Citations
All
Search in:AllTitleAbstractAuthor name
Publications
(1K+)
Patents
Grants
Pathways
Clinical trials
Publication
Journal: Science of the Total Environment
November/19/2006
Abstract
Most studies of hormonal activity in rivers have focused on inputs from sewage treatment works (STW), and their consequences for endocrine disruption in fish. It is possible that livestock is contributing to this hormonal activity in rivers. This study represents a search for evidence of steroid hormone contamination in streams associated with livestock farms. The majority of the 10 sites selected were streams running through dairy farms, although some examples of beef, sheep and pigs were included. Passive water samplers (Polar Organic Chemical Integrative Samplers-POCIS) were deployed up- (control) and down-stream of the farms for 3 to 10 weeks (mean=39 days) during the period November 2004 to January 2005. At one site, water samples were also taken automatically during rainfall events. All samples were solvent-extracted. Total oestrogenic activity in concentrates of the extracts was analysed using the Yeast Estrogen Screen (YES) calibrated against 17beta-oestradiol (E2), while oestrone (E1), E2 and 17alpha-ethinylestradiol (EE2) were analysed by liquid chromatography-mass spectrometry (LC-MS/MS). Stream water from the entirety of only one rainfall event was sampled directly, but this revealed background activity (E2 equivalents) of 0-0.3 ng/l, rising to a transient peak of 9.4 ng/l. Average oestrogenic activity at this site as estimated from the POCIS samplers was 1.8-2.7 ng E2 equiv./l. Estimated average oestrogenic activity across all sites (with one exception) lay in the range 0-26.5 ng E2 equiv./l (mean=2.0 ng/l; S.D.=5.1), based on the POCIS samples. The outlier was 292 ng/l, and this could not be specifically linked with livestock rearing. 92% of monitoring stations (at least one on each farm) contained some oestrogenic activity, and activity was higher at downstream sites in 50% of cases. Although no EE2 was detected analytically in any stream, E1 and E2 were almost ubiquitous, with E2 equivalents ranging from 0.04 to 3.6 ng/l across all sites. Furthermore, steroid concentrations downstream of livestock were higher than upstream in 60% of cases, more markedly so than for the YES data. In several cases, activity upstream was greater than downstream, and this tended to be associated with higher activity than could be accounted for by the hormone analyses. Both the YES and chemical analytical data suggest that fish in headwater streams on or near some livestock farms may be at risk of endocrine disruption.
Publication
Journal: Maturitas
December/17/1979
Abstract
Cyclical regimens of unopposed oestrogens are associated with the development of endometrial hyperplasia and the incidence of hyperplasia is dose-related. As no pattern of vaginal bleeding serves as a reliable indicator of underlying endometrial pathology and as hyperplasia can develop subsequent to the finding of a normal endometrium and at any time from 2 to 35 mth after the start of treatment, serial biopsies are required on every patient. Oral oestrone and oestradiol complexes both give rise in the plasma principally to oestrone and therefore the term "Hormone replacement therapy" is inappropriate. The incidence of hyperplasia during sequential oestrogen/progestogen therapy is greatly reduced and therefore progestogens are capable of protecting against the development of this condition. Sequential regimens can also reverse oestrogen-related hyperplasia to normal endometrium.
Publication
Journal: British Journal of Cancer
September/10/1989
Abstract
The endocrine and therapeutic effects of the LHRH agonist Zoladex have been assessed in 28 post-menopausal women with advanced breast cancer. Fourteen had responded to previous hormone therapy and 14 had no previous hormone therapy. There were two partial responses and two patients with stable disease for more than 6 months in the former group, and one partial response and two with stable disease for more than 6 months in the latter group. Toxicity was minimal. All responses occurred in soft tissue. Six out of seven patients who received tamoxifen after progression of disease on Zoladex showed a response. Peripheral oestradiol levels were measured, and they fell after 1 month from 33 pmol l-1 (+/- 20, s.d.) to 22 pmol l-1 (+/- 11, s.d.) (P less than 0.005). Responders and non-responders showed similar changes in oestradiol. Oestrone levels did not change significantly. These results suggest that Zoladex acts indirectly via changes in peripheral hormones, rather than directly on LHRH receptors on the tumour.
Pulse
Views:
1
Posts:
No posts
Rating:
Not rated
Publication
Journal: Acta Endocrinologica
January/17/1973
Publication
Journal: Biochimica et Biophysica Acta - General Subjects
November/25/1969
Publication
Journal: The American journal of cancer
January/2/1980
Authors
Publication
Journal: Acta Endocrinologica
October/31/1998
Publication
Journal: The Lancet
August/22/1976
Abstract
Fifteen men who had had a myocardial infarction between the ages of 32 and 42 years were compared with fifteen age-matched healthy men. Seven of the patients had a strikingly slow rate of beard growth, three had evidence of gynaecomastia, and three had a loss of libido. The slow beard growth and decreased libido, and possibly the gynaecomastia, preceded the myocardial infarction. Mean serum oestradiol and oestrone concentrations were significantly increased in the patients, 43.5 +/- 8.8 (standard deviation) and 50.7 +/- 9.5, respectively, compared wth 33.5 +/- 5.5 and 37.5 +/- 5.8 pg/ml in the controls (p less than 0.001). Mean serum testosterone and dihydrotestosterone concentrations were not significantly different in the two groups. Serum oestradiol and oestrone concentrations were directly proportional to each other as were those of testosterone and dihydrotestosterone. These results suggest that the hyperoestrogenaemia preceded the myocardial infarction and that hyperoestrogenaemia may be an important risk factor for myocardial infarction in men.
Publication
Journal: Andrology
June/1/2014
Abstract
Phosphodiesterase-5-inhibitors, such as sildenafil, increase intracavernosal cyclic guanosine monophosphate levels, which results in corporal smooth muscle relaxation and penile erection. Here, we determined the effects of sildenafil administration on the hypothalamic-pituitary-gonadal axis in men with erectile dysfunction and low testosterone levels. The Testosterone and Erectile Dysfunction trial (ClinicalTrials.gov # NCT00512707) initially administered an optimized dose of sildenafil to 140 men, aged 40-70 years with erectile dysfunction, low serum total testosterone (<11.4 nmol/L; 330 ng/dL) and/or free testosterone (<173 pmol/L; 50 pg/mL) over 3-7 weeks. Sex steroids and gonadotropins were measured at baseline and after sildenafil optimization in a longitudinal study without a separate control group. Serum testosterone, dihydrotestosterone (DHT) and oestrogens were measured using liquid chromatography-tandem mass spectrometry. Administration of an optimized dose of sildenafil was associated with mean increases of 3.6 nmol/L (103 ng/dL; p < 0.001) and 110 pmol/L (31.7 pg/mL; p < 0.001) in total and free testosterone levels respectively. This was accompanied by parallel increases in serum DHT (0.17 nmol/L; 4.9 ng/dL; p < 0.001) and oestradiol (14 pmol/L; 3.7 pg/mL; p < 0.001) and significant suppression of luteinizing hormone (change -1.3 units/L; p = 0.003) levels, suggesting a direct effect at the testicular level. Androstenedione and oestrone increased by 1.3 nmol/L (38 ng/dL; p = 0.011) and 10.7 pmol/L (2.9 pg/mL; p = 0.012), respectively, supporting a possible effect of sildenafil on adrenal steroidogenesis. In conclusion, sildenafil administration was associated with increased testosterone levels likely ascribable to a direct effect on the testis.
Publication
Journal: Gut
October/28/1976
Abstract
A highly specific radioimmunoassay was used to measure the total plasma concentrations of the three principal unconjugated oestrogens: oestrone E1, oestradiol E2, and oestriol E3 in normal males and in 21 males with various forms of chronic liver disease. In addition, the unbound concentration of plasma E2 was established in the same group. About half of the patients with liver disease had overt feminising changes. Total and unbound plasma E2 concentrations were within the normal range in all patients. Total plasma E1 was significantly elevated only in those patients with liver disease and gynaecomastia, and a similar trend was seen for total plasma E3.
Publication
Journal: British Journal of Cancer
December/16/1983
Abstract
Eighty-one postmenopausal women with advanced breast cancer were studied for the effects of treatment with aminoglutethimide (AG) plus hydrocortisone on peripheral hormones and response to therapy. There were 40 responders (R) and 41 non-responders (NR) at 3 months from the start of treatment. Plasma oestrone concentrations were higher in non-responders at 1 and 2 months after starting AG (Means: NR 106 +/- 50, R 84 +/- 26 pmol l-1, P less than 0.05; highest value NR 121 +/- 51, R 99 +/- 24 pmol l-1, P less than 0.05). High oestrone levels were correlated with bulky liver secondaries, but not with age, tumour-free interval, time from last menstrual period, time from relapse to start of AG or body weight. Non-responders had higher mean prolactin levels on treatment (prolactin less than 500 mIUl-1 in 14/40 NR, 2/35 R, P less than 0.01). High oestrone or prolactin levels were present in 28/41 NR and 6/40 R (P less than 0.001). Dehydroepiandrosterone sulphate suppression did not differ between R and NR. The differences in peripheral endocrine environment in non-responding patients suggest that oestrogen metabolism may differ in non-responding patients and that sub-groups could be selected for rational endocrine therapy.
Publication
Journal: European Journal of Cancer
March/31/1997
Abstract
We studied the clinical and endocrine effects of the aromatase inhibitor formestane (4-hydroxyandrostenedione, 4-OHA) in heavily pretreated breast cancer patients (median number of previous endocrine treatments 2, range 1-4). Of 30 patients eligible for response evaluation, 3 patients (10%) showed a partial response while 11 patients (36.7%) experienced stable disease over a time period of at least 6 months. Plasma levels of oestrone, oestradiol and oestrone sulphate were found suppressed to a mean of 33.9, 35.6 and 24.2% of control values. 4 of 6 patients experienced a further substantial reduction in plasma oestrone sulphate to < 5% of pretreatment values when aminoglutethimide (AG) was added after relapse on 4-OHA monotherapy. Our findings suggest that these aromatase inhibitors may suppress plasma oestrogen levels by a percentage approaching the percentage inhibition of in vivo aromatisation measured by tracer techniques.
Publication
Journal: Journal of Steroid Biochemistry and Molecular Biology
July/18/1994
Abstract
Oestradiol 17 beta-hydroxysteroid dehydrogenase (E2DH) has a pivotal role in the regulation of oestradiol (E2) concentrations in normal and malignant breast tissues. Previous studies have suggested that a number of cytokines can stimulate E2DH activity to increase the conversion of oestrone (E1) to E2. In this investigation we have examined the effect of TNF alpha, interleukin-1 beta (IL-1 beta) and IL-6 on E2DH activity in MCF-7 breast cancer cells. These cytokines may be produced by breast tumours and their presence in conditioned medium (CM) from tumour-derived fibroblasts was also measured to assess their possible contribution to its E2DH stimulatory activity. Treatment of MCF-7 cells with IL-1 beta and TNF alpha (5 ng/ml) significantly increased (P < 0.001) reductive E2DH (red-E2DH, the conversion of E1 to E2) activity. In contrast, IL-6 at a concentration of 100 ng/ml produced little, if any, stimulation of reductive activity. Combinations of all three cytokines acted synergistically to stimulate red-E2DH activity. No cytokine, either alone or in combination, affected oxidative (E2->>E1) activity. Significant concentrations of IL-6 and IL-1 beta were detected in CM, but the stimulation of red-E2DH activity was much greater than that which could be explained by their levels alone. It is concluded that these cytokines may play an important role in regulating E2DH activity in breast cancer cells and may act synergistically in vivo to enhance the formation of E2 in breast tumours.
Publication
Journal: Biochemical Journal
April/7/1975
Abstract
The specificity of the binding of oestradiol-17beta by cytoplasmic fractions of several tissues of the male rat was investigated. 1. Agar-gel electrophoresis, Sephadex chromatography, adsorption by dextran-coated charcoal and sucrose-gradient centrifugation were used to estimate the binding capacity and specificity. The four different methods all gave similar results for the capacity of the specific oestradiol-17beta-binding macromolecules in the testis. 2. The presence of a specific saturable binding protein with a sedimentation coefficient of 8S was demonstrated in liver, adrenal, pituitary, prostate, epididymis and testis interstitial tissue. The highest concentration of oestradiol-17beta-binding macromolecules was found in testis interstitial tissue (0.12pmol/mg of protein) and in the pituitary (0.075pmol/mg of protein). 3. The oestradiol-17beta receptor in the testis cytosol showed the characteristics of a protein with respect to Pronase treatment and temperature sensitivity. In competition experiments with different steroids the receptor showed a high affinity for oestradiol-17beta, a moderate affinity for diethylstilboestrol and oestradiol-17alpha and a low affinity for oestrone, oestriol, testosterone and 5alpha-dihydrotestosterone (17beta-hydroxy-5alpha-androstan-3-one). 4. The wide distribution of oestradiol-17beta receptors in the male rat is in apparent contradiction to the current concept of the specificity of steroid-hormone action. Further research is required to investigate a possible physiological meaning of the presence of specific receptors in the different tissues.
Publication
Journal: Journal of reproduction and fertility
October/25/1979
Abstract
Concentrations of LH/CG, androstenedione and testosterone rose in early pregnancy to maximum values at 6--10 weeks. Thereafter LH/CG levels declined and androstenedione and testosterone levels remained at plateau values or declined until term. Progesterone, oestradiol-17 beta and oestrone increased after ovulation and remained high throughout pregnancy. At 12 weeks, when LH/CG levels were falling, progesterone and oestradiol rose well above the luteal-phase levels which were maintained for the first 12 weeks. Progesterone declined in the 2 weeks before birth, while oestradiol and oestrone remained high. Pregnancies of an unknown stage were dated by reference to a graph of uterine diameter, measured by abdominal palpation, in animals at known times after conception. Measurement of progesterone concentrations during the conception cycle gave more accurate dating and showed that the gestation length was 144 days.
Publication
Journal: Journal of Neuroendocrinology
December/22/2005
Abstract
Previous results from our laboratory have shown that 17beta-oestradiol prevents 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) striatal dopamine depletion. 17beta-oestradiol, oestriol and oestrone are the naturally occurring oestogens in humans. Using various dopamine markers, the present study investigated whether oestrone and oestriol such as 17beta-oestradiol have neuroprotective activity in MPTP-treated mice. Male mice were treated with 17beta-oestradiol, oestriol or oestrone for 5 days before and after MPTP administration, and were compared with nonlesioned mice receiving the same treatment. Striatal concentrations of dopamine and its metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), were assayed by high-performance liquid chromatography. Dopamine transporter (DAT) and vesicular monoamine transporter (VMAT2) specific binding were measured by autoradiography. DAT, VMAT2 and tyrosine hydroxylase mRNA levels were measured by in situ hybridisation. MPTP induced a loss of DAT and VMAT2 specific binding in the striatum and substantia nigra, as well as a decrease of VMAT2 mRNA in the substantia nigra. 17beta-oestradiol treatment prevented the loss of these dopaminergic markers, as well as striatal concentrations of dopamine, DOPAC and HVA. Mice receiving oestriol and oestrone showed catecholamine concentrations comparable to MPTP mice. Oestriol treatment had no effect on dopaminergic markers in MPTP mice whereas oestrone prevented striatal DAT loss and the decrease of VMAT2 mRNA in the substantia nigra. In nonlesioned mice, 17beta-oestradiol, oestriol or oestrone had no effect on all the dopaminergic markers investigated. In conclusion, a weak or a lack of effect of oestriol and oestrone was observed compared to 17beta-oestradiol in MPTP mice and none of these steroids had an effect in nonlesioned mice. A DAT and VMAT2 specific binding decrease after MPTP in the striatum and substantia nigra, as well as a decrease of substantia nigra VMAT2 mRNA, was observed and could be prevented by oestradiol.
Publication
Journal: Paediatric and Perinatal Epidemiology
July/22/2007
Abstract
The Oxford Conception Study is a randomised controlled trial that aims to determine whether or not information about potential fertility from a device that monitors urinary hormones will increase the conception rate in women wishing to conceive. Three modified versions of a fertility monitor have been developed for the study. The monitor measures the levels of urinary oestrone-3-glucuronide (E3G) and luteinising hormone (LH), and the display indicates high or low fertility. The monitor requests all women to test their urine from day 6 to day 25 of the menstrual cycle inclusive. One-third of women are randomised to receive information from the fertility monitor about the early fertile time (from the first rise in E3G until the LH surge is detected), one-third receive information about the late fertile time (the onset of the LH surge and the following 2 days), and a third do not receive any information (control group). All the women are followed up for 6 months or until they are pregnant. A total of 1453 women have been recruited into the study, reaching the study recruitment goal for 80% power to detect a 10% difference in three-cycle pregnancy rate between the Late Fertile Time group (50%) and the Control group (40%), allowing for a 15% non-pregnancy drop-out rate. Follow-up of the women is currently ongoing. The primary analysis will compare the cumulative three-cycle pregnancy rate between each of the study arms. Time-specific conception probabilities will be estimated from coitus information recorded in 12-h intervals. The data from this study will also allow many additional questions to be addressed, including changes in intercourse patterns with feedback about the fertile days and other questions in relation to menstrual cycle function, sexual intercourse, stress, exposures to tobacco products, alcohol, caffeine and medications, fertility and pregnancy outcomes. In addition to presenting the study design, we review the recruitment experience for the Oxford Conception Study. We have achieved sustained and effective recruitment over time by primary use of recruiting via the Internet.
Publication
Journal: Biochemical Journal
August/31/1978
Abstract
Rabbit liver UDP-glucuronyltransferase activity was resolved into two separate fractions on DEAE-cellulose, one containing most of the transferase activity toward oestrone and the other most of the activity toward p-nitrophenol. These two activities were completely separated by rechromatography of each fraction on a second DEAE-cellulose column.
Publication
Journal: Acta Endocrinologica
December/17/1980
Abstract
Oestrogens, testosterone, and 5 alpha-androstenone ('boar taint steroid') were determined in peripheral and spermatic vein blood plasma of boars. Oestrone was the predominant steroid in both the conjugated and the unconjugated fractions of total oestrogens. Concentrations of conjugated oestrogens in peripheral plasma generally are in the range of several nanograms/ml, which is similar to the range of 5 alpha-androstenone and testosterone. Unconjugated total oestrogens are in the lower nanogram-range. These concentrations, however, are still higher than those during the oestrus in sows. Stimulation with hCG led to increased concentrations of peripheral plasma oestrogens, demonstrating their testicular origin. Comparative measurements in spermatic vein plasma and peripheral plasma show that in general the testis has to secrete different amounts of the individual steroid to maintain the appropriate peripheral level. A highly correlated course of all the steroids measured was apparent. This was shown for the diurnal rhythm, the age-related changes and for the increase after application of hCG.
Publication
Journal: Maturitas
May/25/1987
Abstract
To permit a more detailed hormonal characterization of the peri-menopause, 30 healthy women were examined at regular intervals over a 7-yr period, starting about 3 yr before the menopause. Even though most of the subjects periodically experienced climacteric symptoms, no hormonal supplementation was given. The serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), oestradiol and oestrone that were recorded essentially confirmed previous data obtained in cross-sectional studies. Within the 6-mth period around the menopause the serum levels of testosterone and androstenedione showed small but significant decreases of 18 and 16%, respectively. These decreases continued over the following years and amounted to about 30% after 3 yr. In contrast, neither the mean level of dehydroepiandrosterone (DHA) nor the DHA/DHA sulphate (DHAS) ratio changed significantly at the menopause, but DHA and DHAS concentrations declined slowly by about 20% over the 7-yr observation period. The mean level of DHAS showed an isolated increase during the last few months before the menopause. A similar, although not significant, increase was also seen in DHA and testosterone levels. After the first post-menopausal year a significant positive correlation was found between the levels of oestrone and androstenedione. This longitudinal study of individual women appeared to lend itself well to the investigation of even subtle hormonal fluctuations during the gradual transition to an established post-menopausal pattern.
Publication
Journal: European Journal of Cancer
October/31/2004
Abstract
The aromatase enzyme, which converts androstenedione to oestrone, regulates the availability of oestrogen to support the growth of hormone-dependent breast tumours. In this study, we investigated the inhibitory effects of black tea polyphenols on aromatase activities. We found that black tea polyphenols, TF-1, TF-2 and TF-3, significantly inhibited rat ovarian and human placental aromatase activities. In addition, using an in vivo model, these black tea polyphenols also inhibited the proliferation induced by 100 nM dehydroepiandrosterone (DHEA) in MCF-7 cells. Transfection of HER2/neu in MCF-7 breast cancer cells appeared to be associated with an increased resistance of the cells to hormonal therapy. Interestingly, unlike the selective oestrogen receptor modulator (SERM) tamoxifen, black tea polyphenols had antiproliferation effects in breast cancer cells with hormonal resistance. The inhibitory effect of black tea polyphenols on hormone-resistant breast cancer cells suppressed the basal receptor tyrosine phosphorylation in HER2/neu-overexpressing MCF-7 cells. These findings suggest the use of black tea polyphenols may be beneficial in the chemoprevention of hormone-dependent breast tumours and represent a possible remedy to overcome hormonal resistance of hormone-independent breast tumours.
Publication
Journal: Journal of Endocrinology
May/5/1974
Publication
Journal: Human Reproduction
September/7/1993
Abstract
Polycystic ovary syndrome is associated with hypersecretion of luteinizing hormone (LH) which has been implicated in the aetiology of early pregnancy loss. Although 82% of women with recurrent early loss have polycystic ovaries on ultrasound imaging, random serum LH concentrations are normal. In the present study, we have obtained further information from serial samples concerning the cyclical patterns of gonadotrophin and sex steroid secretion in these women. Twenty-one women with recurrent early pregnancy loss and 10 multiparous controls were investigated; 81% of them and one of ten control subjects had polycystic ovaries. Mean mid-follicular and mid-luteal serum LH and follicle stimulating hormone (FSH) levels were similar in both groups. Seventeen women with pregnancy loss had either raised urinary LH excretion or a premature LH surge; one control subject had a premature LH surge. Total LH excretion during the cycle and mean follicular phase serum testosterone was significantly greater with early pregnancy loss than in the control group, the difference in LH being greatest in the early luteal phase. Urinary oestrone-3-glucuronide excretion was raised in the early luteal phase of the cycle in the group with early pregnancy loss; there was no difference between the groups in pregnanediol-3 alpha-glucuronide excretion. These data demonstrate abnormalities in LH secretion in 81% of women with recurrent fetal loss. Inappropriately raised LH levels may have adverse effects on the developing oocyte or endometrium either directly, or indirectly by causing an elevation in testosterone and oestrogen levels.
Publication
Journal: Journal of reproduction and fertility
January/16/1991
Abstract
Reports on callitrichid monkeys have not revealed a significant effect of nursing on interbirth intervals or on post-partum to ovulation intervals. We examined 25 post-partum intervals in cotton-top tamarin females to determine whether nursing infants would affect the length of the post-partum to ovulation interval. Urinary LH/CG and oestrone conjugates were measured in urine samples collected in the 6 weeks after birth. The post-partum to ovulation interval is the number of days between parturition and the rise of urinary LH and oestrone conjugates associated with ovulation. There was an 84% conception rate post partum. Neither mother's parity nor sex of the infants influenced the length of the post-partum to ovulation interval. The post-partum to ovulation interval for females nursing 2 infants was twice as long as for those not nursing or nursing 1 infant (P less than 0.05). The range of post-partum to ovulation interval lengths was more variable in nursing than in non-nursing females (P less than 0.01). Females spent less than 50% of observed time in contact and less than 20% of observed time nursing their infants. Neither the number of tamarins within the family nor the amount of time the mother was in contact with infants correlated with the length of the post-partum to ovulation interval. However, there was a positive correlation between the percentage time that mothers nursed 1 infant at a time and the length of the post-partum to ovulation interval (r = 0.75, P less than 0.02). The underlying mechanisms of suckling-induced delay of ovulation are present in the cotton-top tamarin as in other primate species. However, these nursing effects do not cause the substantial delay in fertility post partum that is associated with non-callitrichid primates.
load more...