Effects of 17 beta-estradiol on serum hormone concentrations and estrous cycle in female Crl:CD BR rats: effects on parental and first generation rats

It has been proposed that short-term activation of the hypothalamo-pituitary adrenal axis, with a consequent increase in the secretion of cortisol, amy disrupt the endocrine events prior to ovulation and thereby impair reproduction in females. We investigated this concept in gilts in which oestrus was detected by introduction to boars, where intense physical contact is possible, or by applying pressure to the back of gilts (back-pressure test) during fence-line exposure to boars, where intense physical contact is prohibited. We expected that there would be a greater release of cortisol and that reproduction would be inhibited in gilts introduced to boars compared to gilts in which the back-pressure test was used. As expected, introduction of gilts to boars resulted in a significant transient increase in plasma concentrations of cortisol while there was no significant effect of using the back-pressure test on plasma cortisol. Nevertheless, introduction of gilts to boars did not impair reproduction and there was no effect of method of detecting oestrus on duration of oestrus, sexual receptivity, fertility or fecundity. The length of the oestrous cycle was decreased and ovulation rate increased in gilts that were introduced to boars compared to gilts that underwent the back-pressure test, indicating that introduction of gilts to boars may have stimulated these aspects of reproduction. These stimulatory effects may have been due to an increased exposure of gilts to sexual behaviour and stimuli from boars when introduced to boars and/or to stimulatory effects of the hypothalamo-pituitary adrenal axis on some aspects of reproduction.     

Multigeneration reproduction study of policosanol in rats

The objective of this study was to analyse the effects of isoflurane anesthesia (lasting for 15 or 60 min) and isoflurane anesthesia termination (after 1 or 24 h) on met-enkephalin (MENK) and leu-enkephalin (LENK) levels in discrete brain areas and spinal cord segments in rabbits. Moreover histochemical analysis of activities of succinate dehydrogenase, magnesium-dependent adenosine triphosphatase (Mg++ATP-ase) and acid phosphatase in the striatum and hypothalamus were carried out to evaluate the effects of isoflurane anesthesia on energetic, transport and catabolic processes. Throughout anesthesia (15 and 60 min) and after its termination (1 h) the LENK contents were increased in hypothalamus, hippocampus, mesencephalon and lumbar segment of spinal cord. Moreover, during isoflurane anesthesia and after its termination (1 h) MENK and LENK levels decreased in cervical segment and MENK content dropped in thoracic segment of spinal cord. Histochemical data indicated, that isoflurane enhanced energetic processes as well as exchange processes in neurocytes, glial cells, capillary walls and ependymal cells of the third ventricle. Measurements of acid phosphatase activity provided evidence of no signs of toxicity of isoflurane in the examined areas. The changes in enkephalin levels observed during the isoflurane anesthesia and after its termination depended on the type of examined neuropeptides, as well as on parts of the brain and spinal cord studied. The changes observed after isoflurane administration in enkephalinergic system are discussed with regard to our earlier experiments with halothane and enflurane.     

Chronic 17beta-estradiol augments relaxant role of basal nitric oxide in blood vessels from rats with heart failure

It is estimated that approximately 27% of women have a history of childhood sexual abuse. Long-term effects of this abuse include physical and psychologic consequences that can affect the pregnant woman during the prenatal, antenatal, and postpartum periods. Careful screening of all pregnant women and specific interventions during examinations and procedures can help survivors of childhood sexual abuse experience childbearing as healing and empowering. Care providers who are survivors of such abuse can better serve their patients by working therapeutically on their own healing.     

Two-generation reproduction study of sulfur mustard in rats

Comprehensive data are not available to evaluate the potential risk to reproduction from exposure to sulfur mustard (HD), [bis(2-chloroethyl) sulfide]; thus, the reproductive effects of HD were evaluated in Sprague-Dawley rats. Groups, of rats (27 females and 20 males/group/generation) were gavaged with 0, 0.03, 0.1, or 0.4 mg/kg HD 5 d/week for 13 weeks prior to mating and throughout gestation, parturition, and lactation in a 42-week, 2-generation study. Growth of adult F1 rats of both sexes was reduced by the 0.4 mg/kg exposure. There were no significant effects on reproductive function or pregnancy outcome in either generation, except for an altered sex ratio in the 0.4 mg/kg group. Although not different at birth, growth of the 0.4 mg/kg F1 and F2 offspring was depressed during lactation. A dose-related lesion of the squamous epithelium of the forestomach was observed in adults of both sexes and both the F1 and F2 generation. For a given treatment, the incidence was approximately the same for each sex at each generation. When animals were pooled by sex and generation, approximately 70% (66 out of 94) of the low dose group had only mild microscopic lesions, 72% (68 out of 94) of the intermediate dose group had moderate lesions, and 81% (76 out of 94) of the high group had marked lesions. The lesion, acanthosis, was characterized by thickening of the squamous musoca with varying degrees of hyperkeratosis. Benign neoplasms of the forestomach were found in about 10% of the intermediate and high dose groups in both F0 and F1 generations. Based on these results, the No-Observable-Adverse-Effect-Level (NOAEL) is 0.1 mg/kg/d.     

2-Hydroxy-4-glutathion-S-yl-17beta-estradiol and 2-hydroxy-1-glutathion-S-yl-17beta-estradiol produce oxidative stress and renal toxicity in an animal model of 17beta-estradiol-mediated nephrocarcinogenicity

Measuring the vertical displacement of the center of mass (COM) of the body during walking may provide useful information about the energy required to walk. Four methods of varying complexity to estimate the vertical displacement of the COM were compared in 25 able-bodied, female subjects. The first method, the sacral marker method, utilized an external marker on the sacrum as representative of the COM of the body. The second method, the reconstructed pelvis method, which also utilized a marker over the sacrum, theoretically controlled for pelvic tilt motion. The third method, the segmental analysis method, involved measuring motion of the trunk and limb segments. The fourth method, the forceplate method, involved estimating the COM displacement from ground reaction force measurements. A two-tailed paired t-test within an ANOVA showed no statistically significant difference between the sacral marker and the reconstructed pelvis methods (p = 0.839). There was also no statistically significant difference between the sacral marker and the segmental analysis method (p = 0.119) or between the reconstructed pelvis and the segmental analysis method (p = 0.174). It follows that the first method, which is the most simple, can provide essentially the same estimate of the vertical displacement of the COM as the more complicated second and third measures. The forceplate method produced data with a lower range and a different distribution than the other three methods. There was a statistically significant difference between the forceplate method and the other methods (p < 0.01 for each of the three comparisons). The forceplate method provides information that is statistically significantly different from the results of the kinematic methods. The magnitude of the difference is large enough to be physiologically significant and further studies to define the sources of the differences and the relative validity of the two approaches are warranted.     

The fate of 17 beta-estradiol in the plasma of premenopausal and postmenopausal patients with cancer

The patterns of radioactive estrogen metabolities in the plasma of patients with a variety of malignancies were determined after the injection of physiological amounts of 17 beta-estradiol-6,7-3H or of estrone-6,7-3H. The metabolites were separated and isolated from the plasma by the following procedures: a) alumina chromatography, b) modified Brown procedure, and c) gas liquid chromatography. This study showed that the conjugated state of the estrogens varied with the subjects's age. There was a dramatic decrease in the relative quantity of the plasma free estrogens which are converted to sulfates as the age of the patient increased. This change was noted just prior to menopause, suggesting that there are alterations in the conjugation of plasma estrogens which are detectable before clinical menopause.     

Protective action of 17beta-estradiol in cardiac cells: implications for hyperkalemic cardioplegia

BACKGROUND: Hyperkalemic cardioplegic solutions effectively arrest the heart, but may also induce intracellular Ca2+ loading and cellular hypercontracture, which could contribute to ventricular dysfunction associated with global surgical ischemia. Recently, it has been proposed that 17beta-estradiol may possess protective properties in the ischemic myocardium. The purpose of the present study was to examine the action of 17beta-estradiol on cardiac cells exposed to hyperkalemic stress. METHODS: Single ventricular cardiomyocytes, a preparation devoid of vascular and neuronal elements, were isolated from guinea pig hearts, loaded with a Ca2+-sensitive fluorescent probe, and imaged by digital epifluorescent microscopy. The emitted fluorescence of the probe, a measure of intracellular Ca2+ concentration, and cell length were simultaneously recorded during hyperkalemic challenge, in the absence or presence of 17beta-estradiol. RESULTS: In control cardiomyocytes, the cytosolic concentration of Ca2+ was 138+/-11 nmol/L and cell length 93+/-11 microm. Exposure to high K+ (+16 mmol/L KCl) significantly increased cytosolic Ca2+ to 2,191+/-87 nmol/L (p < 0.001), and produced cell shortening (length at 39+/-5 microm; p < 0.001). 17beta-Estradiol (10 micromol/L) acutely prevented high K+ to induce either intracellular Ca2+ loading (144+/-13 nmol/L, p < 0.001) or hypercontracture (91+/-10 microm, p < 0.001). Tamoxifen (10 micromol/L), an antiestrogen, abolished the protective effect of 17beta-estradiol. CONCLUSIONS: We conclude that 17beta-estradiol prevents hyperkalemia-induced Ca2+ loading and hypercontracture through a direct and tamoxifen-sensitive action in cardiomyocytes. This study raises the possibility that 17beta-estradiol should be considered as a cardioprotective adjunct toward a safer hyperkalemic cardioplegia.     

Comparison between urinary pyridinium cross-links and hydroxylysine glycosides in monitoring the effects of ovariectomy and 17 beta-estradiol replacement in aged rats

This study was undertaken to assess the sensitivity of hydroxylysylpyridinoline (HP), lysylpyridinoline (LP), galactosylhydroxylysine (GHyl) and glucosylgalactosylhydroxylysine (GGHyl) to monitor bone response to estrogen deficiency and replacement by comparing their excretory patterns in ovariectomized aged (11-14 months old) rats. The ovariectomized (OVX) rats were randomized into two groups: (1) OVX plus vehicle; (2) OVX plus 17 beta-estradiol (17-beta E, 10 micrograms/kg, s.c., 4 days/week). Treatment with 17-beta E started immediately after OVX and continued for 60 days. The collagen catabolites were measured in urine for 1 month before OVX and thereafter for 60 days. In temporal coincidence with urine collection, bone area and bone mineral density (BMD) of lumbar vertebrae, femoral diaphysis and distal metaphysis were measured by dual-energy X-ray absorptiometry. In the untreated rats, BMD of the femoral metaphysis and lumbar vertebrae decreased significantly and the urinary excretion of LP, HP, GHyl and GGHyl increased with different patterns. In the treated rats, 17-beta E replacement prevented the increment in LP excretion, partially prevented the increase in HP excretion, but had no effect on the excretion of GHyl and GGHyl. In conclusion pyridinolines and glycosides have different sensitivities to the bone response to OVX. Glycoside excretion after OVX also reflects metabolic processes not strictly related to bone loss and, in contrast with LP, is not sensitive to estrogen replacement.     

Examination of 17 beta-estradiol and progesterone levels in peritoneal fluid and blood serum of women with endometriosis

Authors have presented and assessment of estradiol and progesterone levels in peritoneal fluid and blood serum in women with endometriosis. Peritoneal fluid was collected during laparoscopy performed in luteal phase of the cycle. In this cycle ovulation was controlled in all women. An ovulation was confirmed ultrasonographically and laparoscopically in 45% of women with endometriosis and in 80% of that without the illness. Progesterone concentration in peritoneal fluid in women with endometriosis was significantly lower to the control (p < 0.01).     

Role of gender and vascular endothelium in rat aorta response to 17 beta-estradiol

Estrogen supplementation in postmenopausal women offers significant cardiovascular protection. The mechanism for this benefit is unclear but may be due to an interaction of estrogen with the blood vessel wall (vascular smooth muscle and endothelium). We examined the response of weight-matched female and male endothelium-intact and -denuded aortae to 17 beta-estradiol, its interaction with noradrenaline, and the effect of N-nitro-L-arginine. Estradiol produced relaxation responses that were significantly greater in female endothelium-intact preparations. This response was sensitive to N-nitro-L-arginine, while the response to 17 beta-estradiol in male endothelum-intact and both female and male endothelum-denuded preparations was resistant. Estradiol also inhibited contractions to noradrenaline, which was more pronounced in the female endothelium-intact aortic rings. These data imply that estradiol interacts preferentially with the female vascular endothelium, but there exists an endothelium-independent process that can also be activated in the male aorta. Further studies are warranted to elucidate these differential mechanisms.     

Norethindrone acetate enhances the antiatherogenic effect of 17beta-estradiol: a secondary prevention study of aortic atherosclerosis in ovariectomized cholesterol-fed rabbits

OBJECTIVE: Premature delivery is difficult to predict and causes considerable neonatal morbidity and mortality. Despite much research, little progress has been made in timely identification of the mothers at risk. We examined the uterine cervix with ultrasonography to discover whether such a procedure would be helpful in determining which women will deliver prematurely. METHODS: We performed transvaginal ultrasound examinations in addition to routine transabdominal ultrasonography at 18 to 22 weeks' gestation in 3694 consecutive pregnant women with live singleton fetuses. We measured the length of the uterine cervix and evaluated the dilatation, if any, of the internal os. The results of cervical ultrasonography were not available to the clinicians. RESULTS: Spontaneous delivery occurred before 37 completed weeks in 88 women (2.4%) and before 35 weeks in 31 (0.8%). The relative risk of delivery before 35 weeks was 8 (95% confidence interval 3, 19) when the cervical length was 29 mm or shorter. When dilatation of the internal cervical os of 5 mm or greater was present, the relative risk of delivery before 35 weeks was 28 (95% confidence interval 12, 67). Either short cervix (29 mm or less) or dilatation of internal cervical os (5 mm or greater) was present in 3.6% of the population; this combination had a sensitivity of 29% in predicting delivery at earlier than 35 weeks. After adjusting for cervical dilatation and length by using multiple logistic regression, nulliparity also remained a risk factor for delivery before 35 weeks (odds ratio 3.6, 95% confidence interval 1.7, 7.5). CONCLUSION: Transvaginal ultrasonography performed as an addition to routine transabdominal ultrasonography at 18 to 22 weeks helps to identify many patients at significant risk for prematurity; however, low sensitivity and low positive predictive value limit its usefulness in screening low-risk obstetric populations.     

Subchronic feeding study of four white mineral oils in dogs and rats

Subchronic 90-day feeding studies were conducted on four highly refined white mineral oils to determine any potential for toxicity in Long-Evans rats (20 per sex per dose level) and beagle dogs (4 per sex per dose level). Each oil was fed at dietary dose levels of 300 ppm and 1500 ppm (w/w). No treatment-related effects of toxicological importance were detected in daily observations of general health or in periodic assessments of food consumption and body weight, hematology, serum clinical chemistry, and urinalysis. Observations in dogs suggested that the white oils produced mild laxative effects. Gross and histopathologic examinations, as well as measurements of organ weights, did not reveal any macroscopic or microscopic changes which could be due to treatment. In addition, special staining by Oil Red O of liver, mesenteric lymph nodes, spleen, gastrointestinal tract, stomach, and kidneys indicated no evidence of oil or lipid deposition. A special re-examination of tissues from female and male rats, in response to more recent conflicting data from the Fischer 344 strain, found no histopathologic signs of macrophage accumulation and/or microgranuloma formation in liver, spleen, or mesenteric lymph nodes. These data indicate that repeated exposure to relatively high levels of white mineral oils in the diets does not produce significant subchronic toxicity in Long-Evans rats or beagle dogs.     

Tobacco, alcohol, and drug use in a primary care sample: 90-day prevalence and associated factors

The authors reviewed and presented the criteria used to classify the toxic effects of chemicals such as carcinogenic, irritation, corrosive, allergic, and fetotoxicity, as well as dermal absorption of chemical agents. The criteria for assigning symbols to the Polish list of chemical MAC values has not as yet been determined. Following the analysis it may be concluded that all chemical compounds, which satisfy the requirements should be indexed on the MAC list.     

Predation and feeding: Comparisons of feeding behavior of killer and nonkiller rats.

Studied feeding behavior of 34 killer and 34 nonkiller male Long-Evans rats when (a) hungry, (b) with food available, and (c) with prey and other food of high and low palatability. 3 experiments showed that the act of killing did not potentiate feeding but killers were more responsive to dead prey as food than were nonkillers. Results of this and previous studies suggest that the relationship between attack and feeding is not important to the maintenance of killing. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of combined 17 beta-estradiol and vitamin E on low-density lipoprotein oxidation in postmenopausal women

In conclusion, combined administration of 17beta-estradiol and vitamin E protects LDL in postmenopausal women from oxidation with no synergism noted compared with either therapy given alone.     

In vitro growth of skin fibroblasts of patients with atypical ductal hyperplasia of the breast: effects of 17 beta-estradiol

In this work we investigated the growth of skin fibroblasts, in vitro cultured, drawn from women suffering Atypical Ductal Hyperplasia (I.D.A.) and from healthy women (controls). Whether in basic conditions or after administration of 17, beta-estradiol, in single of repeated dose, cellular growth was valued. The results obtained show that skin fibroblasts drawn from women suffering I.D.A. treated with 100 microliters/ml of estradiol (effective dose), have an increase of the growth. Moreover the increase of the growth seems to be bequest to "effective dose" but not to the number of administrations.     

Oral 17 beta-estradiol continuously combined with dydrogesterone lowers serum lipoprotein(a) concentrations in healthy postmenopausal women

Lipoprotein(a) [Lp(a)] is an independent risk factor for atherosclerosis. Serum Lp(a) concentrations increase after menopause, and postmenopausal estrogen replacement appears to decrease Lp(a) levels. In a randomized, double blind study, we examined the effects of 6-month treatment with daily 17 beta-estradiol (E2; 2 mg, orally) continuously combined with one of four dosages [2.5 mg (n = 41), 5 mg (n = 38), 10 mg (n = 38), and 15 mg (n = 20)] of dydrogesterone on fasting serum Lp(a) concentrations in 137 healthy postmenopausal women. At baseline, no significant differences were noted among the four treatment groups. During the study period of 6 months the median serum Lp(a) concentration decreased significantly from 128 mg/L (range, 5-1660) to 110 mg/L (range, 1-1530) in the total population, corresponding to a reduction of 13% (P < 0.001). The percent changes in serum Lp(a) correlated positively with the percent changes in serum E2 at 3 as well as 6 months of therapy (r = 0.38; P < 0.001 and r = 0.35; P < 0.001, respectively). A dose response of dydrogesterone on serum Lp(a) was not found. In addition, serum lipids and (apo)lipoproteins improved significantly in all four treatment groups. In conclusion, oral E2 continuously combined with dydrogesterone has beneficial effects on the lipid and lipoprotein profile and is effective in lowering Lp(a) concentrations in postmenopausal women.     

Proteins in the heat shock-70 family specifically bind 25-hydroxyvitamin D3 and 17beta-estradiol

Most New World primates evolved to express a form of compensated resistance to steroid hormones from the gonads and adrenal glands as well as to the hydroxylated vitamin D3 prohormone, 25-hydroxyvitamin D3 (25OHD3), and the vitamin D hormone 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] originating from the liver and kidney, respectively. We recently demonstrated that this form of resistance is associated with the overexpression of a novel member of the 70-kDa heat shock protein (hsp-70) molecular chaperone family, which we have termed the intracellular vitamin D binding protein (IDBP). In the current report we more closely examine the ligand-binding capability of purified IDBP and two other mammalian hsp-70 family members, heat-inducible (hsp-70) and constitutively expressed (hsc-70) hsp-70 proteins. Purified IDBP, hsp-70, and hsc-70 all bound 25OHD3 with relatively high affinity; the mean Kd for 25OHD3 ranged from 0.5-2.2 nmol/L (rank order: IDBP > or = hsp-70 > or = hsc-70). By Scatchard analysis, high affinity, specific binding of 1,25-(OH)2D3 was not reproducibly observed for any of the three members of the hsp-70 family. Unlike purified IDBP, hsc-70 and hsp-70 were also competent binders of the gonadal steroid 17beta-estradiol (mean Kd for 25OHD3, 2.5 and 6.6 nmol/L by hsc-70 and hsp-70, respectively), but not of two other gonadal hormones, progesterone and testosterone. These data suggest that IDBP is relatively specific for 25OHD3 and that additional hsp-70-like binding proteins are present in unpurified New World primate cell extracts that are specific for 1-hydroxylated vitamin D metabolites as well as other gonadal steroid hormones.     

Synthesis of 17beta-estradiol by isolated ovarian tissues of the pregnant rat: aromatization in the corpus luteum

Corpora lutea from pregnant rats were incubated to determine their ability to produce 17beta-estradiol and to aromatize testosterone in vitro. Corpora lutea and non-luteal ovarian tissues were removed from rats on days 7, 15, and 22 of pregnancy, and these tissues were immediately frozen or incubated separately in medium 199 at 37 C in an atmosphere of 95% O2-5% CO2 for 4 h. 17Beta-Estradiol in tissue and medium were quantified by a highly specific radioimmunoassay. The estradiol content ivnariably increased in non-luteal tissues during incubation, while it decreased or remained the same in incubated corpora lutea. The synthesis in non-luteal tissues, which was 18 to 400-fold greter. The incubation of corpora lutea (5 to 25 mg of tissue) with testosterone (200 ng) on days 7, 15, and 22 of pregnancy resulted in a mean accumulation of 17beta-estradiol in medium of 2.5 x 103 pg/mg tissue, compared with a mean value of 6 pg/mg for luteal tissue removed from the same ovaries and incubated without testosterone. The incubation of corpora lutea from 15-day pregnant rats with (7alpha-3H)-testosterone resulted in 15% conversion to presumptive (7alpha-3H)17beta-estradiol, which was isolated identically to estradiol isolated for radioimmunoassay. Recrystallization to constant specific activity revealed a high degree of radiochemical purity (75%) of the isolated (3H)estradiol. Rat diaphragm muscle and rabbit corpora lutea did not aromatize testosterone to 17beta-estradiol in amounts detectable by radioirpora lutea in vitro is virtually diol by non-luteal ovarian tissues. However,the corpora lutea show a striking capacity to aromatize testosterone, which might explain the high estradiol content of the rat corpora lutea during pregnancy. The physiological significance of this aromatizing system and of 17beta-estradiol in the corpus luteum is unknown but may be related to the luteotropic action of estradiol in the pregnant rat.     

The effect of 17 beta-estradiol and endothelin 1 on prostacyclin and thromboxane production in human endothelial cell cultures

The authors present an account on a neonate with dextro-lateral renal venous thrombosis. They focus attention on the diagnostic and therapeutic procedure and compare it with available data from the literature. Contrary to data in the literature, they did not observe in the acute stage of renal venous thrombosis signs of disseminated intravascular coagulation in peripheral blood. It did not prove possible to elucidate the action of any of the factors leading to the development of renal venous thrombosis. After evidence of permanent functional loss of the right kidney nephrectomy was performed. Histopathological examination provided evidence of obliterating thrombosis of the renal veins with partial recanalization and calcifications. The authors emphasize the necessity of early diagnosis of renal venous thrombosis and adequate treatment based on the revealed findings.