Metabolism of the aromatase inhibitor 4-hydroxy-4-androstene-3,17-dione by male rhesus monkeys.
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The steroids 7 alpha,17 beta-dihydroxy-5 alpha-androstan-3-one (7 alpha-hydroxy-Dht), 5 alpha-androstan-3 alpha,7 alpha,17 beta-triol (7 alpha-hydroxy-3 alpha-A'DIOL) and 5 alpha-androstane-3 beta,7 alpha,17 beta-triol (7 alpha-hydroxy-3 beta-A'DIOL) have been synthetized from 7 alpha,17 beta-dihydroxy-4-androsten-3-one (7 alpha-hydroxy-testosterone). The effect of administering 7 alpha-hydroxy-Dht, 7 alpha-hydroxy-3 alpha-A'DIOL or 7 alpha-hydroxy-3 beta-A'DIOL on serum levels of LH, FSH and on ventral prostate and seminal vesicle weight were investigated in gonadectomized adult male rats. Each steroid was administered for seven days in a dose of 300 micrograms per day. No suppression of serum LH or FSH levels was recorded following injections of these 7 alpha-hydroxylated steroids to castrated rats, compared to castrated control rats receiving vehicle only. Administration of 7 alpha-hydroxy-Dht or 7 alpha-hydroxy-3 alpha-A'DIOL to castrated mature rats could maintain ventral prostate and seminal vesicle weights above that of castrated control rats. Administration of 7 alpha-hydroxy-3 beta-A'DIOL to castrated mature rats resulted in ventral prostate weights slightly above castrate control levels, while seminal vesicle weight in such rats were in the same range as castrated control rats. Intraperitoneal administration of testosterone or of 5 alpha-androstane-3 beta,17 beta-diol (3 beta-A'DIOL) to castrated rats maintained activity of the androgen dependent isoenzyme of acid phosphatase in the ventral prostate; 7 alpha-hydroxy-testosterone or 7 alpha-hydroxy-3 beta-A'DIOL showed, however, no effect on this enzymic activity.
From incubations of testosterone with rat testicular homogenates in the presence of a NADPH-generating system, the following 7 alpha-hydroxylated metabolites could be isolated and identified: 7 alpha, 17 beta-dihydroxy-4-androsten-3-one (7 alpha-hydroxy-testosterone), 7 alpha-17 beta-dihydroxy-5 alpha-androstan-3-one (7 alpha-hydroxy-Dht), 5 alpha-androstan-3 alpha, 7 alpha, 17 beta-triol (7 alpha-hydroxy-3 alpha-A'DIOL) and 5 alpha-androstane-3 beta, 7 alpha, 17 beta-triol (7 alpha-hydroxy-3 beta-A'DIOL). To our knowledge this is the first demonstration of the formation of 5 alpha-reduced-7 alpha-hydroxylated metabolites of testosterone in the male gonad. These 5 alpha-reduced-7 alpha-hydroxylated metabolites could also be isolated after incubations of 5 alpha-androstane-3 alpha, 17 beta-diol (3 alpha-A'DIOL) with testicular homogenates in the presence of A NADPH-generating system. Measured as the sum of 7 alpha-hydroxy-testosterone, 7 alpha-hydroxy-Dht. 7 alpha-hydroxy-3 alpha-A'DIOL and 7 alpha-hydroxy-3 beta-A'DIOL formed using testosterone as substrate, total 7 alpha-hydroxylase activity was six times higher in testes of mature rats than in testes from animals 23 days old. With 3 alpha-A'DIOL as substrate total 7 alpha-hydroxylase in the mature testis was about three times greater than in the sexually immature testis.
A new method for the simultaneous determination of androstenedione, testosterone, 11-oxotestosterone and 11 beta-hydroxy-testosterone in teleost plasma has been developed. Steroids extracted from the plasma were first separated by Celite chromatography using ethanediol as the stationary phase and different concentrations of ethyl acetate in iso-octane as the eluting solvents. Androstenedione, testosterone, 11-oxotestosterone and 11 beta-OH-testosterone were eluted successively with 0, 10, 15 and 40% of ethyl acetate in iso-octane. The eluted steroid fractions were then quantatively determined by radioimmunoassay. Data on the accuracy, precision, and sensitivity were presented showing that this new assay system was precise and reproducible. As an illustration of its application, this method was used in the present study to determine the plasma androgen levels in Monopterus albus and in methyl-testosterone treated Tilapia mossambicus.
9 alpha-Hydroxyandrost-4-ene-3,17-dione 1, when allowed to react with dipotassium acetylide in tetrahydrofuran, resulted, after chromatographic separation, in 4-methyl-19-norandrosta-4,9-diene-1,17-dione 2, 4 xi-methyl-19-norandrosta-5(10),9(11)-diene-1,17-dione 3, 4-methyl-17 alpha-ethynyl-17 beta-hydroxy-19-norandrosta-4,9-dien-1-one 4, 4 xi-methyl-17 alpha-ethynyl-17 beta-hydroxy-19-norandrosta-5(10),9(11)-dien- 1-one 5, and 17 alpha-ethynyl-17 beta-hydroxy-9,10-secoandrost-4-ene-3,9-dione 6. Selective protection of delta 4-3-ketone of 9 alpha-hydroxyandrost-4-ene-3,17-dione 1 as its dienol methyl ether 7, and subsequent reaction with lithium acetylide-ethylenediamine followed by acidic hydrolysis, afforded 9 alpha,17 beta-dihydroxy-17 alpha- ethynylandrost-4-en-3-one 8.
Practical routes to 9 alpha-hydroxypregnenes were developed by epimerization and hydration of 17 alpha-ethynyl-9 alpha,17 beta-dihydroxyandrost-4-en-3-one. In the three different methods of epimerization which were used, the C-9 alpha hydroxy group was not susceptible to rearrangement or other side reactions. C-21 functionalized 9 alpha-hydroxypregnenes were obtained by introducing a 17 alpha-halogenated ethynyl group into 9 alpha-hydroxyandrost-4-ene-3,17-dione. Epimerization and hydration by the 17 beta-nitrooxy method produced 21-halogenated 9 alpha-hydroxypregnenes, which were further converted into 21-acetoxy-9 alpha-hydroxypregn-4-ene-3,20-dione.
The microorganism Mucor piriformis transforms androst-4-ene-3,17-dione into a major and several minor metabolites. X-ray crystallographic analysis of two of these metabolites was undertaken to determine unambiguously their composition and chirality. Crystals belong to the orthorhombic space-group P2(1)2(1)2(1), with a = 7.199(4) A and a = 6.023(3) A, b = 11.719(3) A and b = 13.455(4) A, c = 20.409(3) A and c = 20.702(4) A for the two title compounds, respectively. The structures have been refined to final R values of 0.060 and 0.040, respectively.
Hydroxylation at position 6 beta testosterone I (17 beta-hydroxyandrost-4-en-3-one) and the anabolic steroids 17 alpha-methyltestosterone II (17 beta-hydroxy-17 alpha-methylandrost-4-en-3-one), metandienone III (17 beta-hydroxy-17 alpha-methylandrosta-1,4-dien-3-one), 4-chloro-1,2-dehydro-17 alpha-methyltestosterone IV (4-chloro-17 beta-hydroxy-17 alpha-methylandrosta-1,4-dien-3-one), and fluoxymesterone V (9-fluoro-11 beta, 17 beta-dihydroxy-17 alpha-methylandrost-4-en-3-one) was achieved via light-induced autooxidation of the corresponding trimethysilyl 3,5-dienol ethers dissolved in isopropanol or ethanol. The reaction further yielded the 6 alpha-hydroxy isomer in low amounts. The 6 beta-hydroxy isomer of I-V and the 6 alpha-hydroxy isomers of I, III, and IV were isolated and characterized by 1H and 13C NMR, high-performance liquid chromatography, gas chromatography, and mass spectrometry. Human excretion studies with single administered doses of boldenone (17 beta-hydroxyandrosta-1,4-dien-3-one), 4-chloro-1,2-dehydro-17 alpha-methyltestosterone, fluoxymesterone, metandienone, 17 alpha-methyltestosterone, and [16,16,17-2H3] testosterone showed that 6 beta-hydroxylation is the major metabolic pathway in the metabolism of 4-chloro-1,2-dehydro-17 alpha-methyltestosterone, fluoxymesterone, and metandienone, whereas for boldenone, 17 alpha-methyltestosterone, and testosterone, 6 beta-hydroxylation is negligible.
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Our previous studies have shown that even in the absence of estrogen, the estrogen receptor (ER) is still involved in growth by way of its conversion to a transcriptionally active state by growth inducing cytokines. The following paper now provides evidence that under more physiological conditions, the ER within the GH3 cell line used for the previous investigations, not only controls growth, but that transcriptional activity of the receptor is required for cell survival. Therefore when GH3 cells, maintained under serum and steroid replete conditions, are exposed to the pure antiestrogen ZM 182780 (10 nM), marked cell death is observed 72-120 h after first exposure. Studies on the nature of this cell death suggested that it had some of the reported characteristics of apoptosis or programmed cell death. Removal of steroids from the culture medium also resulted in cell death and this was enhanced by the addition of the pure antiestrogen. Both steroid withdrawal and ZM 182780 induced cell death was completely reversed by the inclusion of estrogens in the steroid free culture medium. In contrast, the non-steroidal antiestrogen, 4-hydroxytamoxifen (4-OHT) was not able to enhance steroid withdrawal death and at 1 microM, this compound was shown to have marked ER agonist activity. Further studies on the addition of conditioned medium from high density GH3 cell cultures, to low density steroid free cells, strongly suggested that the ER within these cells was responsible for the production of autocrine/paracrine survival factors.
A chicken B lymphoma line, DT40, hypermutates immunoglobulin (Ig) genes spontaneously during culture. Thus, cultured DT 40 cells constitute a useful Ig library for screening antibodies (Abs) in vitro. To fix desirable Ig mutants by stopping hypermutation or to resume mutation for further improvement of Ab affinity, activation-induced cytidine deaminase (AID), a key enzyme responsible for the Ig mutation machinery, must be switched on or off. To this end, we generated a DT40 line whose one AID allele was disrupted, and the other allele was replaced by the loxP-flanked AID construct. In this engineered cell line designated as DT40-SW, AID expression could be switched reversibly by tamoxifen-regulated Cre recombinase. Devices were also introduced to discriminate between the "AID-ON" and the "AID-OFF" cells by GFP expression and puromycin resistance, respectively. Starting from a single DT40-SW cell, Ig gene repertoire was efficiently diversified during culture only when AID expression was on.
Transplantation of neural stem cells into the brain is a novel approach to the treatment of chronic stroke disability. For clinical application, safety and efficacy of defined, stable cell lines produced under GMP conditions are required. To this end, a human neural stem cell line, CTX0E03, was derived from human somatic stem cells following genetic modification with a conditional immortalizing gene, c-mycER(TAM). This transgene generates a fusion protein that stimulates cell proliferation in the presence of a synthetic drug 4-hydroxy-tamoxifen (4-OHT). The cell line is clonal, expands rapidly in culture (doubling time 50-60 h) and has a normal human karyotype (46 XY). In the absence of growth factors and 4-OHT, the cells undergo growth arrest and differentiate into neurons and astrocytes. Transplantation of CTX0E03 in a rat model of stroke (MCAo) caused statistically significant improvements in both sensorimotor function and gross motor asymmetry at 6-12 weeks post-grafting. In addition, cell migration and long-term survival in vivo were not associated with significant cell proliferation. These data indicate that CTX0E03 has the appropriate biological and manufacturing characteristics necessary for development as a therapeutic cell line.
We have identified novel estrogen receptor alpha (ERalpha) antagonists using both cell-based and computer-based virtual screening strategies. A mammalian two-hybrid screen was used to select compounds that disrupt the interaction between the ERalpha ligand binding domain (LBD) and the coactivator SRC-3. A virtual screen was designed to select compounds that fit onto the LxxLL peptide-binding surface of the receptor, based on the X-ray crystal structure of the ERalpha LBD complexed with a LxxLL peptide. All selected compounds effectively inhibited 17-beta-estradiol induced coactivator recruitment with potency ranging from nano-molar to micromolar. However, in contrast to classical ER antagonists, these novel inhibitors poorly displace estradiol in the ER-ligand competition assay. Nuclear magnetic resonance (NMR) suggested direct binding of these compounds to the receptors pre-complexed with estradiol and further demonstrated that no estradiol displacement occurred. Partial proteolytic enzyme digestion revealed that, when compared with 17-beta-estradiol- and 4 hydroxy-tamoxifen (4-OHT) bound receptors, at least one of these compounds might induce a unique receptor conformation. These small molecules may represent new classes of ER antagonists, and may have the potential to provide an alternative for the current anti-estrogen therapy.
The progesterone 17alpha-hydroxylase activity, which is one of the steroidogenic enzymes in rat testis microsomes, was significantly inhibited by crude marijuana extracts from Delta(9)-tetrahydrocannabinolic acid (THCA)- and cannabidiolic acid (CBDA)-strains. Delta(9)-Tetrahydrocannabinol, cannabidiol and cannabinol also inhibited the enzymatic activity with relatively higher concentration (100-1000 microM). Testosterone 6beta- and 16alpha-hydroxylase activities together with androstenedione formation from testosterone in rat liver microsomes were also significantly inhibited by the crude marijuana extracts and the cannabinoids. Crude marijuana extracts (1 and 10 microg/ml) of THCA strain stimulated the proliferation of MCF-7 cells, although the purified cannabinoids (THC, CBD and CBN) did not show significant effects, such as the extract at the concentration of 0.01-1000 nM. These results indicate that there are some metabolic interactions between cannabinoid and steroid metabolism and that the constituents showing estrogen-like activity exist in marijuana.
Most, but not all, studies have found that women with a high urinary 2-hydroxyestrogen (2OHE) to 16alpha-hydroxyestrone (16alphaOHE1) ratio are at reduced risk for breast cancer and have a better prognosis. The aim was to identify factors associated with the pre-operative 2OHE to 16alphaOHE1 ratio and factors that predicted the change in the ratio between the pre-operative visit and first follow-up visit three to six months post-operatively among 59 women with primary ER positive breast cancer tumors. Body measurements, questionnaires and blood samples for measurements of the 2OHE and 16alphaOHE1 plasma levels and CYP1A2 *1F genotyping were collected at both visits. Post-operatively, 15 women received tamoxifen, 30 women tamoxifen and radiotherapy concomitantly, and 14 women radiotherapy. The pre-operative ratio was not correlated with tumor characteristics, but was significantly higher in women who consumed three or more cups of coffee daily (p = 0.009). The number of CYP1A2 *1F C-alleles was correlated with a lower ratio at both visits (p = 0.13 and p = 0.02, respectively). The ratio increased between the two visits in 69.5% of the women. The factors associated with a significant increase in the ratio were concomitant tamoxifen and radiotherapy (p = 0.006), increasing alcohol consumption (p = 0.006), and a high coffee consumption (p = 0.03), but not age or CYP1A2 *1F genotype. In this pilot study, breast cancer patients who started tamoxifen during radiotherapy and who had a moderate coffee and alcohol consumption demonstrated a significant improvement in their estrogen metabolite profile between the pre- and post-operative visits.
Two methods have been developed for efficient conversion of pregna-14,16-dien-20-ones into 14 beta-hydroxyandrost-15-en-17-ones. One procedure consists of treatment of the ring-D dienone successively with sodium borohydride and singlet oxygen. The reaction is illustrated by the conversion of pregna-14,16-dien-20-one 1 into 14 beta-hydroxyandrost-15-en-17-one 3, via the corresponding allylic alcohol 2. Although this two-step procedure is simple, it provides 3 in relatively low yield, accompanied by a smaller amount of the isomeric 14 alpha-hydroxyandrost-15-en-17-one 6. An alternative one-step conversion is achieved by treatment of dienone 1 with a peroxyacid in the presence of a strong protic acid. This process is illustrated by the two-step conversion of dienone 1 into hydroxy ketone 11 in 51% overall yield (Scheme 5) and by the analogous conversion of dienone 13 into hydroxy ketone 24 in 61% overall yield (Scheme 11).
PURPOSE: The hepatic and intestinal metabolic activities of P450 were evaluated in rats with surgery- and drug-induced renal dysfunction. METHODS: Renal failure was induced by five-sixths nephrectomy (NR), bilateral ureter ligation (BUL), the intramuscular injection of glycerol (GL), and the intraperitoneal injection of cisplatin (CDDP). Phenytoin 4-hydroxylation, debrisoquine 4-hydroxylation, and testosterone 6beta-hydroxylation were estimated to evaluate the metabolic activities of cytochrome P450 (CYP) 2C, 2D, and 3A, respectively. RESULTS: The hepatic CYP3A metabolic activities were decreased by 65.9% and 60.2% in NR and GL rats, respectively. The hepatic CYP2C metabolic activity was decreased by 48.8% in CDDP rats. No alteration in hepatic drug-metabolizing activities was observed in BUL rats. On the other hand, the intestinal CYP3A metabolic activity was weakly increased in GL rats but not significantly altered in NR, CDDP, and BUL rats. CONCLUSIONS: This study suggested (a) that only selected P450 metabolic activity in the liver is decreased in renal failure, (b) that extent of the decrease in hepatic metabolic activities of P450 is dependent on the etiology of renal failure, and (c) that alteration of CYP3A metabolic activity in the intestine is not always correlated with that in the liver.