Comparative metabolism of 17alpha-ethynyl steroids used in oral contraceptives

Solid-phase synthesis of libraries of ethynylated aminosteroid derivatives as potential antileukemic agents

Steroids possessing an ethynyl group at position 17α (tertiary alcohols) are well known to be more stable than their non-ethynyl analogs (secondary alcohols). To facilitate the development of new drugs with better metabolic stability, we developed a new diethylsilyl acetylenic linker allowing us to rapidly synthesize libraries of ethynylated steroid derivatives using a solid-phase strategy. To illustrate its usefulness, this linker was used to expand the molecular diversity of a lead compound having a hydroxy acetylenic pattern and to potentially find new compounds with interesting cytotoxic activity against leukemia cell lines. Herein, we report the chemical synthesis and the characterization of three libraries of ethynylated aminosteroid derivatives using the diethylacetylenic linker. We discuss their antiproliferative activities obtained in 2 leukemia cell lines (HL-60 and Jurkat), which results provided new structure-activity relationships. We also identified a new promising aminosteroid derivative with an azetidine moiety (compound B1) inhibiting 60% and 75% of HL-60 and Jurkat cell proliferation, respectively, at 1 μM. More generally, these results validate the use of a diethylsilyl acetylenic linker for researchers interested in generating libraries of alcohol derivatives with better stability and drug profile.

Occurrence and fate of steroid estrogens in the largest wastewater treatment plant in Beijing, China

Concern over steroid estrogens has increased rapidly in recent years due to their adverse health effects. Effluent discharge from wastewater treatment plants (WWTPs) is the main pollutant source for environmental water. To understand the pollutant level and fate of steroid estrogens in WWTPs, the occurrence of estrone (E1), 17-β-estradiol (E2), estriol (E3), and 17-β-ethinylestradiol (EE2) was investigated in the Gaobeidian WWTP in Beijing, China. Water samples from influent as well as effluent from second sedimentation tanks and advanced treatment processes were taken monthly during 2006 to 2007. In influent, steroid estrogen concentrations varied from 11.6 to 1.1 × 10(2) ng/l, 3.7 to 1.4 × 10(2) ng/l, no detection (nd) to 7.6×10(2) ng/l and nd to 3.3 × 10(2) ng/l for E1, E2, E3, and EE2, respectively. Compared with documented values, the higher steroid estrogen concentrations in the WWTP influent may be due to higher population density, higher birthrate, less dilution, and different sampling time. Results revealed that a municipal WWTP with an activated sludge system incorporating anaerobic, anoxic, and aerobic processes could eliminate natural and synthetic estrogens effectively. The mean elimination efficiencies were 83.2%, 96.4%, 98.8%, and 93.0% for E1, E2, E3, and EE2, respectively. The major removal mechanism for natural estrogens and synthetic estrogen EE2 were biodegradation and sorption on the basis of mass balance in water, suspension particles, and sludge. In the WWTP effluent, however, the highest concentrations of E1, E2, E3, and EE2 attained were 74.2, 3.9, 5.1, and 4.6 ng/l, respectively. This is concerning as residual steroid estrogens in WWTP effluent could lead to pollution of the receiving water. Advanced flocculation treatment was applied in the WWTP and transformed the residual estrogen conjugates to free species, which were reduced further by filtration with removal shifting from 32% to 57% for natural estrogen, although no EE2 was removed.

Occurrences of six steroid estrogens from different effluents in Beijing, China

Concentration levels of six natural and anthropogenic origin steroid estrogens, namely, diethylstilbestrol (DES), estrone (E1), estradiol (E2), estriol (E3), ethinylestradiol (EE2), and estradiol-17-valerate (Ev), from different effluents in Beijing were assessed. Sampling sites include two wastewater treatment plants (WWTPs), a chemical plant, a hospital, a pharmaceutical factory, a hennery, and a fish pool. In general, concentrations of estrogens in the effluents varied from no detection (nd) to 11.1 ng/l, 0.7 to 1.2 × 10(3) ng/l, nd to 67.4 ng/l, nd to 4.1 × 10(3) ng/l, nd to 1.2 × 10(3) ng/l, and nd to 11.2 ng/l for DES, E1, E2, EE2, E3, and Ev, respectively. The concentration levels of steroid estrogens from different effluents decreased in the order of pharmaceutical factory and WWTP inlets > hospital > hennery > chemical factory > fish pool. This study indicated that natural estrogens E1, E2, and E3 and synthetic estrogen EE2 are the dominant steroid estrogens found in the different Beijing effluents. For source identification, an indicator (hE = E3/(E1 + E2 + E3)) was used to trace human estrogen excretion. Accordingly, hE in effluents from the hospital and WWTP inlets exceeded 0.4, while much smaller values were obtained for the other effluents. Human excretions were the major contributor of natural estrogens in municipal wastewater. Estimation results demonstrated that direct discharge was the major contributor of steroid estrogen pollution in receiving waters.

Molecular cloning of vitellogenin gene and mRNA expression by 17alpha-ethinylestradiol from slender bitterling

Indigenous aquatic population such as fish could be used as a successful test species for evaluating the ecological effects in aquatic environment. In the present study, vitellogenin (Vtg) from slender bitterling (Acheilognathus yamatsutae), an indigenous aquatic species in Korea, was cloned and sequenced to determine if the Vtg gene possesses an important characteristic so as to act as a sensitive biomarker for estrogenic endocrine disrupting chemicals (EEDCs). The sbVtg cDNA is 5010 bp in length, containing a 4653 bp open reading frame, which encodes 1550 amino acid residues. The sbVtg cDNA was divided into lipovitellin heavy chain (LvH), phosvitin (Pv), lipovitellin light chain (LvL) as well as a beta'-component (beta'-c) domain, and belongs to VtgAo2. SbVtg has conserved important sequences for Vtg functions such as signal peptide, VtgR-binding region, and disulfide bond formation, all of which are consistent with those of other teleosts. In addition, the male slender bitterling aqueous exposed to 17 alpha-ethinylestradiol (EE2, 12.5, 25, and 50 ng/L) produced a statistically significant and concentration-dependent increase in hepatic Vtg mRNA expression, which showed a similar pattern to biliary estrogenic activity, measured by ERE-reporter gene assay. Thus, this study clearly indicates that the induction of Vtg in slender bitterling might be a suitable biomarker in toxicological research of EEDCs.

Effect of laropiprant, a PGD2 receptor 1 antagonist, on estradiol and norgestimate pharmacokinetics after oral contraceptive administration in women

Laropiprant is a prostaglandin D2 receptor 1 antagonist that is being developed in combination with niacin for the treatment of dyslipidemia. This randomized clinical study evaluated the effect of laropiprant on the pharmacokinetics of ethinyl estradiol (EE) and norelgestromin (NGMN), the principal circulating metabolite of norgestimate, in healthy women receiving 3 or more months of an oral contraceptive (Ortho Tri-Cyclen; Ortho-McNeil Pharmaceutical, Raritan, NJ), which contains EE and norgestimate. Twenty-one female subjects with normal menstrual cycles received the oral contraceptive on Days 1 to 21 during two consecutive contraceptive cycles. Subjects received double-blind 40 mg/day laropiprant or placebo on Days 1 to 21 of each contraceptive cycle. Plasma samples were collected predose and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, and 24 hours postdose on Day 21 to measure area under the plasma concentration-time curve from 0 to 24 hours (AUC0-24hr) and maximum concentration observed in plasma (Cmax) of EE and NGMN. Comparability would be declared if the 90% confidence intervals for the geometric mean ratio of AUC0-24hr and Cmax in the absence and presence of laropiprant were within predefined bounds (0.80-1.25). The estimated geometric mean ratios (90% confidence intervals) of EE and NGMN, respectively, were 1.08 (1.04-1.13) and 0.97 (0.94-0.99) for AUC0-24hr and 1.16 (1.06-1.27) and 1.00 (0.94-1.06) for Cmax. The 90% confidence intervals for the geometric mean ratio of EE Cmax minimally exceeded the prespecified bounds; the other relevant pharmacokinetic parameters fell within the predefined bounds. Coadministration of 40 mg laropiprant with the oral contraceptive did not lead to clinically meaningful alterations in the pharmacokinetics of EE or NGMN.

Fate of conjugated natural and synthetic steroid estrogens in crude sewage and activated sludge batch studies

Steroids are excreted from the human body in the conjugated form but are present in sewage influent and effluent as the free steroid, the major source of estrogenic activity observed in water courses. The fate of sulfate and glucuronide conjugated steroid estrogens was investigated in batch studies using activated sludge grown on synthetic sewage in a laboratory-scale Husmann simulation and crude sewage from the field. A clear distinction between the fate of sulfate and glucuronide conjugates was observed in both matrices, with sulfated conjugates proving more recalcitrant and glucuronide deconjugation preferential in crude sewage. For each conjugate, the free steroid was observed in the biotic samples. The degree of free steroid formation was dependent on the conjugate moiety, favoring the glucuronide. Subsequent degradation of the free steroid (and sorption to the activated sludge solid phase) was evaluated. Deconjugation followed the first order reaction rate with rate constants for 17alpha-ethinylestradiol 3-glucuronide, estriol l6alpha-glucuronide, and estrone 3-glucuronide determined as 0.32, 0.24, and 0.35 h respectively. The activated sludge solid retention time over the range of 3-9 days had 74 to 94% of sulfate conjugates remaining after 8 h. In contrast, a correlation between increasing temperature and decreasing 17alpha-ethinylestradiol 3-glucuronide concentrations in the activated sludge observed no conjugate present in the AS following 8 h at 22 degrees C Based on these batch studies and literature excretion profiles, a hypothesis is presented on which steroids and what form (glucuronide, sulfate, or free) will likely enter the sewage treatment plant.

An orally bioavailable synthetic analog of an active dehydroepiandrosterone metabolite reduces established disease in rodent models of rheumatoid arthritis

Dehydroepiandrosterone (DHEA) treatment provides diverse anti-inflammatory benefits in rodent models of diseases, including rheumatoid arthritis (RA), but only limited benefits to patients. In rodents, DHEA is metabolized to (among others) androstene-3beta,7beta,17beta-triol (AET), which retains potent anti-inflammatory activity. 17Alpha-ethynyl-5-androstene-3beta,7beta,17beta-triol (HE3286) is a novel, metabolically stabilized, orally bioavailable derivative of AET. In the DBA mouse model of collagen-induced arthritis (CIA), once-daily oral treatments (gavage) with HE3286 (40 mg/kg), beginning at onset of disease, significantly decreased disease. Benefit was associated with reduction in joint inflammation, erosion, and synovial proliferation as measured by histological analysis and mRNA of proinflammatory cytokines, including tumor necrosis factor-alpha, interleukin (IL)-6, IL-1beta, and IL-23. Significant benefit was also observed in the CIA model even when treatments were delayed until 7 days after the onset of arthritis. Furthermore, dose-dependent benefit was observed in the DBA mouse model of collagen antibody-induced arthritis, as well as reductions in IL-6 and matrix metalloproteinase-3 mRNA levels in joints at the peak of disease and at the end of the study. HE3286, in contrast to dexamethasone, was not immune-suppressive in several classic animal models of immune function. Instead, HE3286 treatment was associated with reduced nuclear factor-kappaB activation and in our previous studies, with increased regulatory T cells. We hypothesize that HE3286 may represent a novel, perhaps first-in-class, anti-inflammatory agent and may more fully translate the benefits of DHEA, heretofore largely limited to rodents, into treatments for human diseases, including autoimmune disorders such as RA.

Factors controlling the biodegradation of 17beta-estradiol, estrone and 17alpha-ethinylestradiol in different natural soils

We conducted a series of laboratory microcosm incubations with [(14)C]-labeled 17beta-estradiol (E2), estrone (E1) and 17alpha-ethinylestradiol (EE2) in 17 different natural soils to characterize hormone mineralization. A significantly higher mineralization was observed for E1 (2.0-37.6%) and E2 (4.2-50.2%) than for EE2 (0.5-2.6%) in all test soils after 21 days. Soil physical or chemical parameters were not related to estrogen mineralization. Although sorption parameters varied greatly for E2 (K(F)=21.9-317.5 mL g(-1)), for E1 (K(F)=46.0-517.5 mL g(-1)) and for EE2 (K(F)=29.9-326.1 mL g(-1)) this apparently did not control estrogen bioavailability since it showed no effects on hormone mineralization. In order to elucidate the controlling factors, experiments with combined additions of radiolabeled estrogens and different substrates were conducted. Additions of ammonium nitrate or alanine to soil samples generally increased EE2 mineralization, thus indicating N-limitation. Additions of glucose induced higher E2 and EE2 degradation in comparison to control samples which is attributed to co-metabolism. Additions of saw dust, catechol or streptomycin influenced the microbial population in the test soils and affected the mineralization of E2 and EE2. Thus, we clearly demonstrate that different microbial communities are responsible for E2 and EE2 degradation in soils. We suggest that EE2 is mineralized by white-rot fungi and E2 by bacteria.

Formation of estrogenic brominated ethinylestradiol in drinking water: implications for aquatic toxicity testing

17alpha-Ethinylestradiol (EE2) is a synthetic estrogen which is thought to contribute the feminisation of fish exposed to wastewater effluents. During laboratory exposure studies of fish to EE2, it was observed that the estrogen in the aquarium water was rapidly transformed (within 10 min) to mono- and di-brominated A-ring products. Exposure of roach (Rutilis rutilus) to 30 ng L(-1) EE2 resulted in accumulation of dibrominated EE2 in ovaries (apparent bioconcentration factor, BCF 130) and liver (apparent BCF 7894) at concentrations which were 18-67-fold greater than the test EE2 compound. The estrogenic activities of brominated EE2 compounds were tested in an in vitro yeast recombinant estrogen receptor transcription screen (YES). All the brominated products of EE2 were estrogenic, however monobrominated isomers of EE2 were 18-105-fold less estrogenic, and dibrominated EE2 2058-fold less active in the YES than EE2 itself. This study reveals the importance of using chemical methods to verify exposure concentrations of waterborne test chemicals and suggests that bromination of estrogens may occur during water treatment, potentially resulting in the formation of bioavailable estrogenic environmental contaminants.

Effects of intranasal 17β-estradiol administration on serum bioactive interleukin-6 and C-reactive protein levels in healthy postmenopausal women

OBJECTIVE

Oral estrogen increases the levels of C-reactive protein (CRP), which is an independent risk factor for coronary heart disease in healthy individuals. The aim of our study was to investigate the effects of intranasal 17beta-estradiol (E2) on serum CRP and its most potent stimulant, interleukin-6 in healthy postmenopausal women.

DESIGN

Thirty-six healthy postmenopausal women (45-54 y) were enrolled. According to their individual preferences, they were assigned to intranasal (n = 10), transdermal (n = 14), or oral (n = 12) continuous E2 treatment with a sequential progestin (10-14 d in a 28-d cycle). Blood samples were drawn at baseline and after 3, 6, and 12 months during the estrogen-only phase to adjust for the progestin effect.

RESULTS

In women taking intranasal or transdermal E2, there were no significant changes in median serum CRP levels during the 12-month treatment period. In women taking oral E2 preparations, serum median CRP levels were significantly higher compared to baseline after 6 and 12 months of the therapy (P < 0.05). Conversely, serum median bioactive interleukin-6 levels were significantly lower after 6 and 12 months in women taking E2 intranasally or orally and after 12 months in women taking E2 transdermally (P < 0.05).

CONCLUSIONS

The results of our study show that intranasal, similarly to transdermal, E2 administration does not increase serum CRP levels in postmenopausal women. They also support the hypothesis that CRP increase during oral estrogen treatment is not mediated by the enhancement of interleukin-6 production by the immune cells but is rather caused by the hepatic first-pass metabolism effect.

Alteration of steroid hormone profile in juvenile turbot (Psetta maxima) as a consequence of short-term exposure to 17alpha-ethynylestradiol

The synthetic estrogen 17alpha-ethynylestradiol (EE2) is among the most potent xenoestrogens found in treated sewage. Adverse effects have been reported in fish exposed to this chemical, such as vitellogenin induction or alteration of gonad structure. In this study, the effects of EE2 on sex steroid profile in juvenile turbot (Psetta maxima) were investigated in a 15-day in vivo experiment. An analytical method was developed for the simultaneous gas chromatography/mass spectrometry determination of 14 steroids in gonads, plasma and bile. The impact of EE2 on the endocrine status of juvenile turbot was sex-dependent, since males were much more sensitive than females. Even at very low concentration (3.5 ng l(-1)), EE2 depressed androgen production as well as plasma levels in males. Androstenedione and 11-ketotestosterone were highly affected by EE2-exposure, since their production was suppressed in EE2-treated males. Furthermore, testis estrogen production and conjugation increased as a consequence of EE2 exposure. Overall, the ratio of androgens to estrogens in EE2-exposed males dropped in testis and plasma and reached values observed in females. These results indicate that juvenile male turbots are susceptible to hormonal imbalance as a consequence of short-term exposure to environmentally relevant EE2 levels.

Determination of steroidal hormone profiles along the Jalle d'Eysines River (near Bordeaux, France)

Steroidal estrogens have been shown to be the main contributors to the estrogenic activity observed in aquatic systems contaminated with sewage treatment work effluents. Although the occurrence of steroid hormones in the environment has received a great deal of attention, little is known about their fate in aquatic systems. In the presentwork, concentrations of conjugated and unconjugated hormonal steroids (estrone, 17beta-estradiol, estriol, 17alpha-ethynylestradiol, mestranol, progesterone, norethindrone, and D-norgestrel) were determined in the effluent of the Eysines sewage treatment plant (near Bordeaux, France), and along the receiving river, the Jalle d'Eysines River. Sampling was undertaken in summer and in winter conditions, to study both the temporal and the spatial distributions of steroids in this river. Only unconjugated natural estrogens were detected in the effluent. Estrone was the dominant compound (detected in all effluent samples, 17.1-71.0 ng x L(-1)), while estradiol and its metabolite estriol were detected only once, at much lower levels (4.4 and 2.9 ng x L(-1), respectively). Levels of estrogens were clearly raised above the detection limits downstream of the Eysines STP effluent discharge. Seasonal variations of estrone degradation rates were observed. In summer, the apparent decay rates of estrogen levels exceeded that of dilution, indicating high removal rates from the water column: 50% of the initial amount of this steroid was degraded within 1.7 km downstream of the effluent discharge. In winter, however, estrone levels did not significantly decrease over a 10 km reach downstream of the effluent discharge (1.9-1.8 ng x L(-1)). Steroids were determined in the particulate material of the river, but levels were below the detection limits (0.4-1.9 ng x g(-1)), indicating that sorption was not a major sink of estrogens. Therefore, it is likely that biodegradation plays a major role in the removal of steroids from the river and the different decay rates are probably related to differences in bacterial activity within the river.

Estimating steroid oestrogen inputs into activated sludge treatment works and observations on their removal from the effluent

A method to predict steroid oestrogen inputs into sewage works is described and tested against available data. For oestradiol (E2), 68% of the predictions were within 50% of the actual measured value, and for oestrone (E1), 52% of the estimations were within 50% of the measured value. Predictions for ethinyloestradiol (EE2), which are particularly sensitive to assumptions on the number of people taking the oral contraceptive, were less accurate. Five Italian and three Dutch activated sludge treatment works (STW) were sampled on two to three occasions for E2, E1, EE2 and E3 (E3 only in Italy) in both influent and effluent waters. High concentrations of E3 were found in the influent, as predicted, with a mean of 57 ng/1 and a mean of 10 ng/l in the effluent. Using the currently available data collected from composite samples, an average of 88% of E2 and 74% of E1 would appear to be removed by the activated sludge process.

Aromatization and hydrolysis of norethisterone-3-oxime in rabbit

Two pharmacologically active metabolites, norethisterone (NET) and ethinylestradiol (EE2), were detected by HPLC and HPLC-RIA methods in rabbit plasma following single i.v. and i.g. administration at a dose of 1 mg/20 microCi/kg of [3H]norethisterone-3-oxime (NETO). Approximately 48% (i.v. injection) and 91% (i.g. administration) of the NETO dose were hydrolyzed to NET. Although only 0.35% of the NETO dose was aromatized to EE2, due to its high estrogenic potency, EE2 might contribute to the overall pharmacological pattern of NETO in the rabbit.

Pharmacokinetics, hydrolysis and aromatisation of norethisterone-3-oxime in female cynomolgus monkey

Norethisterone-3-oxime (NETO) was administered to 3 female cynomolgus monkeys intragastrically and, after a wash-out period of 2-5 weeks, intravenously at a dose of 1 mg/kg. The radioactive dose of tritiated NETO was 20 microCi/kg for both treatments. For i.v. injection, a 30% propylene glycol/water solution and for i.g. administration an aqueous microcrystalline suspension was used. Excretion of radiolabel in urine and feces was followed for 5 days and plasma samples were obtained up to 2 days after administrations. In all samples (urine, feces and plasma) radioactivity was determined. Extracts from plasma samples were subjected to HPLC separation of drug and metabolites, as well as NETO and NET (metabolite of NETO after hydrolysis of the oxime group) levels were determined. In addition, EE2 (ethinylestradiol, A-ring aromatised metabolite of NET) levels were estimated using a specifically designed HPLC system for separation. Quantification of EE2 was achieved by radioimmunoassay (RIA) of specific eluate fractions. The results demonstrate that [3H]-NETO was absorbed completely at a dose level of 1 mg/kg, and excreted predominantly via the kidneys. A urinary to fecal excretion ratio of 1.5 (i.v.) or 1.0 (i.g.) was found. Renal excretion of total radiolabel proceeded with a half-life of about 0.8 (i.v.) or 1.1 (i.g.) days. Balances were incomplete, probably due to technical reasons. Orally administered NETO was highly bioavailable (84.0 +/- 16.9% of dose) but rapidly cleared from plasma (total clearance corresponded to 97% of plasma liver flow). The clearance from plasma is equivalent to the metabolic clearance because almost no unchanged NETO is excreted. Extensive metabolism of the parent drug was observed leading to at least two pharmacologically active metabolites (NET, EE2). The main progestogenic metabolite was NET reaching similar high plasma levels as NETO. EE2 turned out to be a metabolite of NETO and a conversion rate of below 0.5% of dose was estimated. However, due to its high estrogenic potency EE2 might contribute to the overall pharmacological pattern of NETO in the cynomolgus monkey.

Uterine abnormalities in rats exposed neonatally to diethylstilbestrol, ethynylestradiol, or clomiphene citrate

The toxicity of the synthetic estrogens diethylstilbestrol (DES), and ethynylestradiol (EE), and the antiestrogen clomiphene citrate (CC) was evaluated by assessing postnatal uterine growth and development prior to the onset of puberty in the rat. Both DES and EE, administered during the neonatal period (postnatal days 1-5), initially increased uterine weight and luminal epithelium hypertrophy. However, uterine weight declined in both DES- and EE-treated animals and fell below controls beyond day 11. Luminal epithelium stimulation generally paralleled uterine weight changes. Precocious development of uterine glands occurred after estrogenization (compared to untreated controls), but subsequently gland numbers were approximately 60% of control levels. Neonatal CC exposure induced only slight uterine weight gain but caused prolonged luminal epithelium hypertrophy and inhibited uterine gland genesis. Luminal epithelium hypertrophy appears to be a useful measure of antiestrogen activity. These data demonstrate the toxicity of DES and EE as assessed by altered prepubertal uterine gland development. Additionally, the inhibition of uterine gland genesis after neonatal CC exposure occurs in conjunction with prolonged luminal epithelium hypertrophy.

Metabolic profiles of endogenous and ethynyl steroids in plasma and urine from women during administration of oral contraceptives

Conjugated ethynyl and endogenous steroids in plasma and urine from two women taking an oral contraceptive (Conlumin) containing 1 mg norethindrone and 50 micrograms mestranol have been analyzed by methods based on anion and ligand exchange chromatography and gas chromatography-mass spectrometry. Conjugated norethindrone and its reduced metabolites with 3 alpha,5 alpha, 3 alpha,5 beta, 3 beta,5 beta and 3 beta,5 alpha configurations were identified in the fluids. The quantitatively major metabolites in plasma were a disulphate of the 3 alpha,5 alpha isomer and a monosulphate of the 3 alpha,5 beta isomer. The renal clearance of the former compound was low. The major urinary metabolite of norethindrone was the 3 alpha,5 beta isomer conjugated with glucuronic or sulphuric acid. Disulphates constituted only a small portion of urinary ethynyl steroids. Metabolic profiles of endogenous neutral steroids in plasma and urine during the contraceptive cycle were compared with profiles during a physiological menstrual cycle. The concentrations of steroids in plasma during contraception were similar to those during the follicular and mid phases of the menstrual cycle, whereas levels of progesterone metabolites were higher in the luteal phase. The urinary excretion of steroids was 15-30% lower during the contraceptive cycle, due to a decrease in excretion of C21O5 steroids, 11-oxygenated androgens and etiocholanolone. The increase of urinary progesterone metabolites seen during the luteal phase was not observed during contraception, but the excretion of 5 beta-pregnane-3 alpha,20 alpha-diol glucuronide was higher than during the follicular and mid phases of the menstrual cycle.

Oral contraceptives and breast cancer. In vitro effect of contraceptive steroids on human mammary cell growth

The proliferative response of human mammary epithelial cells cultured in medium containing oral contraceptive steroids, singly and in combination, was measured. Cells came from 59 normal, nonmalignant atypical, and malignant breast tissue specimens. Growth of most cultures was stimulated by the estrogens 17 beta-estradiol and ethinyl estradiol, and any combination containing ethinyl estradiol. Most (75%) malignant specimens were stimulated by one or more of the progestins, whereas none of the nonmalignant cells were. For two of the estrogen/progestin combinations found in many birth control pills, malignant cells were stimulated to grow faster than nonmalignant cells. It was concluded that oral contraceptive steroids can stimulate the growth of mammary epithelia in cell culture and might do the same in vivo. These data corroborate epidemiologic data which suggest oral contraceptives might act as tumor promoters, especially in the older user, who is more likely to have malignant cells already present in the breast.

Factors responsible for the formation of different N-alkylated porphyrins in rat liver microsomal systems exposed to norethindrone. The role of 3 alpha-hydroxysteroid dehydrogenase

Incubation of rat liver microsomes with norethindrone and a NADPH-generating system leads to the formation of one N-alkylated porphyrin (green pigment, GP1). Administration of this steroid to male rats in vivo results in the formation of three more-polar green pigments (GP2, 3 and 4). A cytosolic protein (green-pigment converting protein) has been purified from rat liver that, when added to liver microsomal mixtures containing norethindrone (0.03 mM) and a NADPH-generating system, results in the formation of all four green pigments (GP1, 2, 3 and 4). Field-desorption mass spectrometry of the purified green pigments gave protonated molecules, [M + H]+, at m/z 905 for GP1, m/z 909 for GP2, m/z 925 for GP3 and 4. The Mr of the purified cytosolic protein on SDS/polyacrylamide-gel electrophoresis or gel filtration was 37000. Polyacrylamide-gel isoelectric focusing gave a pI value of 5.9. Antibodies raised in rabbits against this protein, after preincubation with rat liver cytosol, subsequently prevented the formation of the more-polar norethindrone-induced green pigments (GP2, 3 and 4). The purified protein in the presence of either NADH or NADPH catalysed the reduction of delta 4-ring-reduced norethindrone, 5 alpha-oestran-17 alpha-ethynyl-17 beta-ol-3-one and, with the appropriate cofactor, the oxidation and reduction of steroids lacking the ethynyl function, e.g. androsterone or dihydrotestosterone. Indomethacin inhibited the reduction of dihydrotestosterone by this protein with an I50 (concn. causing 50% inhibition) value of 4.9 microM. From its physical and enzymic properties it is concluded that green-pigment converting protein is the same as 3 alpha-hydroxysteroid dehydrogenase (EC 1.1.1.50).

Destruction of cytochrome P-450 and formation of green pigments by contraceptive steroids in rat hepatocyte suspensions

The contraceptive steroid norethindrone caused a rapid time and dose-dependent loss of cytochrome P-450 from rat hepatocytes in suspension cultures. Up to 30% of this cytochrome was lost in the first 5 min of incubation; longer incubations resulted in little further loss even though not all the steroid was metabolised and the cells remained viable. Such cultures were used to investigate the formation of N-alkylated porphyrins (green pigments) which could be extracted from cell incubation mixtures following exposure to norethindrone and separation by HPLC or TLC. The number of N-alkylated porphyrins formed was dependent both on the time of incubation and the concentration of steroid. After 1 min, 1 major green pigment (GP1) was resolved using either high (0.3 mM) or low (0.03 mM) norethindrone concentrations. With longer incubation times (60 min), at high steroid concentrations, only one additional polar adduct (GP2) was formed. At lower steroid levels, 3 more polar components (GP2, 3 and 4) were seen. As judged by HPLC or TLC, GP1 corresponds to the pigment formed in microsomal preparations incubated with norethindrone in vitro, while GP2, 3 and 4 correspond to the pigments extracted from the livers of rats administered this steroid in vivo. Pretreatment of rats with either phenobarbitone or 3-methylcholanthrene induced cytochrome P-450s. Relative to controls, phenobarbitone pretreatment also resulted in a greater accumulation of green pigments in hepatocytes incubated with norethindrone, the more polar forms of green pigments (GP3 and 4), showing a disproportionate increase in concentration. The mixed function oxidase inhibitor SKF 525-A or high concentrations of steroid not containing an ethynyl function, e.g. norethandrolone, when added to cell cultures containing norethindrone, preferentially inhibited the formation of GP3 and 4. When purified green pigments were added to cell incubation mixtures in the absence of norethindrone, preferentially inhibited the formation of GP3 and 4. When purified green pigments were added to cell incubation mixtures in the absence of norethindrone, no interconversion of one form to another could be demonstrated. The results suggest that the more polar norethindrone-protoporphyrin IX adducts (GP2, 3 and 4) arise as a result of metabolic modification of norethindrone rather than the protoporphyrin IX moiety, either prior to or after activation of the ethynyl function. The formation of several green pigment components in hepatocyte suspensions was not unique to norethindrone but occurred with a number of other 17-ethynyl-substituted steroids.

The photochemical decomposition of the progestogenic 19-norsteroid, norethisterone, in aqueous medium

Norethisterone, a contraceptive 19-norsteroid, was decomposed in aqueous medium (pH 7.4) by UV-B radiation (280-320 nm). This 4-en-3-oxo-19-norsteroid was not prone to the skeletal rearrangement reactions usually observed in steroids possessing a C10-methyl group. Under the reaction conditions applied, products were formed by addition of molecules, such as solvent molecules or a second steroid molecule, and by reduction of the double bond. The prevalence of addition type reactions may have consequences for the application of norethisterone-like steroids in subdermal contraceptive devices.

Investigation into the effects of the photodecomposition of norethisterone by UV-B light on Salmonella typhimurium TA98 and the rat

In view of the light-induced side-effects of the oral contraceptive pill and the development of injectable and subdermal contraceptive devices, the effects of norethisterone irradiated with UV-B light (280-320 nm) on the microorganism Salmonella typhimurium TA98 and male Wistar rats have been investigated. The observed cytotoxic effect of the photo-products on Salmonella typhimurium TA98 may in part be caused by the irreversible binding of steroid to protein from this bacterium, of which binding is in line with previous experiments. However, after intraperitoneal or percutaneous administration of 4-14C-norethisterone to rats, followed by irradiation with UV-B light, no significantly higher level of radioactivity was observed in blood, organ material of the skin, kidney or liver, on extraction or dialysis of the samples.

Relative potency of progestins used in oral contraceptives

Epidemiologic studies indicate that the risk of complications with oral contraceptive use is related to the steroid content and potency of the various formulations. This paper summarizes human data in which potencies of progestins in oral contraceptives can be compared. Data on delay of menses and endometrial subnuclear vacuolization, an indirect assessment of glycogen deposition, are presented. The relative effects of various progestins on serum lipids and lipoproteins are also summarized. The object of this review is to examine the available scientific evidence which generally supports the conclusion that there is a marked similarity of potency of the dose of various progestins used in many of the formulations currently available in the U.S. The progestins norethindrone, norethindrone acetate and ethynodiol diacetate are roughly equivalent in potency while norgestrel is roughly five to ten times and levonorgestrel ten to 20 times as potent.

Teratogenicity and embryotoxicity of orally administered lynestrenol in rabbits

Pregnant Belted Dutch rabbits were administered lynestrenol 17-alpha-ethynyl-oestr-4-en-17-beta-ol) orally on days 6-18 of gestation at doses of 0.1, 0.5, and 2.5 mg/kg/day. On day 29 of gestation the does were killed and autopsied and the fetuses were examined for external, visceral and skeletal abnormalities. Lynestrenol administration produced a statistically significant increase in the number of post-implantation loss (p = 0.05) and in the average per cent of abnormal fetuses per dose group (63%, 66%, and 87% for the medicated group, versus 12% for the placebo group, p = 0.05). None of the doses tested was lethal to the does, but the average weight gain was decreased for the medium and the high dose groups. Abnormalities of the central nervous system and skeletal variants were the most frequent findings in the fetuses.

Analysis of isomeric ethynylestradiol glucuronides in urine

A method for separation and analysis of conjugates of ethynylestradiol in urine is described. Steroid conjugates are separated on a lipophilic strong anion exchanger (triethylaminohydroxypropyl Sephadex LH-230), and phenolic steroids released by enzyme hydrolysis or solvolysis ar isolated by chromatography on the same ion exchanger. Steroids carrying an ethynyl group are isolated by chromatography on SP-Sephadex (Ag+). Ethynylestradiol is analyzed by gas chromatography-mass spectrometry of the trimethylsilyl ether, using [9,11,11,12,12-(2)H5] ethynylestradiol and internal standard.

A randomized study of metabolic effects of four low-estrogen oral contraceptives: I. Results after 6 cycles

Healthy, non-smoking, normotensive, well-motivated young women were assigned at random to one of four different, commercial, low-estrogen, oral contraceptive products. Measurements of biochemical parameters were made on blood specimens collected from fasting subjects twice during the late pretreatment cycle, then again during each late treatment cycle for six months. All women assigned to one product (0.5mg NET + 35 microgram EE) dropped out of the study before the end of the fifth cycle, but discontinuations with the other three products were few. While numbers of subjects are small, the groups are closely matched and most metabolic differences are statistically significant. Products containing EDA and NET were associated with increases in serum total cholesterol and triglycerides, but decreases in HDL-cholesterol. In contrast, the LNG-containing preparation produced significantly less effect on these tests. A similar pattern was seen with a range of blood coagulation and fibrinolytic factors, Minimal alterations were seen with the LNG preparation, while those containing NET or EDA showed marked increases in factors I. VII, VIII, X and plasminogen, associated with a decrease in antithrombin III. It is suggested that differences in the metabolic impact of the various commercially available low-estrogen preparations, combined with effects on intermenstrual bleeding, allow a choice of the progestogen component most suitable for general use.

Chemical reactivity and metabolism of norethindrone-4 beta,5 beta-epoxide by rat liver microsomes in vitro

A method has been developed to separate norethindrone and norethindrone-4 beta,5 beta-epoxide by high performance liquid chromatography using isocratic solvent systems with either ODS-reverse phase or conventional silica gel columns. Using these techniques it was found that norethindrone epoxide, prepared chemically, was stable in aqueous buffer (pH 7.4) at 37 degrees C for at least 1 h. Under similar conditions, in the presence of a 10-fold molar excess of cysteine or glutathione, the half life for norethindrone epoxide was 15 and 32 min respectively. In 0.01 M perchloric acid at 37 degrees C the t 1/2 of norethindrone epoxide was 17 min. Norethindrone epoxide was rapidly degraded by rat liver microsomal epoxide hydratase to give a metabolite having properties consistant with it being norethindrone-4,5-dihydrodiol. Epoxide hydratase activities were stimulated about three fold by pretreating rats with phenobarbitone. The pH optimum for this reaction was pH 7.4. Conversion of norethindrone epoxide to norethindrone-dihydrodiol was inhibited by the epoxide hydratase inhibitor 1,2-epoxytrichloropropane. Although norethindrone was extensively metabolised in the presence of NADPH and rat liver microsomes, no conversion to norethindrone-4 beta,5 beta-epoxide could be demonstrated, either in the presence or absence of epoxytrichloropropane in the reaction mixture. If norethindrone epoxide was produced under these conditions it was suggested that it either reacted with microsomal proteins at or close to the site or production or was further metabolised. Norethindrone-4 beta,5 beta-epoxide did not cause any loss of cytochrome P-450 when incubated with rat liver microsomes in the absence of NADPH. Only in the presence of NADPH did further metabolism of norethindrone epoxide occur leading to the formation of active metabolites capable of breaking down cytochrome P-450. The initial rate of loss of cytochrome P-450 under these conditions was greater with norethindrone than with norethindrone epoxide as the substrate.