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Lack of difference among progestins on the anti-atherogenic effect of ethinyl estradiol: a rabbit study.

BACKGROUND: Progestins in combination with estrogen are believed to have different effects on the cardiovascular system. The aim of this study was to investigate the influence of different oral contraceptive formulations on the development of experimental atherosclerosis and vascular reactivity. METHODS: A total of 160 sexually mature rabbits were ovariectomized and randomly assigned to equally large groups: (i) a cholesterol-rich diet (320 mg/day), either given alone (placebo), or together with (ii) ethinyl estradiol (EE 70 micro g/day, oral), (iii) desogestrel (DSG 525 micro g/day, oral), (iv) gestodene (GSD 262.5 micro g/day, oral), (v) levonorgestrel (LNG 525 micro g/day, oral), (vi) EE + DSG, (vii) EE + LNG, or (viii) EE + GSD. After 31 weeks of treatment, aortic accumulation of cholesterol and vascular vasoreactivity (in vitro) were determined. RESULTS: Progestins alone did not reduce the accumulation of cholesterol. EE alone or in combination with a progestin reduced the accumulation of cholesterol relative to placebo (P < 0.0001). Isolated vessels from EE-treated animals relaxed significantly more to physiological concentrations of acetylcholine than did placebo (P < 0.001), whereas vessels treated with EE plus a progestin showed an intermediate response. CONCLUSION: The progestins investigated can be combined with EE without attenuating the anti-atherogenic effect of EE.

Animals↗

Catabolism of HDL1 cholesteryl ester in the rat. Effect of ethinyl estradiol treatment.

The present study was performed in control and ethinyl estradiol-treated rats in order to determine the mechanisms involved in the catabolism of HDL1 cholesteryl ester. Ligand blottings on liver membranes showed that purified HDL1, containing about 70% apolipoprotein E and 10% apolipoprotein AI, bind to the LDL receptor (130 kDa) and not to HB2 (100 kDa) or SR-BI (82 kDa), candidate HDL receptors. Immunoblots showed that the treatment increased the hepatic level of the LDL receptor five- to ten-fold, strongly decreased that of SRBI and did not change that of HB2. An in vivo kinetic study showed that the turnover of HDL1 cholesteryl ester is more rapid in treated than control rats. The liver participation (60%) in this clearance was not modified by the treatment. Therefore, it can be concluded that the catabolism of HDL1 cholesteryl ester, in control as in treated rats, is essentially ensured by the uptake of entire particles in the hepatocytes via LDL receptors.

Adrenal Glands↗

Effect of ethinyl estradiol treatment on lipoproteins and LCAT activity in aged rats.

The induction of hepatic lipoprotein (apo B/E) have been investigated in Fischer-344 rats. These studies were aimed to determine the mechanism underlying the previously observed (Lee et al., Mech. Ageing Dev., 61 (1991) 85-98) hypercholesterolemia and the age-related decrease in the fractional rate of endogenous cholesterol esterification. Young (5 months) and aged (22 months) male Fischer-344 rats were treated with pharmacological doses (5 mg/kg per day) of ethinyl estradiol (EE) for 7 days. Reduction of plasma cholesterol (57% in young vs 47% in aged rats) and high density lipoprotein cholesterol (64% in young vs 63% in aged rats) occurred in both groups upon EE treatment. Initial low density lipoprotein levels were very low in the plasma of young rats and consequently were not affected by EE treatment. However, in aged rats, the low density lipoprotein levels were much higher initially and were markedly reduced by EE treatment. (18.0 vs 10.0 mg/dl). Very low density lipoproteins were about the same initially but increased in aged rats and decreased in young rats upon EE treatment. Both the lecithin:cholesterol acyltransferase (LCAT) activity (as determined with a proteoliposome substrate) and the fractional rate (FR) of the endogenous cholesterol esterification decreased in treated animals compared to controls. However, the differences in the FR of the endogenous cholesterol esterification between young and aged rats (observed before treatment) were nearly abolished upon treatment. These data suggest that the previously observed age related decrease in the FR of endogenous cholesterol esterification is due to the accumulation of apolipoprotein E-rich (apo E) lipoproteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

Lack of prepubertal administration of ethinyl estradiol on susceptibility to multiple organ carcinogenesis in rats exposed to 7,12-dimethylbenz[a]anthracene and N-bis(2-hydroxypropyl)nitrosamine during adolescence.

Estrogen exposure during the adult period is widely known to promote tumor development in the female genital system, as well as in the mammary gland in experimental animals, but its carcinogenic potential with exposure at the prepubertal stage, for 6 weeks after birth, is not completely understood. In the present study, we therefore evaluated the modifying effects of prepubertal ethinyl estradiol (EE) treatment on susceptibility to multiple organ carcinogenesis with subsequent carcinogen exposure in F344 rats. Dams during the lactation period and their weaned offspring until postnatal-week 6 were fed diet containing 0, 0.2 or 1.0 ppm EE. The offsprings were then administered 7,12-dimethylbenz[a]anthracene (DMBA, 50mg/kg body weight) by gavage for mammary tumor induction in week 7 and given free access to drinking water containing N-bis (2-hydroxypropyl)nitrosamine (DHPN, 0.2%) for wide spectrum tumor induction in organs such as the thyroid, liver, lung and kidney from weeks 6-14. Male and female offspring were euthanized at weeks 27 and 36, respectively, for histopathological examination. While the incidence and multiplicity of mammary tumors showed a tendency for increase in females of the 0.2 and 1.0 ppm EE groups, this was without statistical significance. Furthermore, prepubertal EE exposure did not affect tumor induction in the thyroid, liver, lung, kidney, esophagus, ovary and lymphoid tissue in either sex. The present results thus indicate a lack of influence of estrogen early in life on carcinogenic susceptibility, although the possible impact on mammary carcinogenesis requires further examination.

9,10-Dimethyl-1,2-benzanthracene↗

Escitalopram versus ethinyl estradiol and norethindrone acetate for symptomatic peri- and postmenopausal women: impact on depression, vasomotor symptoms, sleep, and quality of life.

OBJECTIVE: To examine the efficacy and tolerability of escitalopram (ESCIT) compared to estrogen and progestogen therapy (EPT) for the treatment of symptomatic peri- and postmenopausal women. DESIGN: Forty women (aged 40-60 years) with depressive disorders and menopause-related symptoms were randomly assigned to an 8-week open trial with ESCIT (flexible dose, 10-20 mg/day; fixed dose, 10 mg/day for the first 4 weeks) or estrogen plus progestogen therapy (ethinyl estradiol 5 microg/day plus norethindrone acetate 1 mg/day). Primary outcome measures included Montgomery-Asberg Depression Rating Scale and the Greene Climacteric Scale at week 8. Secondary outcome measures included the Clinical Global Impressions as well as sleep and quality of life assessments. RESULTS: Thirty-two women (16 on EPT, 16 on ESCIT) were included in the analyses. Full remission of depression (score of <10 on the Montgomery-Asberg Depression Rating Scale) was observed in 75% (12/16) of subjects treated with ESCIT, compared to 25% (4/16) treated with EPT (P = 0.01, Fisher's exact tests). Remission of menopause-related symptoms (>50% decrease in Greene Climacteric Scale scores) was noted in 56% (9/16) of women treated with ESCIT compared to 31.2% (5/16) on EPT (P = 0.03, Pearson's chi2 tests). Improvement in sleep, hot flashes, and quality of life was observed with both treatments. CONCLUSIONS: ESCIT is more efficacious than EPT for the treatment of depression and has a positive impact on other menopause-related symptoms. ESCIT may constitute a treatment option for symptomatic menopausal women who are unable or unwilling to use hormone therapy.

Adult↗

ICMR Task Force Study on hormonal contraception. Biological activity of ethinyl estradiol present in the breast milk.

A study was conducted to compare the biological activity of the estrogenic component of the endogenous steroids in breast milk samples collected during various phases of lactation with those milk samples collected from women who were on estrogen therapy. The estrogenic biological activity in the milk sample was assessed by the immature mouse uterine weight gain assay. Milk samples collected during postpartum period from six different study groups, viz., control colostrum of 1-3 days and 4-6 days, transitional milk (10-20 days) and mature milk (1-3 months) were compared with colostrum and mature milk of women treated with Lynoral (ethinyl estradiol 0.1 mg) three times a day for three days. Estrogenic activity was observed only in animals injected with milk extracts of colostrum samples from both control and Lynoral-treated women; however, they were not significantly different from each other. Therefore it is not the exogenous estrogens, but the endogenous estrogen present in large quantities in the colostrum that is responsible for the biological activity.

Animals↗

Effects of prolonged administration of the 19-nor-testosterone derivatives norethindrone and norgestrel to female NZB/W mice: comparison with medroxyprogesterone and ethinyl estradiol.

To evaluate effects of commonly used progestational estrogenic contraceptive steroids in a hormone-responsive model of lupus, we treated female NZB/W mice before clinical disease (6 wks of age) and after onset of lupus (24 wks of age) with doses of hormones titered to suppress reproduction. We report efficacy of norethindrone (NE) and norgestrel (NG), progestins derived from 19-nor-testosterone, in delaying expression of anti-DNA antibodies. Mice implanted with NG at 24 wks of age had prolonged lifespans. In contrast, the hydroxyprogesterone derivative, medroxyprogesterone acetate (MP), did not affect autoimmune disease. These observations suggest that prolonged administration of 19-nor-testosterone derivatives, in small doses adequate to suppress reproduction, may have ameliorative effects in systemic lupus erythematosus. Mice receiving ethinyl estradiol (EE) plus courses of tetracycline to suppress cystitis had active anti-DNA responses. In 60% of EE-treated mice, however, early deaths resulted from malignant lymphomas and complications of obstructive uropathy. Estrogen toxicity, rather than accelerated lupus, was the major cause of death in NZB/W mice treated with EE.

Animals↗

Effects of low-dose norethindrone acetate plus ethinyl estradiol (0.5 mg/2.5 microg) in women with postmenopausal symptoms: updated analysis of three randomized, controlled trials.

BACKGROUND: Based on the potential risks of post-menopausal hormone therapy (HT) found by the Women's Health Initiative, guidelines for HT now recommend use of the lowest effective dose and shortest treatment duration consistent with individual treatment goals. Current (2003) guidance established by the US Food and Drug Administration (FDA) recommends that clinical assessments of HT include women with more frequent and more intense vasomotor symptoms than previously studied. Therefore, this analysis was conducted to further assess the efficacy of a low-dose combination of norethindrone acetate and ethinyl estradiol (NA/EE) previously assessed in dose-ranging studies, while meeting conservative FDA trial design and analysis criteria. OBJECTIVES: The aim of this post hoc analysis and overview was to present data on the efficacy and tolerability of a low-dose combination-NA/EE 0.5 mg/2.5 microg-in the treatment of postmenopausal symptoms, based on data from previously published studies of NA/EE. In addition, the effects of low-dose NA/EE on bone and endometrium are briefly reviewed. METHODS: Data from 3 previously published randomized, placebo-controlled trials were analyzed using current FDA guidance for the assessment of HT in postmenopausal women. Studies 1 and 2 assessed the efficacy of NA/EE at various doses, including 0.5 mg/2.5 microg, in vasomotor symptom (hot-flush [HF]) relief over 16 and 12 weeks, respectively, using self-reporting of symptom frequency and intensity (scores: 0=none; 1=mild; 2=moderate; and 3=severe) in daily diaries. Study 3 assessed the effects of NA/EE at various doses, including 0.5 mg/2.5 microg, on bone and endometrium, using quantitative computed tomography of the lumbar spine at 12 and 24 months and endometrial biopsy at 6, 12, 18, and 24 months of treatment. In all 3 studies, women were asked to record vaginal bleeding and spotting in diaries. Any adverse events were recorded in diaries and/or at clinic visits. Physical and gynecologic examinations and standard clinical laboratory testing were conducted at baseline and at appropriate follow-up visits in all 3 studies. RESULTS: Studies 1, 2, and 3 enrolled 219, 266, and 1265 women, respectively. Overall, in studies 1 and 2, 91% of women were white, the mean age was approximately 52 years, and mean time since last menstrual period was approximately 24 months. In study 1, NA/EE 0.5 mg/2.5 microg was associated with significant reductions from baseline in mean weekly total HF frequency from week 4 (63.6%) through week 16 (73.7%) (all, P<0.05). In study 2, the frequency of moderate or severe HFs was decreased by 61.1% at week 4 (P<0.05) and by 82.2% at week 12 (P<0.001) with NA/EE 0.5 mg/2.5 microg, and the mean intensity score was significantly lower than that with placebo at weeks 8 and 12 (both, P=0.001). In study 3, cumulative amenorrhea rates were approximately 90% in the NA/EE 0.5-mg/2.5-microg and placebo groups at 12 months. Lumbar spine bone mineral density (BMD) was maintained at 24 months with NA/EE 0.5 mg/2.5 microg but was significantly decreased from baseline, by 7.4%, in the placebo group (P<0.001). Endometrial hyperplasia was not observed in the group receiving NA/EE 0.5 mg/2.5 microg over 24 months. The tolerability of NA/EE was similar to that of placebo. The most common adverse events experienced with NA/EE were headache (15.2%), abdominal pain (10.2%), and breast pain (9.0%). CONCLUSIONS: The results from this post hoc analysis and overview of 3 previously published studies suggest that NA/EE 0.5 mg/2.5 microg was associated with decreased frequency and intensity of vasomotor symptoms. This dose of NA/EE was also associated with maintenance of BMD over 24 months, a significant positive effect on BMD compared with placebo. Low-dose NA/EE was also associated with cumulative amenorrhea rates comparable to those of placebo and was not associated with endometrial hyperplasia. This dose was well tolerated, with rates of adverse events generally similar to those of placebo.

Bone Density↗

Ethinyl estradiol acutely attenuates abnormal coronary vasomotor responses to acetylcholine in postmenopausal women.

BACKGROUND: Estrogen administration in postmenopausal women is associated with a 50% reduction in the clinical manifestations of coronary artery disease. The mechanisms are not known, although one potential explanation is estrogen-induced modulation of coronary vasoreactivity. Acetylcholine is an endothelium-dependent vasodilator that may be used to assess coronary vasoreactivity and elicits coronary responses that parallel those found with common daily vasomotor stimuli. Therefore, we tested whether estrogen attenuates abnormal coronary vasomotor responses to acetylcholine in postmenopausal women. METHODS AND RESULTS: Acetylcholine-induced changes in coronary flow, resistance, and cross-sectional area were determined before and 15 minutes after intravenous administration of ethinyl estradiol (EE, 35 micrograms) in 15 postmenopausal women. The influence of estrogen on basal coronary flow, resistance, and epicardial cross-sectional area was also assessed by measuring these parameters before and after EE or placebo administration in 33 women. Estrogen altered basal coronary vasomotor tone in 22 women as manifested by an EE-induced 23.3 +/- 4.5% (mean +/- SEM) increase (P < .01) in coronary flow, a 15.0 +/- 3.2% decrease (P < .01) in resistance, and a 20.0 +/- 6.5% increase (P = .02) in epicardial cross-sectional area. Placebo administration in 11 women did not change these parameters. Estrogen also attenuated abnormal coronary vasomotor responses to acetylcholine. Seven women who exhibited a paradoxical acetylcholine-induced decrease in coronary flow (-33.5 +/- 12.3%, P < .01) and increase in resistance (38.9 +/- 14.1%, P = .05) and seven who had an abnormal acetylcholine-induced decrease in epicardial cross-sectional area (-14.2 +/- 4.4%; P = .04) did not have acetylcholine-induced changes in these parameters after EE administration. Acetylcholine-induced flow, resistance, and cross-sectional area responses before and after EE were significantly different (P < .01, P = .02, and P = .02, respectively). Normal coronary responses to acetylcholine were not affected by EE administration. CONCLUSIONS: EE attenuates abnormal coronary vasomotor responses to acetylcholine in postmenopausal women. EE also decreases basal coronary vasomotor tone as manifested by increased coronary flow, decreased resistance, and increased epicardial cross-sectional area. These acute effects of estrogen on coronary vasoreactivity may explain, in part, the cardioprotective effects of estrogen in postmenopausal women.

Acetylcholine↗

Comparison of serum ethinyl estradiol, sex-hormone-binding globulin, corticoid-binding globulin and cortisol levels in women using two low-dose combined oral contraceptives.

The study included 69 women taking a desogestrel (n = 30)- or gestodene (n = 39)-containing low-dose combined oral contraceptive for at least 3 months. Group size was calculated to detect a difference in mean values of 80% of 1 standard deviation (alpha = 0.05, beta = 0.1). Seven serum samples were obtained up to 4 h, and 1 sample 24 h, after drug intake on 1 day between the 10th and the 21st day of the cycle. The concentrations of sex-hormone-binding globulin (SHBG), corticoid-binding globulin (CBG) and cortisol were measured in a 0- to 4-hour serum pool by radioimmunoassay. Ethinyl estradiol (EE2) levels were analyzed in single and pooled samples using anti-EE2-6 beta-carboxymethyloxime-bovine serum albumin antiserum. The area under the curves (AUC) up to 4 and 24 h and Cmax and tmax were evaluated. Statistical analysis (analysis of covariance) did not reveal a dependence of values on duration of treatment or day of cycle. Both treatments resulted in almost identical values for all parameters evaluated. The mean levels of SHBG, CBG and cortisol were in the range of 186-226 nmol/l, 89-93 mg/l and 280-281 micrograms/l, respectively. Mean maximum EE2 levels of 106-129 pg/ml were found 1.6-1.8 h after pill intake and AUC0-4 h accounted for 329-374 pg.h.ml-1. The recently reported differences in serum EE2 and CBG levels between two groups of 11 women each treated with desogestrel- and gestodene-containing pills, respectively, could not be confirmed.

Adult↗

Effect of ethinyl estradiol on the panic response to the panicogenic agent pentagastrin.

BACKGROUND: Panic disorder (PD) symptomatology has been reported to be altered by hormonal events or treatments which affect estrogen levels. Coryell et al. [Arch. Gen. Psychiatry, 39 (1982) 701-703; Am. J. Psychiatry, 143 (1986) 508-510] have suggested that the increased cardiovascular risk associated with PD is significantly greater in males, alluding to a potential cardioprotective effect of female hormones in the context of panic attacks. In the present study, we were, therefore, interested in elucidating the role of estrogen in modulating the behavioural and cardiovascular responses induced by the panicogenic agent pentagastrin, a cholecystokinin-B (CCK(B)) receptor agonist. METHODS: A double-blind cross-over placebo-controlled design with randomization of the order of a 3-day pretreatment of ethinyl estradiol (EE) (50 microg/day) or placebo was used to assess the effect of a 30-microg i.v. bolus injection of pentagastrin on panic symptom intensity and on increases in heart rate (DeltaHR), systolic (DeltaSBP) and diastolic (DeltaDBP) blood pressure following each pretreatment. Subjects were 9 male healthy controls and 11 male PD patients. RESULTS: EE pretreatment did not significantly reduce the pentagastrin-induced panic symptom scale (PSS) scores and had no effect on DeltaDBP or DeltaSBP. EE did, however, attenuate the pentagastrin-induced increase in HR in both PD patients and healthy controls. LIMITATIONS: Only male subjects were included in the present study; however, we are currently investigating the influence of female gonadal hormones on the panic response to pentagastrin in female PD patients and healthy controls. CONCLUSION: Our results suggest that estrogens may display cardioprotective effects in the context of panic attacks.

Adult↗

Effects of low-density lipoprotein and ethinyl estradiol on cyclosporine metabolism in isolated rat liver perfusions.

The effects of low-density lipoprotein (LDL) on cyclosporine (CyA) metabolism were studied in the isolated perfused rat liver, in a recirculating mode, using Krebs-Ringer buffer in the absence (control perfusion) or presence of LDL (1 microM) (LDL perfusion). In the LDL perfusions, CyA concentrations at all sampling times were about 2-fold higher, whereas the biliary excretion of CyA and measured metabolites (AM1, AM9, AM1c, and AM4N) were all lower than those obtained with the control perfusions. At the end of the perfusion (3 hr), the percentage of total CyA remaining (liver, bile, and perfusate) was significantly higher (76 +/- 1.2% to 85 +/- 2.4%) and the percentage of dose metabolized to AM9 was lower (4.8 +/- 1.2% to 2.4 +/- 0.6%) in the LDL perfusions (N = 4). These results further suggest the inhibitory effects of LDL on CyA uptake, and, thereby, its metabolism as we observed previously in isolated rat hepatocyte studies. Because ethinyl estradiol (EE) is known to increase LDL receptors in rats, we investigated the possible involvement of LDL receptors in transporting CyA into liver cells using rats pretreated with EE (5 mg/kg/day sc for 5 days). The effects of LDL in maintaining CyA perfusate concentrations, and in decreasing biliary excretion of CyA and its metabolites in the EE-treated animals, were in the same direction as those noted in animals without EE, but the differences due to LDL were not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Tenoxicam versus lynestrenol-ethinyl estradiol treatment of dysfunctional uterine bleeding cases during adolescence.

BACKGROUND: The purpose of this study was to compare the effectiveness of tenoxicam versus lynestrenol-ethinyl estradiol (L-EE) in the treatment of severe cases of dysfunctional uterine bleeding (DUB) during adolescence. METHODS: Forty-eight patients with objective DUB completed a randomized comparative trial of treatment with tenoxicam (20 mg daily, n = 23) or L-EE (1 tablet containing 0.05 mg + 2.5 mg, respectively, 3 times daily, n = 25). Treatment was given during menorrhagia until bleeding ceased. Mean age of the patients was 13.74 +/- 2.1 years (range, 11-18 years). RESULTS: A significantly higher level of hematocrit (35.9% v 32.6%, t = 2.1, P = 0.0217) and hemoglobin (11.5 v 10.4 g%, t = 1.7, P = 0.0495), and significantly less hospitalization (5.75 v 8.33 days, t = 2.45, P = 0.0106) was seen in the tenoxicam group in comparison to L-EE group after completion of the treatment. Three patients were submitted to curettage and seven to transfusion in the group receiving L-EE, but no patients in the tenoxicam group required these procedures. CONCLUSIONS: Tenoxicam is considered an effective medication for the management of DUB during adolescence.

Adolescent↗

Long-term 17alpha-ethinyl estradiol treatment decreases cyclin E and cdk2 expression, reduces cdk2 kinase activity and inhibits S phase entry in regenerating rat liver.

BACKGROUND/AIMS: The synthetic estrogen 17alpha-ethinyl estradiol (EE), a potent tumor promoter in rat liver, stimulates growth during short-term treatment but inhibits hepatocyte proliferation upon prolonged treatment. To identify the molecular targets of the mitoinhibitory effect of EE, the expression of proteins regulating G(1)- and S-progression were analyzed during the first cell cycle in EE-treated female Wistar rats. METHODS: Long-term (60 days) EE treatment. Immunohistochemical staining for proliferation cell nuclear antigen (PCNA) to detect cells in S phase and quantification of mitosis. Western blot to monitor protein expression. Cdk2 kinase assay to examine histone H1 phosphorylation. RESULTS: EE reduced the number of cells in S phase and mitosis by about 70%. Cyclin D1 and D3 were unaffected, while cdk4 was moderately decreased. Cyclin E and cdk2 were markedly decreased with concomitant marked reduction of cdk2 kinase activity. EE also decreased cyclin A and increased G1 levels of p53 and p21. CONCLUSIONS: EE causes a cell cycle block before S-phase. The reduction of the cdk2 kinase activity, essential for G1/S-transition, might be involved in the cell cycle block. Also, EE treatment results in p53 activation and upregulation of the cdk inhibitor p21 that might contribute to the G1 arrest.

Animals↗

Sinusoidal endothelial endocytosis of low density lipoprotein-gold conjugates in perfused livers of ethinyl-estradiol treated rats.

We examined endocytosis of low-density lipoproteins (LDL) conjugated to colloidal gold by the sinusoidal endothelium in perfused livers of 17 alpha-ethinyl estradiol-treated rats. After 15 min of perfusion, the gold-LDL was randomly bound at the endothelial surface, but internalized only at coated pits. Uptake of the conjugate was to electron-lucid vacuoles. After 1 h of perfusion, there was a progressive accumulation of gold in organelles resembling lysosomes, with further accumulation seen at 2 h perfusion. Uptake of the conjugate was equivalent to the rate of 125I-LDL and competitively inhibited by a 20-fold excess of free LDL. These results suggest that a specific endocytotic pathway for LDL is present in the sinusoidal endothelium in the estrogen-hypolipidemic state.

Animals↗