8 resultados para AROMATASE
em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo
Resumo:
Sexual differentiation in the brain takes place from late gestation to the early postnatal days. This is dependent on the conversion of circulating testosterone into estradiol by the enzyme aromatase. The glyphosate was shown to alter aromatase activity and decrease serum testosterone concentrations. Thus, the aim of this study was to investigate the effect of gestational maternal glyphosate exposure (50 mg/kg, NOAEL for reproductive toxicity) on the reproductive development of male offspring. Sixty-day-old male rat offspring were evaluated for sexual behavior and partner preference; serum testosterone concentrations, estradiol, FSH and LH; the mRNA and protein content of LH and FSH; sperm production and the morphology of the seminiferous epithelium; and the weight of the testes, epididymis and seminal vesicles. The growth, the weight and age at puberty of the animals were also recorded to evaluate the effect of the treatment. The most important findings were increases in sexual partner preference scores and the latency time to the first mount; testosterone and estradiol serum concentrations; the mRNA expression and protein content in the pituitary gland and the serum concentration of LH; sperm production and reserves; and the height of the germinal epithelium of seminiferous tubules. We also observed an early onset of puberty but no effect on the body growth in these animals. These results suggest that maternal exposure to glyphosate disturbed the masculinization process and promoted behavioral changes and histological and endocrine problems in reproductive parameters. These changes associated with the hypersecretion of androgens increased gonadal activity and sperm production.
Resumo:
In this study, we evaluated the effects of obesity and insulin resistance induced by a high-fat diet on prostate morphophysiology, focusing on cell proliferation, expression of androgen (AR) and estrogen receptors (ER) and proteins of the insulin signaling pathway. Adult male Wistar rats were fed a high-fat diet (20% fat) for 15 weeks, whereas control animals received a balanced diet (4% fat). Both groups were then divided and treated for 2 weeks with 1 mg/kg body weight/day of the aromatase inhibitor letrozole or vehicle only. The ventral prostate was analyzed with immunohistochemical, histopathological, stereological, and Western blotting methods. Obese rats showed insulin resistance, hyperinsulinemia, and reduced plasma testosterone levels. The incidence of prostatic intraepithelial neoplasia (PIN) was 2.7 times higher in obese rats and affected 0.4% of the gland compared with 0.1% PIN areas found in control rats. Obesity doubled cell proliferation in both prostate epithelium and stroma. AR content decreased in the prostate of obese rats and estrogen receptor beta (ER beta) increased in this group. Protein levels of insulin receptor substrate 1 and protein kinase B diminished in the obese group, whereas phosphatidylinositol 3-kinase (PI3K) increased significantly. Most structural changes observed in the prostate of obese rats normalized after letrozole treatment, except for increased stromal cell proliferation and ER beta expression, which might be associated with insulin resistance. This experimental model of obesity and insulin resistance induced by a high-fat diet increases cell proliferation in rat prostate. Such alterations are associated with decreased levels of AR and increased ER beta and PI3K proteins. This change can facilitate the establishment of proliferative lesions in rat prostate.
Resumo:
Our objectives were to investigate the possible role of VEGFA in bovine placenta steroid synthesis and to determine whether cloned derived placental cells present similar responses as non-cloned ones. Placental cells from cloned (term) and non-cloned (days 90, 150, 210 and term) pregnancies were isolated and treated with VEGFA (50 ng/ml) for 24, 48 or 96 h. Progesterone (P-4) and estrone sulfate (E1S) were assessed by RIA, while aromatase P450-positive cells were quantified using the point counting test. The percentages of steroidogenic and non-steroidogenic populations were determined by flow cytometry. VEGFA augmented or decreased P-4 and E1S concentrations as well as aromatase P450-positive cell density, depending on gestational age and time in culture. The percentage of steroidogenic cells was lower than that of non-steroidogenic ones for each culture time (P < 0.05). VEGFA treatment did not change the proportion of steroidogenic and non-steroidogenic cells. Placental cells derived from cloned pregnancies presented higher concentrations of E1S and P4 than the non-cloned group. However, aromatase P450-positive cells were similar between groups (P > 0.05). VEGFA treatment altered P-4 and E1S levels in placental cells depending on type of gestation. These results suggest that VEGFA acts locally in the bovine placenta to modulate steroidogenesis during gestation, but in a different pattern between cloned and non-cloned derived placental cells at term. Therefore, this factor can be considered an important regulator of placental development and function. (C) 2012 Elsevier Ltd. All rights reserved.
Resumo:
To investigate the effects of repeated crack-cocaine inhalation on spermatogenesis of pubertal and mature Balb/c mice, ten young (Y-ex) and ten adult (A(ex)) Balb/c mice were exposed to the smoke from 5 g of crack with 57.7% of pure cocaine in an inhalation chamber, 5 days/week for 2 months. The young (Y-c) and adult (A(c)) control animals (n = 10) were kept in a specially built and controlled animal house facility. The morphologic analysis of both testes of all animals included the analysis of quantitative and qualitative histologic parameters to assess the effect of crack-cocaine on spermatogenesis and Leydig cells. Apoptosis was determined by immunolabeling with caspase-3 antibodies. Compared to the Y-c animals, Y-ex animals showed a significant reduction in the number of stage VII tubules per testis (p = 0.02), Sertoli cells (p < 0.001) and elongated spermatids (p = 0.001). Comparisons between the Y-ex and A(ex) groups identified a significant reduction in the number of Sertoli cells (p < 0.001) and round spermatids (p < 0.001) in the Y-ex group and a significant increase in apoptotic Leydig cells (p = 0.04) in the A(ex) group. The experimental results indicate that crack-cocaine smoke inhalation induced spermatogenesis disruption in chronically exposed mice, particularly in pubertal mice.
Resumo:
Aims: This study aimed to describe the expression of oestrogen receptor (ER)alpha, ER beta and aromatase in salivary gland adenoid cystic carcinoma (ACC). Methods and results: ER alpha, ER beta and aromatase expression was analysed by immunohistochemistry in tissue microarray blocks from 38 cases of ACC and seven normal salivary glands. The intracellular localization and amount of total protein expression were investigated by immunofluorescence and western blotting in an ACC cell line. Western blotting analysis showed overexpression of ER alpha, ER beta and aromatase in the ACC cell line; however, with immunofluorescence, only ER beta was shown to be expressed in the nucleus. Immunohistochemistry revealed positive nuclear expression of ER beta, positive cytoplasmic expression of aromatase and a lack of ER alpha expression as compared with normal salivary glands. Conclusions: The nuclear expression of ER beta indicates that oestrogen may be active in ACC and possibly able to mediate E2-targeted gene transcription. This study strongly suggests that ER beta may be involved in tumour progression, playing a role in tumour development, and thus corroborating the indication for ER antagonists in the clinical control of ACC. This study opens a new perspective on the potential use of anti-oestrogens and aromatase inhibitors as therapeutic agents against ACC.
Resumo:
Chrysin is one of the natural flavonoids present in plants, and large amounts are present in honey and propolis. In addition to anticancer, antioxidation, and anti-inflammatory activities, chrysin has also been reported to be an inhibitor of aromatase, an enzyme converting testosterone into estrogen. The present study evaluated the mutagenicity of this flavonoid using micronucleus (MN) with HepG2 cells and Salmonella. Cell survival after exposure to different concentrations of chrysin was also determined using sulforhodamine B (SRB) colorimetric assay in HepG2 cells and the influence of this flavonoid on growth of cells in relation to the cell cycle and apoptosis. TheMN test showed that from 1 to 15 mu M of this flavonoid mutagenic activity was noted in HepG2 cells. The Salmonella assay demonstrated a positive response to the TA100 Salmonella strain in the presence or absence of S9, suggesting that this compound acted on DNA, inducing base pair substitution before or after metabolism via cytochrome P-450. The SRB assay illustrated that chrysin promoted growth inhibition of HepG2 cells in both periods studied (24 and 48 h). After 24 h of exposure it was noted that the most significant results were obtained with a concentration of 50 mu M, resulting in 83% inhibition and SubG0 percentage of 12%. After 48 h of incubation cell proliferation inhibition rates (97% at 50 mu M) were significantly higher. Our results showed that chrysin is a mutagenic and cytotoxic compound in cultured human HepG2 cells and Salmonella typhimurium. Although it is widely accepted that flavonoids are substances beneficial to health, one must evaluate the risk versus benefit relationship and concentrations of these substances to which an individual may be exposed.
Resumo:
The birth of a child with ambiguous genitalia is a challenging and distressing event for the family and physician and one with life-long consequences. Most disorders of sexual differentiation (DSD) associated with ambiguous genitalia are the result either of inappropriate virilization of girls or incomplete virilization of boys. It is important to establish a diagnosis as soon as possible, for psychological, social, and medical reasons, particularly for recognizing accompanying life-threatening disorders such as the salt-losing form of congenital adrenal hyperplasia. In most instances, there is sufficient follow-up data so that making the diagnosis also establishes the appropriate gender assignment (infants with congenital adrenal hyperplasia, those with androgen resistance syndromes), but some causes of DSD such as steroid 5 alpha-reductase 2 deficiency and 17 beta-hydroxysteroid dehydrogenase deficiency are associated with frequent change in social sex later in life. In these instances, guidelines for sex assignment are less well established.
Resumo:
OBJECTIVE: The values of bone mineral density (BMD) were compared in postmenopausal women with and without breast cancer. METHODS: A cross-sectional study was conducted, including 51 breast cancer survivors (BCS) and 71 women without breast cancer, who were non-users of hormone therapy, tamoxifen, or aromatase inhibitors. BMD T-scores and measurements in grams per centimeter squared (g/cm²) were obtained at the femoral neck, trochanter, Ward's triangle, and lumbar spine. Osteopenia and osteoporosis were grouped and categorized as abnormal BMD. Unconditional logistic regression analysis was used to estimate the odds ratios (OR) of abnormal BMD values as measures of association, with 95% confidence intervals (CIs), adjusting for age, years since menopause, parity, and body mass index (BMI). RESULTS: The mean age of the women with and without breast cancer was 54.7 ± 5.8 years and 58.2 ± 4.8 years (p < 0.01), respectively. After adjusting for age, parity and BMI, abnormal BMD at the femoral neck (adjusted OR: 4.8; 95% CI: 1.5-15.4), trochanter (adjusted OR: 4.6; 95% CI: 1.4-15.5), and Ward's triangle (adjusted OR: 4.5; 95% CI: 1.5-12.9) were significantly more frequent in postmenopausal BCS than in women without breast cancer. Postmenopausal BCS had a significantly lower mean BMD at the trochanter (0.719 vs. 0.809 g/cm², p < 0.01) and at the Ward's triangle (0.751 vs. 0.805 g/cm², p = 0.03). CONCLUSION: The prevalence of abnormal BMD was higher in postmenopausal BCS than in postmenopausal women without breast cancer. Bone health requires special vigilance and the adoption of interventions should be instituted early to minimize bone loss in BCS.