[CHANGES IN THE BRAIN TESTOSTERONE METABOLISM AND SEXUAL BEHAVIOR IN MALE RATS PRENATALLY EXPOSED TO METHYLDOPA AND STRESS].

The changes of aromatase and 5α-reductase activities were studied in preoptic area (POA) and medial basal hypothalamus of 10-days-old and sexual behavior in 3-month-old male offsprings of rats exposed daily to noradrenaline antagonist methyldopa (400 mg/kg per os) 30 minutes prior to 1-hour immobilization during the last week of pregnancy (from 15th to 21st day). Prenatal stress caused aromatase activity lowering in the POA of developing brain and feminization (appearance of lordosis) and demasculinization of sexual behavior (prolongation of latent periods to the first mounting and first intromission as well as of the first ejaculation and postejaculation refractory period) in young male offspring. Oral methyldopa used prior to pregnant females stressing prevented early effect of prenatal stress on aromatase activity in the POA and normalized the male sexual behavior in young male rats by shortening both latent period to the first ejaculation and postejaculation refractory period, and an increase of numbers of ejaculation. The data obtained indicate that brain noradrenergic system plays significant role in the mechanisms of metabolic- and behavioral disturbances developing in male rats exposed to prenatal stress.

Reversibility of endocrine disruption in zebrafish (Danio rerio) after discontinued exposure to the estrogen 17α-ethinylestradiol.

The aim of the present study was to investigate the persistence of the feminizing effects of discontinued 17α-ethinylestradiol (EE2) exposure on zebrafish (Danio rerio). An exposure scenario covering the sensitive phase of sexual differentiation, as well as final gonad maturation was chosen to examine the estrogenic effects on sexual development of zebrafish. Two exposure scenarios were compared: continuous exposure to environmentally relevant concentrations (0.1-10 ng/L EE2) up to 100 days post-hatch (dph) and developmental exposure up to 60 dph, followed by 40 days of depuration in clean water. The persistence of effects was investigated at different biological organization levels from mRNA to population-relevant endpoints to cover a broad range of important parameters. EE2 had a strong feminizing and inhibiting effect on the sexual development of zebrafish. Brain aromatase (cyp19b) mRNA expression showed no clear response, but vitellogenin levels were significantly elevated, gonad maturation and body growth were inhibited in both genders, and sex ratios were skewed towards females and undifferentiated individuals. To a large extent, all of these effects were reversed after 40 days of recovery, leading to the conclusion that exposure to the estrogen EE2 results in very strong, but reversible underdevelopment and feminization of zebrafish. The present study is the first to show this reversibility at different levels of organization, which gives better insight into the mechanistic basis of estrogenic effects in zebrafish.

Neuroprotection with non-feminizing estrogen analogues: an overlooked possible therapeutic strategy.

Although many of the effects of estrogens on the brain are mediated through estrogen receptors (ERs), there is evidence that neuroprotective activity of estrogens can be mediated by non-ER mechanisms. Herein, we review the substantial evidence that estrogens neuroprotection is in large part non-ER mediated and describe in vitro and in vivo studies that support this conclusion. Also, we described our drug discovery strategy for capitalizing on enhancement in neuroprotection while at the same time, reducing ER binding of a group of synthetic non-feminizing estrogens. Finally, we offer evidence that part of the neuroprotection of these non-feminizing estrogens is due to enhancement in redox potential of the synthesized compounds.

Ultra-high performance liquid chromatography/tandem mass spectrometry determination of feminizing chemicals in river water, sediment and tissue pretreated using disk-type solid-phase extraction and matrix solid-phase dispersion.

This study developed and validated a method of measuring the feminizing chemicals 4-tert-octylphenol, 4-nonylphenol, nonylphenol monoethoxycarboxylate (NP(1)EC), nonylphenol monoethoxylate (NP(1)EO), nonylphenol diethoxylate (NP(2)EO), estrone, 17ß-estradiol, estriol, 17α-ethinyl estradiol and bisphenol A in river water, sediment, and tissue using ultra-high performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) and isotope-dilution techniques. Water samples were pretreated using disk-type automated solid-phase extraction (SPE). Solid samples of sediment, fish, and clams were treated with matrix solid-phase dispersion (MSPD) using C(8) adsorbent. Eluents were directly passed following alumina cartridges for cleanup. The signal intensity of analytes on electrospray ionization (ESI) was compared with that of atmospheric pressure photoionization (APPI). The analytes were separated on a UHPLC C(18) column with aqueous 10-mM ammonium acetate for NPEOs and aqueous 10-mM N-methylmorpholine for the other compounds. On-line cleanup was evaluated using two-dimensional liquid chromatography (2-D LC). ESI could provide satisfactory response for all of the analytes. Though APPI did not offer suitable response for NP(1)EO, NP(2)EO and NP(1)EC, it provided better signal intensities for the steroid estrogens (1.0-2.4 times) and the phenols (3.2-4.4 times) than ESI. UHPLC shortened chromatographic time to less than 10 min. Disk-type automated SPE and MSPD dramatically increased the throughput of sample preparation. The extraction efficiency on surface water samples ranged from 10% to 91%. The extraction efficiency of MSPD on sediment, fish, and clams was 51-101%, 36-109%, and 30-111%, respectively. Acidic alumina cleanup was essential for the analysis of the tissue sample, and reduced matrix effects better than 2-D LC on-line cleanup. The limits of detection (LODs) in water ranged from 0.81 ng/L to 89.9 ng/L. The LODs in sediment and tissue ranged from tens of pg/g wet weight to only a few ng/g wet weight. This method proved to be accurate and reproducible, as both quantitative biases and relative deviations remained smaller than 20% at three spiked levels.

[Effect of tamoxifen on the feminization of chick embryo testis]. / Action du tamoxifène sur la féminisation du testicule embryonnaire de poulet.

The problem was approached whether the feminizing action of oestrogens or androgens on the chick embryo testes could be antagonized by anti-oestrogens or anti-androgens. 100 micrograms of either tamoxifen, cyproterone acetate or compound RU 23908 were injected into the chick embryo after 4 days of incubation and 100 micrograms of either oestradiol benzoate or diethylstilboestrol or 1 mg of either androsterone, dehydroepiandrosterone, 5 alpha-dihydrotestosterone or 5 alpha-androstanedione were given one day later. The surviving embryos were sacrificed when 14-17 days old and their gonads were examined morphologically and in some cases also histologically. Control embryos were only given oestrogens or androgens. Out of 20 surviving embryos treated with oestradiol only, 10 were genetic females and 10 strongly feminized males. After tamoxifen treatment, out of 20 embryos, 11 were females, 7 normal males and 2 slightly feminized males. Thus, tamoxifen suppressed the feminizing action of oestradiol. It antagonized also the feminizing action of diethylstilboestrol. Neither cyproterone acetate nor compound RU 23908 suppressed the feminizing action of androsterone or diethylstilboestrol. But tamoxifen interfered with the androgens, preventing the feminization of the testes. It is suggested that androgens bind to the oestrogen receptor.

Prevention of demasculinization and feminization of the brain in prenatally stressed male rats by perinatal androgen treatment.

Female rats were exposed to immobilization and illumination stress from day 15-22 of pregnancy. Their male offspring showed demasculinization, i.e. significantly decreased male sexual behaviour, and feminization, i.e. significantly increased female sexual behaviour, in adulthood. This permanent demasculinization and feminization of the brain, induced by prenatal stress, could be prevented by perinatal androgen treatment.

Digoxin does not alter plasma steroid levels in health men.

Digoxin has been reported to induce feminizing effects in man. It does not compete for estradiol cytosol receptors in human breast carcinoma cells, however, and has no uterotrophic effect. We therefore investigated whether feminization might be due to digoxin action on plasma concentrations of sex steroids. Six healthy men (31.5 +/- 4 yr old) received therapeutic doses of digoxin for 43 days. We measured plasma concentrations of testosterone, androstenedione, dehydroepiandrosterone, estrone, estradiol, progesterone, 17-hydroxyprogesterone, cortisol, and aldosterone. During 35 days on digoxin levels of these steroids remained in the normal range and there was no change from before-drug values. Digoxin was in the therapeutic range of 1.9 +/- 3 nmol/l throughout. After stimulation by adrenocorticotropic hormone or human choriongonadotropin, the rise in plasma steroids was in the same range as when digoxin was given, as well as 16 wk after it had been discontinued. A normal rise in luteinizing hormone after luteinizing hormone-releasing hormone showed that the hypothalamogonadal feedback was not altered by digoxin. Free testosterone, estradiol, and cortisol concentrations under basal conditions and after stimulation were also the same before and after drug. It is concluded that the estrogen-like activity of digoxin cannot be explained by altered steroid availability from plasma. Feminizing effects attributed to digoxin may be caused by other conditions known to influence sex steroid hormones that are common in patients with heart disease. Our data suggest that digoxin may be the preferred digitalis therapy to avoid feminizing effects.