In cattle fattening, the illicit use of growth promoters (GPs) represents a major problem. The synthetic corticosteroid dexamethasone (DEX) is the GP mostly used, alone or in combination with other steroids or beta-agonists. Recently, GPs were shown to disrupt some cattle cytochromes P450 (CYPs) at the post-transcriptional level; therefore, the effects of two illicit protocols containing DEX (alone or together with 17beta-estradiol, 17betaE) upon main cattle liver drug metabolizing enzymes (DMEs) mRNAs and related transcription factors were investigated by quantitative real time RT-PCR. Eleven genes, out of the 18 considered, were significantly modulated by GPs. Corticosteroid-responsive genes did not respond univocally, whereas retinoic X receptor alpha (RXRalpha) and estrogen receptor alpha (ERalpha) were upregulated depending on the illicit protocol used. Nowadays, an increasing interest has been noticed toward the detection of biomarkers of response (BMRs) to be used in the screening of GPs misuse in cattle farming. In the present study, CYP2B6-like, CYP2E1, glutathione S-transferase A1- and sulfotransferase A1-like (GSTA1- and SULT1A1-like) mRNAs were significantly modulated regardless of the GP, the illicit protocol, and the animal breed, representing promising BMRs. The usefulness of these BMRs needs to be characterized more in depth. less...

Abstract Estradiol valerate (EV)-induced polycystic ovaries (PCOs) in rats cause the anovulation and cystic ovarian morphology. We investigated whether treatment with HemoHIM influences the ovarian morphology and the expression of nerve growth factor (NGF) in an EV-induced PCO rat model. PCO was induced by a single intramuscular injection of EV (4 mg, dissolved in sesame oil) in adult cycling rats. HemoHIM was either administered orally (100 mg/kg of body weight/day) for 35 consecutive days or injected intraperitoneally (50 mg/kg of body weight) every other day after EV injection. Ovarian morphology was almost normalized, and NGF was normalized in the PCO + HemoHIM group. HemoHIM lowered the high numbers of antral follicles and increased the number of corpora lutea in PCOs. The results are consistent with a beneficial effect of HemoHIM in the prevention and treatment of PCO syndrome. less...

PURPOSE: The neurotherapeutic effects of nerve electrical stimulation and gonadal steroids have independently been demonstrated. The purpose of this study was to investigate the therapeutic potential of a combinatorial treatment strategy of electrical stimulation and gonadal steroids on peripheral nerve regeneration. METHODS: Following a facial nerve crush axotomy in gonadectomized adult male rats, testosterone propionate (TP), dihydrotestosterone (DHT), or estradiol (E(2)) was systemically administered with/without daily electrical stimulation of the proximal nerve stump. Facial nerve outgrowth was assessed at 4 and 7 days post-axotomy using radioactive labeling. RESULTS: Administration of electrical stimulation alone reduced the estimated delay in sprout formation but failed to accelerate the overall regeneration rate. Conversely, TP treatment alone accelerated the regeneration rate by approximately 10% but had no effect on the sprouting delay. Combining TP with electrical stimulation, however, maintained the enhanced rate and reduced the sprouting delay. DHT treatment alone failed to alter the regeneration rate but combining it with electrical stimulation increased the rate by 10%. E(2) treatment alone increased the regeneration rate by approximately 5% but with electrical stimulation, there was no additional effect. CONCLUSIONS: Electrical stimulation and gonadal steroids differentially enhanced regenerative properties. TP, an aromatizable androgen, augmented regeneration most, suggesting a synergism between androgenic and estrogenic effects. Therapeutically, combining electrical stimulation with gonadal steroids may boost regenerative properties more than the use of either treatment alone. less...

Endocrine therapies targeting estrogen action are pivotal for the prevention and treatment of ER-positive breast cancers. Previous studies sought to recreate hormone responsiveness by the stable expression of ERalpha in the ER-negative MDA-MB-231 breast cancer cells. Paradoxically, estrogen inhibits breast cancer cell growth when an exogenous ERalpha is expressed. In this study, we have built on previous studies by developing a Tet-off adenoviral system to express ERalpha in the ER-negative SKBr3 breast cancer cells that over-express both EGFR and HER2. This system efficiently delivers ERalpha and the expression level of ERalpha is controlled by doxycycline in a concentration-dependent manner. The growth of SKBr3 was inhibited by ERalpha expression and further inhibited in the presence of 1 nM 17beta-estradiol. SKBr3 cells were arrested at G0/G1 cell cycle upon ERalpha expression, which corresponded to an increase of p21Cip1/Waf1, hypo-phosphorylation of pRb and decrease of E2F1. Estrogen also reduced EGFR and HER2 expression in SKBr3 cells after ERalpha was expressed. Given that estrogen-induced increase of p21Cip1/Waf1 and decrease of E2F1 was also observed in MDA-MB-231 cells stably transfected with ERalpha, our results suggest that a common pathway might be shared by different breast cancer cell lines whose growth is suppressed by ectopic ERalpha and estrogen. less...

Phytoestrogens (PEs) are naturally occurring plant components produced in a large range of plants. They can induce biologic responses in vertebrates by mimicking or modulating the action or production of endogenous hormones. This study examined mixtures of 12 food relevant PEs for effects on steroid hormone production, aromatase activity, estrogenic activity, and for interaction with the androgen receptor. The results show that a mixture of all tested PEs increased estradiol production and decreased testosterone production in H295R human adrenal corticocarcinoma cells, indicating an induced aromatase activity. Furthermore, exposure of the H295R cells to isoflavonoids caused a decrease in testosterone production, and various mixtures of PEs significantly stimulated MCF-7 human breast adenocarcinoma cell growth and induced aromatase activity in JEG-3 choriocarcinoma cells. The estrogenic effect in the MCF7 cells of the isoflavonoid mixture and coumestrol was supported by an observed increase in progesterone receptor protein expression as well as a decreased ERalpha expression. Overall, the results support that nutrition-relevant concentrations of PEs both alone and in mixtures possess various endocrine disrupting effects, all of which need to be considered when assessing the effects on human health. less...

Females are more susceptible than males to several biliary tract diseases. Interleukin-6 (IL-6) is critical to triggering autoimmune reactions and contributes substantially to biliary epithelial cell (BEC) barrier function and wound repair, and estrogen differentially regulates IL-6 expression in various cell types. We hypothesized that estrogen might stimulate BEC IL-6 production. Exposure to physiologic levels of estradiol, in vitro, increased female mouse BEC (mBEC) IL-6 messenger RNA (mRNA) and protein expression, but either inhibited or had no effect on male mBECs. Female mBECs expressed higher concentrations of estrogen receptor-alpha (ERalpha) mRNA and protein and were also more dependent on estradiol for survival, in vitro. In vivo, elevated estrogen during estrous cycling in mice, and estrogen treatment of mice harboring an ERalpha(+) human cholangiocarcinoma resulted in increased BEC IL-6 mRNA and tumor viability, respectively. Both responses could be blocked by an ERalpha antagonist. Human cholangiocarcinoma cell lines differentially expressing ERalpha were treated with specific ERalpha and ERbeta agonists/antagonists to further test the relationship between estrogen stimulation, ERalpha expression, and IL-6 production. Results show that ERalpha, and not the underlying BEC sex, was responsible for estrogen-induced IL-6 production. Estrogen-induced proliferation of ERalpha-expressing cholangiocarcinoma was blocked by anti-IL-6 antibodies, indicating that at least some of the estrogen-trophic effects are mediated via IL-6. Finally, an association between ERalpha, IL-6, and phosphorylated signal transducer and activator of transcription 3 (pSTAT3) signaling was shown in female-predominant polycystic livers using immunohistochemical analyses, including multiplex quantum dot labeling. Conclusion: Estrogens stimulate IL-6 production in non-neoplastic female BECs and in neoplastic BECs expressing ERalpha. An association between these signaling pathways was demonstrated for female-predominant polycystic livers and might also influence autoimmune hepatitis, primary biliary cirrhosis, and cholangiocarcinogenesis. (HEPATOLOGY 2010.). less...

The progesterone receptor (PR) is a key regulator of female reproductive functions. Compounds with progesterone inhibiting effects (PR antagonists) have found numerous utilities in female reproductive health, ranging from contraception to potential treatment of progesterone dependent diseases like uterine leiomyomas. Based on in vitro characteristics such as DNA binding activity and partial agonistic transcriptional behavior in the presence of protein kinase A activators (cyclic-AMP), three types of PR modulators with antagonistic properties have been defined. In this study, we analyzed the in vitro characteristics of the PR antagonist ZK 230211 in comparison to the classical antagonists onapristone and mifepristone. We focused on PR actions in genomic signaling pathways, including DNA binding activity, nuclear localization and association with the nuclear receptor corepressor (NCoR) as well as actions in non-genomic signaling, such as the activation of c-Src kinase signaling and cyclin D1 gene promoter activity. ZK 230211 represents a type of PR antagonist with increased inhibitory properties in comparison to mifepristone and onapristone. When liganded to the progesterone receptor, ZK 230211 induces a strong and persistent binding to its target response element (PRE) and increases NCoR recruitment in CV-1 cells. Furthermore, ZK 230211 displays less agonistic properties with regard to the association of PR isoform B and the cytoplasmic c-Src kinase in HeLa cells. It represses T47D cell cycle progression, in particular estradiol-induced S phase entry. In summary, our studies demonstrate ZK 230211 to be a type III progesterone receptor antagonist which is characterized by very strong DNA binding activity and strong antiproliferative effects in the cancer cell lines HeLa and T47D. less...

Androgens appear to enhance whereas estrogens mitigate cardiac hypertrophy. However, signaling pathways in cells for short (3 minute) and longer-term (48 hour) treatment with 17beta-estradiol (E2) or 5alpha-dihydrotestosterone (DHT) are understudied. We compared the effect of adrenergic stimulation by norepinephrine (NE, 1 muM) alone or in combination with DHT (10nM) or E2 (10nM) treatment in neonatal rat ventricular myocytes (NRVMs) by cell area, protein synthesis, sarcomeric structure, gene expression, phosphorylation of extracellular signal-regulated (ERK) and focal adhesion (FAK) kinases, and phospho-FAK nuclear localization. NE alone elicited the expected hypertrophy, and strong sarcomeric organization, DHT alone gave a similar but more modest response whereas E2 did not alter cell size. Effects of NE dominated when used with either E2 or DHT with all combinations. Both sex hormones alone rapidly activated FAK but not ERK. Long-term or brief exposure to E2 attenuated NE-induced FAK phosphorylation whereas DHT had no effect. Neither hormone altered NE-elicited ERK activation. Longer-term exposure to E2 alone reduced FAK phosphorylation and reduced nuclear phospho-FAK whereas its elevation was seen in the presence of NE with both sex hormones. The mitigating effects of E2 on NE-elicited increase in cell size and hypertrophic effect of DHT in NRVMs are in accordance with results observed in whole animal models. This is the first report of rapid, non-genomic sex hormone signaling via FAK activation and altered FAK trafficking to the nucleus in heart cells. Key words: nuclear cytoplasmic shuttle, focal adhesion kinase, sarcomere organization, rapid hormone response. less...

BACKGROUND: The high morbidity and mortality of breast cancer among women is a serious problem. The adverse effects of the consumption of beef with zeranol (Z, a growth promoter widely used in beef industry in North American) residue on human health are still unknown. MATERIALS AND METHODS: The effects of Z implantation on the growth of heifer pre-adipocytes were evaluated. The stimulatory effects of Z and estradiol-17beta (E(2)) on the proliferation of pre-adipocytes isolated from control heifers and Z-implanted heifers were measured. Real-time PCR and Western-blotting analysis were performed to evaluate the expression of cyclin D1 and p53 at both mRNA and protein levels. RESULTS: The growth of pre-adipocytes from heifers bearing for 2 months of Z-implants was about 12-fold faster than that observed in control heifers. The pre-adipocytes isolated from Z-implanted heifers were more sensitive to treatment with Z and E(2). Z up-regulated the expression of cyclin D1 and down-regulated p53 in pre-adipocytes isolated from Z-implanted heifers. CONCLUSION: The implantation of Z increases body weight gain by enhancing growth of pre-adipocytes. The stimulation of pre-adipocytes division by Z and E(2) might be partially mediated by up-regulation of cyclin D1 and down-regulation of p53 at mRNA and protein levels. less...

17alpha-Ethynylestradiol (EE2), a major constituent of many oral contraceptives, is similar in structure to 17beta-estradiol, which has neuroprotective properties in several animal models. This study explored the potential neuroprotective actions of EE2 against kainic and quinolinic acid toxicity in the hippocampus of adult ovariectomized Wistar rats. A decrease in the number of Nissl-stained neurons and the induction of vimentin immunoreactivity in astrocytes was observed in the hilus of the dentate gyrus of the hippocampus after the administration of either kainic acid or quinolinic acid. EE2 prevented the neuronal loss and the induction of vimentin immunoreactivity induced by kainic acid at low (1 mug/rat) and high (10-100 mug/rat) doses and exerted a protection against quinolinic acid toxicity at a low dose (1 mug/rat) only. These observations demonstrate that EE2 exerts neuroprotective actions against excitotoxic insults. This finding is relevant for the design of new neuroprotective estrogenic compounds. less...