterized by endometrial glands and stroma outside the uterus, is diagnosed by direct visualization of peritoneal and ovarian implants during laparoscopy. AIM: To study the estrogenic microenvironment in eutopic endometria of women with and without endometriosis. PATIENTS AND METHODS: Eutopic endometria, obtained during laparoscopy from 23 women with endometriosis and 20 fertile cyclic women undergoing tubal sterilization, was studied. P450Arom mRNA expression (RT-PCR) was measured. Also, P450Arom activity was assessed measuring testosterone conversion to estradiol and the concentration of this last hormone in cultured endometrial explants. RESULTS: Age and body mass index was similar in both groups studied. Seventy nine percent of endometria from women with endometriosis and in 29.4% from control group expressed P450Arom mRNA (p <0.01). The intensity of the band was higher in secretory endometria from women with endometriosis when compared to controls (p <0.01), but it was similar during the proliferative phase. Estradiol secretion to the culture media by proliferative endometria explants from women with endometriosis was 3-fold higher than secretory endometria (p <0.01) and endometria from control women in both phases. P450Arom activity, in the presence of testosterone, was 7-fold higher in endometrial cultures from women with endometriosis, when compare with the basal culture (p <0.01). However, in endometrial explant cultures from control women, this activity was not statistical different. CONCLUSIONS: These results indicate that in women with endometriosis, the microenvironment in the endometria is estrogenic as a consequence of an increased expression and activity of the P450Arom.