PI3K, AKT, and P-AKT levels in thin endometrium.

The aim of this study was to explore the expression of PI3K, AKT, and P-AKT, and to investigate the role of PI3K/AKT signaling pathway in thin endometrium. We included 40 women treated in affiliated Shenzhen Nanshan People's Hospital of Guangdong Medical University for endometrial conditions between August 2013 and January 2015, 20 with a normal endometrium, and 20 with thin endometrium. The expression of PI3K, AKT, and P-AKT was evaluated by the immunohistochemical S-P method. The expression of PI3K, AKT, and P-AKT proteins was significantly lower in the thin endometrium group than in the normal endometrium group (P < 0.05). The expression of PI3K and AKT was positively correlated with the expression of P-AKT. The expression of PI3K, AKT, and P-AKT proteins in the thin endometrium decreases during the proliferative phase, and this process could be associated with PI3K/AKT signaling.

Female sexual function and dysfunction in the reproductive years: the influence of endogenous and exogenous sex hormones.

INTRODUCTION: Sexual function in women in the reproductive age years is under psychological, sociocultural, and relationship influences, as well as the influence of sex hormones. AIM: To examine the data relating to sexual function in women in the reproductive age group, particularly the influence of sex hormones. To examine, in particular, the influence of the menstrual cycle, pregnancy, the oral contraceptive pill and endogenous and exogenous testosterone. METHODS: Review of the literature on female sexual function, confining the search to the reproductive age range. RESULTS: Population studies of sexual function identify sexual disinterest as being the most common sexual complaint in premenopausal women. Most studies of menstrual cyclicity identify a periovulatory increase in sexual desire or activity. All prospective studies of sexuality in pregnancy document a decline in sexual function with progression of pregnancy. Studies of the influence of the oral contraceptive pill on sexual function are contradictory with most prospective controlled studies showing no deleterious effect. Studies of the influence of endogenous androgens on sexuality are also contradictory with one large cross-sectional study showing no correlation, but some case-controlled studies show low androgens in women with sexual dysfunction. Studies of testosterone therapy in premenopausal women are ambiguous, with no clear dose-response effect. CONCLUSIONS: Sexual disinterest is prevalent in premenopausal woman despite being hormone replete. The assessment of androgen contribution is hampered by the unreliability of the testosterone assay in the female range. Large cross-sectional and longitudinal studies have not identified a correlation between testosterone and sexual function in women. Sexual dysfunction in the premenopausal age range is common. Sex hormones have a modifying effect on sexual function but social influences and learned responses are as important. The role of testosterone requires further study.

Stable isotope-coded quaternization for comparative quantification of estrogen metabolites by high-performance liquid chromatography-electrospray ionization mass spectrometry.

A fast and sensitive LC-ESI-MS method is described for the comparative quantification of 16 estrogen metabolites based on the derivatization of estrogens with a novel derivatizing reagent, N-methyl-nicotinic acid N-hydroxysuccinimide ester (C1-NA-NHS). The process introduces a quaternary amine to the analytes, making the analytes permanently charged regardless of the pH of the high-performance liquid chromatography (HPLC) mobile phase. This quaternization resulted in a highly efficient separation of 16 estrogen metabolites in 7 min at a detection level below 1 ng/mL. By using a deuterated derivatizing reagent (C1-d(3)-NA-NHS), a complete set of deuterated standards was utilized and used as internal standards in a comparative quantification and recovery study, demonstrating acceptable results over a wide concentration range. A pooled breast cancer serum sample was analyzed using the described method, and 15 estrogens were detected in the range of 80-530 pg/mL.

Analysis of estrogens and androgens in postmenopausal serum and plasma by liquid chromatography-mass spectrometry.

Liquid chromatography-selected reaction monitoring/mass spectrometry-based methodology has evolved to the point where accurate analyses of trace levels of estrogens and androgens in postmenopausal serum and plasma can be accomplished with high precision and accuracy. A suite of derivatization procedures has been developed, which together with modern mass spectrometry instrumentation provide investigators with robust and sensitive methodology. Pre-ionized derivatives are proving to be useful as they are not subject to suppression of the electrospray signal. Postmenopausal women with elevated plasma or serum estrogens are thought to be at increased risk for breast and endometrial cancer. Therefore, significant advances in risk assessment should be possible now that reliable methodology is available. It is also possible to conduct analyses of multiple estrogens in plasma or serum. Laboratories that are currently employing liquid chromatography/mass spectrometry methodology can now readily implement this strategy. This will help conserve important plasma and serum samples available in Biobanks, as it will be possible to conduct high sensitivity analyses using low initial sample volumes. Reported levels of both conjugated and non-conjugated estrogen metabolites are close to the limits of sensitivity of many assays to date, urging caution in the interpretation of these low values. The analysis of serum androgen precursors in postmenopausal women has not been conducted routinely in the past using liquid chromatography/mass spectrometry methodology. Integration of serum androgen levels into the panel of metabolites analyzed could provide additional information for assessing cancer risk and should be included in the future.

Estrogens and Their Genotoxic Metabolites Are Increased in Obese Prepubertal Girls.

CONTEXT: Estrogen levels and their metabolites are higher in obese vs lean postmenopausal women, and obesity increases breast cancer risk. Quinone derivatives of 4-hydroxylated estrogen metabolites, independently of the estrogen receptor, cause depurination and impaired DNA repair (genotoxic). 16α-Hydroxy (16α-OH)-estrone (E1), eg, promotes tumor proliferation and 2-methoxy-estradiol (E2) may be chemoprotective. Childhood obesity increases breast cancer death risk in women, but levels of estrogen derivatives had not been previously studied in young children. OBJECTIVE: The objective of the study was to investigate whether total and genotoxic estrogens are increased in prepubertal obese girls compared with lean controls. DESIGN: Stored sera from 12 lean and 23 obese prepubertal girls (Tanner stage I breast and pubic hair) studied previously were assayed for E1, E2, and their multiple metabolites (12 steroids total) using highly sensitive liquid chromatography and tandem mass spectrometry. RESULTS: E2 concentrations were significantly higher in obese [3.45 (0.5, 4.65) pg/ml (median [quartile 1, quartile 3])] vs lean girls [0.5 (0.5, 2.37), P = .04], 57% of values upper quartile or greater (quartile 3) of controls. Concentrations of 16α-OH-E1 were higher in obese [7.17 (0.5, 9.64) pg/mL] vs lean girls [0.5 (0.5, 1.72, P = .007)], 65% of values quartile 3 or greater of controls. 2-Methoxy-E2 concentrations were lower in the obese group (P = .012). 16α-OH-E1 concentrations were positively correlated with body mass index, percentage fat mass, and IL-6 concentrations (P < .001). CONCLUSIONS: E2 and genotoxic metabolites were higher in obese vs lean prepubertal girls. These data suggest that obesity is associated with an increased extraglandular estrogen production and metabolism before the onset of puberty in girls. Long-term epidemiological studies are needed to assess any potential increase in breast cancer risk.

Effect of an oral contraceptive on the plasma levels of budesonide and prednisolone and the influence on plasma cortisol.

OBJECTIVE: To investigate whether the use of an oral contraceptive would influence plasma levels of budesonide (Entocort capsules) or prednisolone (plain tablets) during repeated oral administration of these glucocorticosteroids. Plasma concentrations of cortisol and ethinyl estradiol (INN, ethinylestradiol) were also compared. METHODS: Forty healthy women took part in this single-blind, randomized placebo-controlled study with two parallel groups, where a three-way crossover design was applied within groups. One group was taking an oral contraceptive (150 microg desogestrel and 30 microg ethinyl estradiol); the other group (control) was not. On seven consecutive mornings, oral doses of 4.5 mg budesonide, 20 mg prednisolone, or placebo were administered. There was a washout period of at least one menstrual cycle between administration periods. RESULTS: In the oral contraceptive users, the average plasma concentration of prednisolone was 131% higher than in the control group (P < .001), whereas the average plasma concentration of budesonide was only 22% higher (not significant). Mean plasma cortisol levels were suppressed by 90% and 82% with prednisolone and by 22% and 28% with budesonide in oral contraceptive users and the control subjects, respectively. The group difference was significant with prednisolone (P < .001) but not with budesonide. Ethinyl estradiol levels in plasma were not affected by administration of either glucocorticosteroid. CONCLUSION: No difference was found in plasma levels of budesonide or in cortisol suppression after administration of budesonide capsules in women taking the oral contraceptive and those who were not. The oral contraceptive users had much higher plasma levels of prednisolone and greater cortisol suppression. This result suggests that oral budesonide can be used with maintained safety in women using oral contraceptives.

Thalidomide does not alter the pharmacokinetics of ethinyl estradiol and norethindrone.

OBJECTIVE: To evaluate the effect of thalidomide on the plasma pharmacokinetics of ethinyl estradiol (INN, ethinylestradiol) and norethindrone (INN, norethisterone). METHODS: Ten women who had undergone surgical sterilization were enrolled in an open-label crossover study conducted in the Georgetown University Clinical Research Center. The pharmacokinetics of single doses of 0.07 mg ethinyl estradiol and 2 mg norethindrone were measured at baseline and after 3 weeks of 200 mg thalidomide. Compliance with the thalidomide regimen was assessed with use of Medication Event Monitoring System (MEMS) caps. RESULTS: No changes were observed in the pharmacokinetics of ethinyl estradiol or norethindrone with thalidomide therapy. The mean +/- SD area under the plasma concentration-time curve (AUC0-infinity) for ethinyl estradiol was 6580 +/- 1100 ng.h/L at baseline and 5970 +/- 1560 ng.h/L after the thalidomide regimen (paired t test, P > .05). The values for norethindrone were 103 +/- 54 micrograms.h/L and 107 +/- 58 micrograms.h/L (paired t test, P > .05). No changes were observed for other pharmacokinetic parameters assessed for either ethinyl estradiol or norethindrone. No accumulation of thalidomide was seen after 21 days of therapy: day 1 AUC0-infinity 41.1 +/- 13.9 micrograms.h/mL; day 21 AUC0-infinity 59.6 +/- 27.3 micrograms.h/mL (paired t test, P > .05). No changes were observed for other pharmacokinetic parameters assessed for thalidomide between days 1 and 21. Thalidomide was well tolerated but caused variable degrees of sedation. The average thalidomide compliance rate was 97%. CONCLUSIONS: The pharmacokinetics of thalidomide do not change with 3 weeks of daily dosing. Thalidomide does not alter the pharmacokinetics of ethinyl estradiol or norethindrone. Therefore there is no drug interaction between thalidomide and these 2 drugs. The efficacy of oral contraceptives containing ethinyl estradiol and norethindrone should not be affected by concomitant thalidomide therapy.

PIP: An open-label crossover study was conducted to evaluate the effect of thalidomide on the plasma pharmacokinetics of ethinyl estradiol (INN, ethinyl estradiol) and norethindrone (INN, norethisterone) among 10 women who had undergone surgical sterilization at Georgetown University Clinical Research Center. The pharmacokinetics of single doses of 0.07 mg ethinyl estradiol and 2 mg norethindrone were measured at baseline and after 3 weeks of 200 mg thalidomide. Compliance with the thalidomide regimen was assessed with the use of Medication Event Monitoring System caps. The results showed that there were no changes in the pharmacokinetics of ethinyl estradiol or norethindrone with thalidomide therapy. Furthermore, no changes were seen for other pharmacokinetic parameters assessed for thalidomide between days 1 and 21. Thalidomide was well tolerated, but caused variable degrees of sedation. The average compliance rate of thalidomide was 97%. This study concluded that there was no drug interaction between thalidomide and the other two drugs (ethinyl estradiol and norethindrone). The efficacy of oral contraceptives containing ethinyl estradiol and norethindrone should not be affected by concomitant thalidomide therapy.

Effects of felbamate on the pharmacokinetics of a low-dose combination oral contraceptive.

The effects of felbamate on the pharmacokinetics of a low-dose combination oral contraceptive containing 30 micrograms ethinyl estradiol and 75 micrograms gestodene were assessed in a randomized, double-blind, placebo-controlled parallel-group study in healthy premenopausal female volunteers established in a regimen of oral contraceptive use. They received either placebo or 2400 mg/day felbamate from midcycle (day 15) to midcycle (day 14) of two consecutive oral contraceptive cycles (months 1 and 2). Pharmacokinetic assessments of ethinyl estradiol and gestodene were performed on day 14 of both cycles. To determine whether ovulation occurred, plasma progesterone and urinary luteinizing hormone levels were measured, and diaries recording vaginal bleeding were kept. Felbamate treatment resulted in a significant 42% decrease in gestodene area under the plasma concentration-time curve (0 to 24 hours) (p = 0.018) compared with baseline, whereas a minor but not clinically relevant effect was observed on the pharmacokinetic parameters of ethinyl estradiol. There were no changes in the pharmacokinetics of ethinyl estradiol or gestodene after placebo treatment. No volunteer showed hormonal evidence of ovulation; however, one volunteer reported the onset of intermenstrual bleeding during felbamate treatment. Because of the effect of felbamate on the pharmacokinetics of gestodene and the report of intermenstrual bleeding, it is possible that the contraceptive efficacy of low-dose combination oral contraceptives may be adversely affected during felbamate treatment.

Interactions between oral contraceptives and antifungals/antibacterials. Is contraceptive failure the result?

The effectiveness of oral contraceptives may be impaired by concomitant treatment with antimicrobials. This may occur because of reductions in plasma concentrations of ethinylestradiol by the induction of hepatic metabolism, as for rifampicin (rifampin) and possibly griseofulvin, or in a small percentage of women because of interference with enterohepatic recirculation. There are no scientific data to support the anecdotal evidence that the concomitant use of combined oral contraceptives and antimicrobials reduces contraceptive efficacy in the majority of women. It has been postulated that there is a subset of women in whom the enterohepatic recirculation of ethinylestradiol plays an important role. In these women the action of an antimicrobial may reduce the efficacy of oral contraceptives by interfering with this mechanism. Studies that have quantitatively examined these effects may have failed to include women from this subset because of the small numbers involved in the studies. On the other hand, there are no good prospective studies comparing contraceptive failure rates between compliant women who use combined oral contraceptives with and without antimicrobials. All women using combined oral contraceptives should be informed of the very low level of risk of interactions with antimicrobials (probably about 1%) and that it is not possible to identify who may be at risk. Women concerned about this low level of risk should be given information about the use of barrier methods or avoidance of intercourse during the first 7 days of concomitant antimicrobial therapy and for 7 subsequent days. Women who have had previous contraceptive failures or developed breakthrough bleeding during concomitant antimicrobial use should be strongly advised to follow these precautions, as they may be part of the subset of women at higher risk of contraceptive failure.

Pharmacokinetics of norelgestromin and ethinyl estradiol from two consecutive contraceptive patches.

The primary objective of this open-label study was to determine the pharmacokinetics of norelgestromin (NGMN) and ethinyl estradiol (EE)following two consecutive applications of a contraceptive patch (ORTHO EVRA/EVRA). Twelve healthy women wore the first patch on their abdomen for 7 days and, after removal at 168 hours (day 7), wore a second patch for 10 days (i.e., 3 days beyond the intended 7-day wear period). Blood samples were collected before and at various times up to 456 hours (day 19) after application of the first patch for analysis of NGMN and EE. Mean serum concentrations of NGMN and EE remained within the reference ranges, 0.6 to 1.2 ng/ml and 25 to 75 pg/ml, respectively, during the entire 7-day wear period after application of the first patch and for 10 days after application of the second patch; reference ranges are based on studies with ORTHO-CYCLEN/ Cilest. No patch detached spontaneously. No subject discontinued or experienced a serious adverse event.

Evaluation of single- and multiple-dose pharmacokinetics of synthetic conjugated estrogens, A (Cenestin) tablets: a slow-release estrogen replacement product.

A multiple-dose, placebo-controlled, randomized pharmacokinetic study was performed in 15 early (i.e., 1-3 years) postmenopausal women to evaluate the single and steady-state pharmacokinetics of 0.625 mg Cenestin (Synthetic Conjugated Estrogens, A) tablets, administered once daily for 90 days. Plasma concentration-time profiles for both total (conjugated and unconjugated) estrone and equilin, two major estrogens in Cenestin, were nearly superimposable between Day 1 (single dose) and Day 90 (multiple dose), indicating equivalent drug exposure from one dose to the next. For total estrone, the mean estimates of Cmax and AUC0-24 were 2.5 ng/ml and 35.0 ng x h/ml for Day 1 and 3.0 ng/ml and 39.8 ng x h/ml for Day 90, respectively. Similarly, Cmax and AUC0-24 mean values for total equilin were 1.4 ng/ml and 17.4 ng x h/ml after Day 1 and 1.5 ng/ml and 17.3 ng x h/ml after Day 90, respectively. The mean tmax value for total estrone was 8.3 hours on Day 1 and 8.6 hours on Day 90, indicating a slower rate of absorption. The average estimate for observed drug accumulation index for the 24-hour dosing interval was calculated to be 1.1 for total estrone and 1.0 for total equilin. These data, taken together, indicate a slow and steady rate of absorption, minimal drug accumulation at steady state, and consistent drug exposure between Cenestin doses.

Medical castration using megestrol acetate and minidose estrogen.

Sixty-two men who presented with previously untreated metastatic carcinoma of the prostate (D0: 10 patients; D1: 29 patients; D2: 23 patients) received oral megestrol acetate (80 mg twice daily) and minidose estrogen (diethylstibestrol 0.1 mg or ethinyl estradiol 0.05 mg once daily) as a means of achieving total androgen ablation (testicular and adrenal). A high incidence of feminizing side effects (70-74%), a higher than expected rate of cardiovascular complications (18%), an unexpected need for cortisone replacement (13%), and failure of patients with Stage D2 disease to obtain results better than those of standard therapy during the first year of observation suggest this regimen offers no advantage over other more conventional therapy.

Study of the pharmacokinetic interaction between ethinylestradiol and amoxicillin in rabbits.

Several antibiotics have been implicated in oral contraception failure when they are administered at the same time as the oral contraceptive (OC) pill. In the present paper, a study about amoxicillin-ethinylestradiol (EE2) pharmacokinetic potential interaction was studied. Two rabbit groups were utilized, the first group received amoxicillin (10 mg/kg) and EE2 (30, 50 and 100 micrograms/kg, respectively), both by intravenous (i.v.) route. The second group received amoxicillin (oral route, 10 mg/kg/day) and EE2 (i.v. route, 100 mu/kg) on day 1, 4 and 8 of antibiotic treatment, respectively. After compartmental (two-compartment open model) and non-compartmental analysis of plasma concentrations, the statistical study (ANOVA p < or = 0.05) revealed that the presence of amoxicillin did not modify the EE2 distribution and elimination pharmacokinetic parameters (by comparison with those obtained in a previous study where EE2 was administered alone). There also were no significant differences with the time of amoxicillin oral treatment.

In vivo conversion of norethisterone and norethisterone acetate to ethinyl etradiol in postmenopausal women.

Previous studies with postmenopausal women receiving oral doses of norethisterone-containing preparations have shown that a small fraction of the dose is converted metabolically to ethinyl estradiol and may be detected in the peripheral blood. To investigate the extent and the dose dependence of this conversion in more detail, we performed a study with 24 postmenopausal women who received single oral doses of 5 mg norethisterone as well as 5 and 10 mg norethisterone acetate with a washout phase of 2 weeks between each treatment. After each treatment, blood was collected at regular intervals and the concentrations of norethisterone and ethinyl estradiol were analyzed in the serum samples by a specific radioimmunoassay and by gas chromatography/mass spectrometry, respectively. Ethinyl estradiol was present in the serum samples of all women following treatment with norethisterone acetate and, except for four cases, also after treatment with norethisterone. The conversion ratio of norethisterone acetate to ethinyl estradiol was 0.7 +/- 0.2% and 1.0 +/- 0.4% at doses of 5 and 10 mg, respectively. This corresponded to an oral dose equivalent of about 6 micrograms ethinyl estradiol per milligram of norethisterone acetate. For norethisterone, a conversion ratio of 0.4 +/- 0.4% was found at a dose of 5 mg, which corresponded to an oral dose equivalent of about 4 micrograms ethinyl estradiol per milligram of norethisterone. Although it cannot be excluded that in individual cases, even higher doses of ethinyl estradiol may be produced by conversion, it is concluded that at therapeutic doses of the progestogens, the exposure to metabolically derived ethinyl estradiol is probably of little clinical significance not only in fertile women using oral contraceptive combination preparations containing norethisterone and ethinyl estradiol, but also in postmenopausal women who receive oral doses of estradiol for estrogen replacement. The estrogenic effects of metabolically derived ethinyl estradiol on the liver (eg. synthesis of transport proteins) are very likely more than compensated due to the androgenic activity of norethisterone.

Can grapefruit juice influence ethinylestradiol bioavailability?

The effects of grapefruit juice on the bioavailability of 17 alpha-ethinylestradiol (EE2) after a single oral administration of 50 micrograms EE2 have been investigated. The pharmacokinetics of EE2 were studied in an open, randomized, cross-over study in which 13 healthy volunteers were administered the drug with herbal tea or grapefruit juice (naringin, 887 mg/ml). In contrast to herbal tea, grapefruit juice increased the peak plasma concentration (Cmax) significantly to 137% (mean; range 64% to 214%, p = 0.0088) and increased the area under plasma concentration-time curve from 0 to 8 hours (AUC0-8) to 128% (mean; range 81% to 180%, p = 0.0186). This study shows that grapefruit juice increases the bioavailable amount of EE2. A possible explanation may be that grapefruit juice inhibits the metabolic degradation of EE2. Whether the increased bioavailability of EE2 following grapefruit juice administration is of clinical importance should be investigated in long-term studies.

Effect of oral contraceptives containing 20 and 35 micrograms ethinyl estradiol on urinary prostacyclin and thromboxane metabolite levels in smokers and nonsmokers.

The interaction between smoking and oral contraceptive (OC) use with respect to thrombogenesis was investigated by studying the effects of OC and smoking on urinary prostacyclin (PGI2) and thromboxane A2 (TxA2) metabolite levels in smokers and nonsmokers. Sixty healthy women, aged 19-32 years, who were not taking any hormonal treatment for at least 3 months before initiating the study, were divided into three equal groups: OC users who smoked (N = 20), OC users who did not smoke (N = 20), and a control group of 10 smokers and 10 nonsmokers. Each OC treatment group was randomized to receive either norethindrone (NET) acetate (1 mg)/ethinyl estradiol (EE2) (35 micrograms) (N = 10) or NET acetate (1 mg)/EE2 (20 micrograms) (N = 10) daily for 3 months. Overnight urine collections and fasting blood samples were obtained at baseline and at the end of the 3-month study. Serum levels of NET and EE2, as well as urinary levels of cotinine and the stable metabolites of PGI2 and TxA2, namely 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) and thromboxane (TxB2), respectively, were measured by specific immunoassays. Analysis of pre- to posttreatment changes in mean urinary 6-keto-PGF1 alpha and TxB2 levels for each subgroup, as determined by smoking status and EE2 dose, showed no statistically significant differences. Also, no significant differences were found in each subgroup with respect to changes in the 6-keto-PGF1 alpha/TxB2 ratios. Large intersubject variability in urinary 6-keto-PGF1 alpha and TxB2 levels were observed in all subgroups. The results of this study indicate that both low-estrogen-dose compounds, when used by smokers or nonsmokers, did not significantly alter the ratio of PGI2 to TXA2 metabolites, compared with pretreatment. However, the small number of subjects and the large intersubject variability in this study make it difficult to determine if there is a significant difference between the 20- and 30-microgram EE2 doses.

Comparative pharmacokinetics of two new steroidal estrogens and ethinylestradiol in postmenopausal women.

It was the aim of the study to compare the pharmacokinetic properties of the two new estrogens, ZK 136295 and ZK 115194, with those of ethinylestradiol (EE2) after single intravenous (60 micrograms) and oral (120 and 240 micrograms) administration in 54 postmenopausal women. In particular, our objective was to examine whether one or both compounds were characterized by an improved oral bioavailability with less inter-subject variability than EE2. Drug serum concentrations were determined using specific radioimmunoassays for EE2 and ZK 136295, and a GC/MS/MS-method for ZK 115194. Following i.v. administration of the new estrogens and of EE2, the drugs were rapidly distributed in the body. The mean terminal half-lives were calculated to be 12.3 +/- 12.4, 28.7 +/- 9.6, and 26.1 +/- 11.1 h for ZK 136295, ZK 115194, and EE2 respectively. After oral administration of 120 micrograms, the absolute bioavailability was calculated to be about 40% for ZK 136295 as well as for EE2 with a high inter-individual variation (variation coefficient: 44 and 67%). By doubling the dose, the systemic availability increased dose-dependently for both drugs to about 70% with the same high inter-individual variation. Following single oral administration of 240 micrograms ZK 115194, the absolute bioavailability amounted to 33 +/- 19%. The present study clearly revealed that although the two new estrogens differed considerably in their pharmacokinetic behavior, they demonstrated a reduced and highly variable systemic availability similar to that of EE2.

PIP: Researchers with the pharmaceutical manufacturer Schering AG in Berlin, Germany, conducted a double-blind clinical trial in 54 healthy, postmenopausal women to compare the pharmokinetic properties of two new estrogens (ZK 136295 and ZK 115194) with those of ethinyl estradiol (EE2). Specifically, they examined whether one or both of the new estrogens improved bioavailability with less inter-subject variability than EE2. The dosage included single intravenous (60 mcg) and oral (120 and 240 mcg) administration. ZK 115195 differs from natural estradiol by 14alpha, 17alpha-bridging, which should prevent early metabolic degradation during absorption and passage through the liver. ZK 136295 is the corresponding derivative of endogenous estriol. All three compounds were rapidly distributed throughout the body. ZK 136295 had the shortest mean terminal half-life; ZK 115194 had the longest (12.3 vs. 28.7 hours); and EE2 had a mean terminal half-life of 26.1 hours. Oral administration of 120 mcg effected an absolute bioavailability of about 40% for ZK 136295 and EE2. The inter-individual variation was high (variation coefficient = 44% and 67%) for both compounds. When the oral dose was 240 mcg, systemic availability increased dose-dependently for ZK 136295 and EE2 to around 70% with the same high inter-individual variation. Oral administration of 240 mcg of ZK 115194 effected an absolute bioavailability of about 33%. These findings show that the 14alpha, 17alpha-bridging of estradiol does not result in a higher bioavailability than that achieved by introduction of a 17alpha-ethinyl group. Yet, increasing the dose of ZK 115194 and of EE2 from 120 to 240 mcg increased their absolute bioavailability two-fold. In conclusion, even though the pharmacokinetic behavior of the two new estrogens differed markedly, the two estrogens exhibited a reduced and highly variable systemic availability similar to that of EE2.

Interaction of estrogen mimics, singly and in combination, with plasma sex steroid-binding proteins in rainbow trout (Oncorhynchus mykiss).

The plasma sex steroid-binding protein (SBP) is believed to be involved in regulating circulating endogenous sex steroids as well as cellular signal transduction to nuclear steroid receptors in sex steroid-sensitive tissues. In this study, a variety of estrogen mimics (EMs), which may contribute to the endocrine disrupting effects observed in fish, were tested for the ability to interact with the rainbow trout plasma sex steroid-binding protein (rtSBP) either singly or in binary combinations. The EMs ethynylestradiol, diethylstilbestrol, 4-hydroxytamoxifen, genistein, zearalenone, 4-t-octylphenol, bisphenol A and o,p'-DDT were all able to displace 1,2,4,6,7-[3H]estradiol from the sex steroid-binding site at the rtSBP (K(d)=2.1+/-0.5 nM, B(max)=2963+/-303 fmol estradiol/mg protein) in a dose-dependent and competitive manner. The plastizicer n-butyl benzyl phthalate only displayed weak binding affinity for the rtSBP, whereas the pesticide dieldrin was not able to compete for the high affinity estradiol-binding sites in plasma. None of the compounds tested was able to clearly promote the binding of the others when given in combination, indicating that synergy did not occur at the ligand-SBP binding level. The rtSBP binding affinity for EMs ranged over several orders of magnitude, but were consistently lower than those for the endogenous sex steroids (about 10(2)-10(6) less potent). The results suggest that the presence of rtSBP may potentially modulate the bioavailability of EMs to estrogen receptors relative to each other and to the endogenous sex steroids themselves. Since the binding of the endogenous ligands is reversible, SBP-bound estrogens (or androgens) potentially may also become displaced by potent EMs.

Sequential radioimmunoassay of unconjugated and conjugated estrogen in male human plasma.

A sequential radioimmunoassay procedure for unconjugated and conjugated estrone, estradiol-17 beta and estriol in male human plasma was developed. The blank values in this assay for unconjugated estrone, estradiol-17 beta, estriol conjugated estrone, estradiol-17 beta and conjugated estriol were 0.36 +/- 1.14 pg, 3.90 +/- 2.75 pg, 2.25 +/- 2.08 pg, 0.92 +/- 1.51 pg, 5.02 +/- 2.86 pg and 3.12 +/- 2.97 pg, respectively. Mean values of unconjugated estrone, estradiol-17 beta, estriol, conjugated estrone, estradiol-17 beta and conjugated estriol in plasma from 28 normal adult males were 38.4 +/- 13.4 pg/ml, 32.6 +/- 9.90 pg/ml, 4.06 +/- 3.68 pg/ml, 34.2 +/- 13.8 pg/ml, 40.4 +/- 12.3 pg/ml and 31.8 +/- 7.41 pg/ml, respectively. Both unconjugated and conjugated estrogen levels in patients with liver cirrhosis were elevated and conjugated estrogen, especially estriol levels, in patients with renal insufficiency were markedly elevated.

[Evaluation of the hormonal replace therapy (HRT) effect on generation of reactive oxygen intermediates (ROI) by neutrophil in peripheral blood of menopausal women]. / Ocena wplywu hormonalnej terapii zastepczej u kobiet w okresie menopauzalnym na zdolnosc generacji reaktywnych form tlenu przez neutrofile krwi obwodowej.

UNLABELLED: About 30% of women population in Poland is already in the perimenopausal age. HRT (hormonal replacement therapy) is the best way of diminishing the unfavorable symptoms of this state. AIM OF STUDY: The effect of HRT on ROI production by neutrophils before and after HRT, to determinate it's antioxidative influence on cells. MATERIAL: We have examined 40 women both from the Dept. of Menopausal Disease in the Research Institute Polish Mother's Memorial Hospital (RIPMMH) and Out Patient Menopausal Clinic of RIPMMH with average age of 49.8; between October 1997 and January 1998. METHODS: We determined ROI generation by luminol-enhanced chemiluminescence, using standard stimuli like fLMP, PMA and OZ. We used Luminometer 1251, manufactured by Pharmacia-LKB. For statistic evaluation Fisher test, Kolmogorow-Smirnow test and T-student test were used. RESULTS: We found that estrogen-progestagen therapy had a suppressive effect on generation of ROI by neutrophils in vitro and in vivo after using receptor dependent and non-dependent stimuli. ROI generation by neutrophils of peripheral blood induced by PMA, a receptor dependent stimuli, is diminished, both, after HRT or as an effect of estrogen-progestagen action in vitro. The results suggest direct inhibition effect on the neutrophil ability to ROI generation.