Reprod Toxicol. 2003 Jan-Feb;17(1):79-86.
Preimplantation mouse embryo development as a target of the pesticide methoxychlor.
Amstislavsky SY, Kizilova EA, Eroschenko VP, Amstislavksy SY.
Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Division, Novosibirsk State University, Novosibirsk, Russia.
Effects of methoxychlor (MXC) and estradiol-17beta (E) were studied in mouse preimplantation embryos. Pregnant mice received s.c. injections of sesame oil only, 10 microg E, or 0.5 mg purified (95%) MXC on Days 2-4 of pregnancy (plug = Day 1). Another group received a single dose of 2.5 microg E on Day 2 only. Based on the average weight of pregnant females, 10 microg of estradiol was equivalent to 0.33 mg/kg of bw, 2.5 microg of estradiol was equivalent to 0.082 mg/kg of bw, and the 0.5-mg dose of MXC was equivalent to 16.5 mg/kg of bw. All embryos were collected for analyses on Day 4. MXC and both estradiol-17beta doses suppressed embryonic development to blastocyst, decreased embryo cell numbers, and caused abnormal blastocyst formation. The high estradiol-17beta dose significantly increased the percent degenerating embryos and caused a tube-locking effect, with retention of embryos in the oviduct. In contrast to estradiol-17beta, MXC at the dose used in this study did not alter tubal transport of embryos. Also in contrast to estradiol-17beta, MXC increased the percentage of nuclear fragmentation and micronuclei. In preimplantation embryos, MXC and estradiol-17beta both suppressed embryo development. MXC effects were, however, different from those of estradiol-17beta, indicating a difference in mechanism of action, possibly due to cytotoxicity and induction of apoptosis. Copyright 2002 Elsevier Science Inc.
Reprod Biomed Online. 2003 Jun;6(4):452-5.
Do basal oestradiol and oestradiol:androgens and oestradiol:FSH ratios reflect pregnancy potential of women receiving intrauterine insemination during natural cycles?
Fukuda M, Fukuda K, Yding Andersen C, Byskov AG.
M&K Health Institute, Section of Human Reproductive Health, 30-9 Kariya, Ako, Hyogo 678-0239, Japan. fukuda876em.bekkoame.ne.jp
The aim of this retrospective study was to evaluate whether basal hormone profiles could be related to the ability to achieve pregnancy in women receiving intrauterine insemination (IUI) treatment during their natural menstrual cycle. Serum hormone profiles on cycle day 3 of naturally menstruating women were assessed in a total of 163 treatment cycles (29 conceptional and 53 non-conceptional cycles of 27 women who became pregnant and 81 non-conceptional cycles of 33 women who did not become pregnant). Basal concentrations of LH, FSH and prolactin were similar between conceptional and non-conceptional cycles. In contrast, concentrations of oestradiol in conceptional cycles (38 +/- 26 pg/ml: mean +/- SD) were significantly higher than those in non-conceptional cycles (23 +/- 18 pg/ml) (P = 0.0003). Concentrations of androstenedione and testosterone were lower but not significantly so in conceptional cycles as compared with non-conceptional cycles. The ratios of oestradiol/androstenedione, oestradiol/testosterone and oestradiol/FSH were significantly higher in conceptional as compared with non-conceptional cycles (29, 2.3, 6.2 versus 17, 1.2, 3.6 respectively) (all P < 0.006). Thus, increased concentrations of oestradiol and increased oestradiol/androgens and oestradiol/FSH ratios already on day 3 of the natural menstrual cycle correlate with the likelihood of achieving conception during the following IUI treatment. Therefore, measurement of basal hormones, including androstenedione and testosterone, may be useful to assess the health status of the coming dominant follicle.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12831593&dopt=Abstract estradiol [PubMed - i
J Neuroendocrinol. 2003 Aug;15(8):749-53.
Short-term effect of oestradiol on neurokinin B mRNA expression in the infundibular nucleus of ewes.
Pillon D, Caraty A, Fabre-Nys C, Bruneau G.
UMR 6073 Physiologie de la Reproduction et des Comportements, INRA/CNRS/Universite Francois Rabelais de Tours, Nouzilly, France.
In sheep, essentially all the neurokinin B (NKB) neurones of the infundibular nucleus express oestradiol receptor alpha, and analysis of female and male brains has revealed an exceptionally marked female-dominant sex difference in the numbers of NKB neurones in the infundibular nucleus. This neuronal population is located in an oestradiol-sensitive brain area involved in the control of gonadotropin-releasing hormone (GnRH) secretion and oestrous behaviour, but its physiological role is poorly documented. The aim of the present study was to analyse NKB mRNA expression at a crucial time when the steroid has stimulated the pathways leading to the induction of these two events. After cloning a specific ovine NKB antisense riboprobe, we examined the effects of a short oestradiol treatment (4 h subcutaneously) on the expression of NKB mRNA in the caudal part of the infundibular nucleus of progesterone-primed ovariectomized ewes. We demonstrated that oestradiol decreased both the level of NKB mRNA expression (34%) and the number of cells containing NKB mRNA (43%). Oestradiol acts strongly on these NKB cells in the short term. We suggest that this early change in NKB mRNA expression during the preovulatory period might be involved in the control of the induction of GnRH secretion or oestrous behaviour.
Brain Res. 2003 Jul 18;978(1-2):185-93.
Immediate and residual effects of tamoxifen and ethynylestradiol in the female rat hypothalamus.
Patisaul HB, Aultman EA, Bielsky IF, Young LJ, Wilson ME.
NSF Center for Behavioral Neuroscience, Emory University, Atlanta, GA 30329, USA. hbeaupmory.edu
Very little is known about the impact of selective estrogen receptor modulators (SERMs) on the brain. We examined the effects of tamoxifen (TAMOX) and the synthetic estrogen 17alpha-ethynylestradiol (EE) on estrogen-dependent gene expression and receptor binding in the female rat brain. Both immediate and residual effects were examined in both the presence and absence of 17beta-estradiol. Two groups of adult, ovariectomized, female rats (n=30 per group) were injected with TAMOX (5 mg/kg), EE (0.1 mg/kg), or sesame oil daily for 14 days. Animals from the first group were implanted with blank or 17beta-estradiol Silastic capsules concurrently with the last three SERM injections (immediate, group 1). Animals from the second group received either blank or 17beta-estradiol implants 2 weeks after the last injection (residual, group 2). All animals were sacrificed 72 h after implantation. TAMOX increased uterine weight in the absence of estrogen, but inhibited uterine weight gain in the presence of estrogen in both groups 1 and 2. TAMOX and EE increased oxytocin receptor binding in the ventromedial nucleus of the hypothalamus (VMN) in the absence of estrogen in both groups 1 and 2. The estrogen-dependent induction of PR mRNA expression in the VMN was significantly attenuated by TAMOX in group 1. Finally, TAMOX and EE had opposite effects on ERbeta mRNA expression in the paraventricular nucleus in the absence of 17beta-estradiol in group 1. Neither had any effect in group 2 when 17beta-estradiol was present. These results suggest that TAMOX has mixed agonist/antagonist effects in the female rat brain, many of which persist at least 2 weeks after the administration ceases.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12834913&dopt=Abstract estradiol [PubMed - index
Mol Reprod Dev. 2003 Aug;65(4):420-8.
Degree of sex reversal as related to plasma steroid levels in genetic female chickens (Gallus domesticus) treated with Fadrozole.
Vaillant S, Guemene D, Dorizzi M, Pieau C, Richard-Mercier N, Brillard JP.
Institut Jacques Monod, UMR 7592, C.N.R.S. et Universites Paris 6 et 7, Paris Cedex 05, France.
The objectives of this work were to determine whether or not plasma levels of testosterone and estradiol reflect the various grades of sex reversal in genetic female chickens treated with Fadrozole (CGS 16949 A), a nonsteroidal aromatase inhibitor, and whether gonadal aromatase activity and plasma levels of testosterone and estradiol in treated females can or not be modified by post-hatch treatments with Fadrozole or Fadrozole + testosterone. Eggs were injected with 1 mg Fadrozole on day 4 of incubation. In females having developed sex-reversed gonads, endocrine parameters (estradiol and testosterone) at and after 13 weeks of age were indicative of the degree of sex reversal, with, for example, sex-reversed females with two testes having the highest levels of testosterone and the lowest levels of estradiol. Among these females, eight (from a total of 13) produced ejaculates with scarce and abnormal spermatozoa. Some motility was observable in the ejaculates from five of them. None of the post-hatch treatments had a significant effect on plasma levels of testosterone or estradiol (measured at 3-week intervals from week 4 to week 28 post-hatch) or on gonadal aromatase activity (measured at 12 and 28 weeks). In conclusion, these results indicate that plasma levels of testosterone and estradiol at and after 13 weeks of age are valuable indicators of the degree of sex reversal in female chickens treated with Fadrozole prior to gonadal sex differentiation. In pre-cited conditions, post-natal treatments with either Fadrozole or Fadrozole + testosterone had no apparent effect on the degree of sex reversal in these birds. Finally, the occurrence of ejaculates with
Biol Psychiatry. 2003 Jul 1;54(1):59-69.
Influence of estradiol, stress, and 5-HT2A agonist treatment on brain-derived neurotrophic factor expression in female rats.
Cavus I, Duman RS.
Division of Molecular Psychiatry, Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, Yale University School of Medicine, New Haven, Connecticut, USA.
BACKGROUND: Estradiol affects neuronal plasticity, mood, and cognition. We examined the effects of the estrous cycle, acute and chronic estradiol treatments on BDNF mRNA expression in the hippocampus and cortex of female rats. The roles of 5-HT2A receptors and of stress on the BDNF mRNA regulation were also explored. METHODS: BDNF mRNA levels were measured using in situ hybridization at proestrus and estrus, and following acute and chronic estradiol treatment of acutely and chronically ovariectomized (OVX) female rats. Some rats were pretreated with 5-HT2A agonist and antagonist, and another group was subjected to two-hour immobilization stress. RESULTS: BDNF mRNA levels in the dentate gyrus and the medial prefrontal cortex were decreased during estrus, when estradiol levels are highest. Acute estradiol treatment decreased hippocampal BDNF mRNA in acutely OVX rats, but neither acute nor chronic estradiol had effect in chronically OVX rats. Estradiol pretreatment reduced the 5-HT2A receptor-mediated cortical upregulation in BDNF mRNA and did not effect the stress-induced down-regulation of BDNF mRNA in the dentate gyrus. CONCLUSIONS: The duration of the estradiol treatment and the duration of the ovarian hormone deprivation are important factors in the regulation of BDNF synthesis and possibly in the functional outcome of estrogen treatment.
Psychopharmacology (Berl). 2003 Nov;170(2):132-9. Epub 2003 Jul 04.
Effects of olanzapine infusions to the ventral tegmental area on lordosis and midbrain 3alpha,5alpha-THP concentrations in rats.
Frye C, Seliga A.
Department of Psychology, The University at Albany-SUNY, 1400 Washington Avenue, Albany, NY 12222, USA. cafrynsunix.albany.edu
RATIONALE: The progesterone metabolite and neurosteroid 5alpha-pregnane-3alpha-ol-20-one (3alpha,5alpha-THP) facilitates sexual behavior of estradiol-primed rodents through its actions in the ventral tegmental area (VTA). Olanzapine, an atypical antipsychotic, may exert some of its actions by increasing 3alpha,5alpha-THP levels. OBJECTIVE: If olanzapine has effects by increasing 3alpha,5alpha-THP levels, then olanzapine administration to the VTA should facilitate feminine sexual behavior of estradiol-primed rodents concomitant with increasing midbrain levels of 3alpha,5alpha-THP. METHODS. In experiment 1, ovariectomized rats with bilateral cannulae to the VTA were primed with estradiol at 0 h, infused with olanzapine (10 or 20 microg) or vehicle at 47 h, and tested for sexual behavior at 47.5 h. In experiment 2, estradiol-primed ovariectomized rats were infused with olanzapine (10 microg) or vehicle, tested for sexual behavior, then tissues were collected for measurement of midbrain progesterone and 3alpha,5alpha-THP, and plasma corticosterone, progesterone, and 3alpha,5alpha-THP. In experiment 3, estradiol-primed, ovariectomized rats were administered progesterone (500 microg, SC), tested for sexual behavior, then tissues were collected for midbrain and plasma progesterone and 3alpha,5alpha-THP levels. RESULTS: Infusions of 10 or 20 microg olanzapine to the VTA significantly increased the incidence and intensity of lordosis, and the occurrence of proceptive and aggressive behaviors. Rats infused with olanzapine to the VTA had significantly greater levels of midbrain 3alpha,5alpha-THP than did vehicle-administered rats. Olanzapine did not increase progesterone or corticosterone l
Clin Sci (Lond). 2003 Dec;105(6):663-9.
Effect of menstrual cycle phase on the concentration of bioavailable 17-beta oestradiol and testosterone and muscle strength.
Elliott KJ, Cable NT, Reilly T, Diver MJ.
Department of Sport and Exercise Sciences, University of Brighton, Eastbourne BN20 7SP, UK. k.j.elliotrighton.ac.uk
To investigate the effect of changes in sex hormone concentration on muscle strength and the bioavailability of 17-beta oestradiol (oestradiol) and testosterone, seven eumenorrheic females were tested during two phases of the menstrual cycle. Maximum voluntary isometric strength of the first dorsal interosseus muscle was measured during the early follicular and mid-luteal phases of the menstrual cycle. These phases were chosen for testing as the concentration of total oestradiol is significantly different in these two phases. Total oestradiol has been repeatedly associated with changes in muscle strength in females, whereas the effects of bioavailable oestradiol are unknown. The concentrations of total and bioavailable oestradiol and testosterone were measured in addition to the concentration of total progesterone. Concentrations of total progesterone and oestradiol were significantly different between the early follicular and mid-luteal phases of the menstrual cycle (P <0.05 and P <0.001 respectively). The concentration of total testosterone (0.7+/-0.2 and 0.8+/-0.1 nmol.l(-1) respectively) and the ratio of total oestradiol to progesterone (153.0+/-251.2 and 108.5+/-27.8 respectively) did not change significantly between the early follicular and mid-luteal phases. Bioavailable testosterone (102.2+/-66.3 and 105.0+/-90.2 pmol.l(-1) respectively) and bioavailable oestradiol (90.5+/-35.5 and 120.0+/-60.6 pmol.l(-1) respectively) did not differ significantly between phases. There were no significant differences in muscle strength during the menstrual cycle (P =0.1). Mean maximum voluntary isometric force of the first dorsal interosseus muscle did not correlate signif
Reprod Biol Endocrinol. 2003 Jun 21;1(1):50.
Ovarian follicular activity and hormonal profile during estrous cycle in cows: the development of 2 versus 3 waves.
Department of Theriogenology, Faculty of Veterinary Medicine, Alexandria University, Egypt. wnoseisn.com
Most estrous cycles in cows consist of 2 or 3 waves of follicular activity. Waves of ovarian follicular development comprise the growth of dominant follicles some of which become ovulatory and the others are anovulatory. Ovarian follicular activity in cows during estrous cycle was studied with a special reference to follicular waves and the circulating concentrations of estradiol and progesterone. Transrectal ultrasound examination was carried out during 14 interovulatory intervals in 7 cows. Ovarian follicular activity was recorded together with assessment of serum estradiol and progesterone concentrations. Three-wave versus two-wave interovulatory intervals was observed in 71.4% of cows. The 3-wave interovulatory intervals differed from 2-wave intervals in: 1) earlier emergence of the dominant follicles, 2) longer in length, and 3) shorter interval from emergence to ovulation. There was a progressive increase in follicular size and estradiol production during growth phase of each wave. A drop in estradiol concentration was observed during the static phase of dominant anovulatory follicles. The size of the ovulatory follicle was always greater and produced higher estradiol compared with the anovulatory follicle. In conclusion, there was a predominance of 3-wave follicular activity that was associated with an increase in length of interovulatory intervals. A dominant anovulatory follicle during its static phase may initiate the emergence of a subsequent wave. Follicular size and estradiol concentration may have an important role in controlling follicular development and in determining whether an estrous cycle will have 2 or 3-waves.
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