Occurrence and seasonal variation of equine estrogens, equilin and equilenin, in the river water of Japan: Implication with endocrine-disrupting potentials to Japanese medaka (Oryzias latipes)

In this study, we determined the concentration of equine estrogens, such as equilin (Eq) and equilenin (Eqn), in the river water collected from nine research stations in Hokkaido, Japan. The LC-MS/MS analysis revealed that Eq concentrations were 2.7 ± 6.7, 0.22 ± 0.12, and 1.2 ± 0.64 ng/L in Sep 2015, Feb 2016, and Jul 2016, respectively. Eqn had concentration levels similar to those of Eq. Comparison of the concentrations at nine research stations showed that seasonal variation was observed in the detected Eq and Eqn concentration levels. This study was the first to show the occurrences and seasonal variation of Eq and Eqn in the river water of Japan. We further investigated the reproductive and transgenerational effects of Eq in Japanese medaka (Oryzias latipes) exposed to 10, 100, and 1000 ng/L for 21 days and assessed the transcriptional profiles of the estrogen-responsive genes in the livers of both sexes. The reproduction assay demonstrated that 1000 ng/L of Eq adversely affected the reproduction (i.e. fecundity) in the F₀ generation and that the hatching of F₁ generation fertilized eggs was reduced in the 100 and 1000 ng/L treatment groups. Our qRT-PCR assay revealed that the mRNA expression levels of hepatic vitellogenin 1 and 2, choriogenin L and H, and estrogen receptor α were significantly up-regulated in males exposed to 100 and/or 1000 ng/L of Eq. In contrast, the transcriptional levels of several genes, such as pregnane X receptor and cytochrome P450 3A, were down-regulated in the livers of males after the 21-d exposure. These results suggest that Eq has endocrine-disrupting potential such as reproductive and transgenerational effects by the modulation of hepatic estrogen-responsive genes expression on medaka.

Differentiating isobaric steroid hormone metabolites using multi-stage tandem mass spectrometry

Steroid hormones and their metabolites are currently undergoing clinical trials as potential therapeutics for traumatic brain injury (TBI). To support this work, it is necessary to develop improved procedures for differentiating isobaric species in this compound class. Equilin sulfate (E-S), estrone sulfate (E1-S), 17α-dihydroequilin sulfate (ADHE-S), and 17β-dihydroequilin sulfate (BDHE-S) are primary constituents in hormone replacement therapies, such as Premarin, which are among pharmaceuticals being investigated for TBI treatment. The latter three compounds are isomers and can be difficult to differentiate in trace analytical determinations. In this work, a systematic study of the fragmentation of ADHE-S, BDHE-S, E1-S, and E-S under different stages of higher order tandem mass spectrometry (MS(n)) and variation of collision energy, allowed optimization of conditions for distinguishing the isomeric structures. For epimeric variants (e.g., ADHE-S versus BDHE-S; α- versus β-stereoisomerization in the C-17 position), differentiation was achieved at MS(4) and fragmentation was demonstrated through MS(5). Computational analysis was performed to further explore differences in the fragmentation pathways due to changes in stereochemistry.

Occurrence of estrogen hormones in biosolids, animal manure and mushroom compost

The presence of natural estrogen hormones as trace concentrations in the environment has been reported by many researchers and is of growing concern due to its possible adverse effects on the ecosystem. In this study, municipal biosolids, poultry manure (PM) and cow manure (CM), and spent mushroom compost (SMC) were analyzed for the presence of seven estrogen hormones. 17α-estradiol, 17β-estradiol, 17α-dihydroequilin, and estrone were detected in the sampled biosolids and manures at concentrations ranging from 6 to 462 ng/g of dry solids. 17α-estradiol, 17β-estradiol, and estrone were also detected in SMC at concentrations ranging from 4 to 28 ng/g of dry solids. Desorption experiments were simulated in the laboratory using deionized water (milli-Q), and the aqueous phase was examined for the presence of estrogen hormones to determine their desorption potential. Very low desorption of 0.4% and 0.2% estrogen hormones was observed from municipal biosolids and SMC, respectively. An estimate of total estrogen contribution from different solid waste sources is reported. Animal manures (PM and CM) contribute to a significant load of estrogen hormones in the natural environment.

Free synthetic and natural estrogen hormones in influent and effluent of three municipal wastewater treatment plants

Three municipal wastewater treatment plants (WWTPs) in southeastern Pennsylvania were sampled to determine the presence and concentrations of 12 natural and synthetic estrogen hormones in the wastewater influent and effluent. The target estrogens were 17alpha-estradiol, estrone, estriol, equilin, 17alpha-dihydroequilin, 17beta-estradiol, 17alpha-ethinyl estradiol, gestodene, norgestrel, levonorgestrel, medrogestone, and trimegestone. One WWTP uses a biofilm reactor (packed-bed trickling filter),and the other two use suspended-growth media (continuously stirred activated sludge reactor and sequential batch reactor). Estrone was detected in all the three plants; estriol and estradiol were detected at two WWTPs; and 17 alpha-dihydroequilin and 17 alpha-ethinyl estradiol were detected at one WWTP. The concentration of estrogens in the influent and effluent of the three treatment plants ranged from 1.2 to 259 ng/L and 0.5 to 49 ng/L, respectively. The percentage removal of estrogens from the aqueous phase ranged from 41 to 99%, except in the case of 17alpha-dihydroequilin; the removal of 17alpha-dihydroequilin was negligible. The suspended-growth media systems showed higher removal efficiencies for estrogens than the biofilm system. The analytical method uses a Varian C-18 solid-phase extraction (Varian Inc., Palo Alto, California), followed by a derivatization with bis(trimethylsilyl)trifluoroacetamide. The detection limits for the estrogen compounds ranged from 0.1 to 10 ng/L using a sample size of 1 L. The method recoveries ranged from 71 to 120%, and the relative standard deviation ranged from 6 to 14% for all the hormones.

Mixtures of estrogenic contaminants in bile of fish exposed to wastewater treatment works effluents

Most effluents from wastewater treatment works (WwTWs) contain estrogenic chemicals that include steroidal estrogens and xenoestrogens. We investigated the nature of mixtures of estrogenic contaminants taken up by two species of fish exposed to two WwTWs effluents. Sexually immature rainbow trout, Oncorhynchus mykiss, and sexually mature roach, Rutilus rutilus, were exposed to tap water, river water, or one of two estrogenic WwTWs effluents for up to 10 days, when the fish were sacrificed and tissues removed for chemical analysis. Estrogenic contaminants in the bile and gonads were hydrolyzed, concentrated by solid-phase extraction, and fractionated by RP-HPLC. Active fractions were detected and quantified using a yeast estrogen receptor transcription screen (YES assay) and the identities of estrogenic components in the fractions determined by GC-MS. Bile from rainbow trout exposed to either tap water or river water contained low amounts of 17beta-estradiol (E2) and estrone (E1) with a total estrogenic activity (mean+/-standard error) of 10+/-5 and 31+/-9 ng of E2 equivalents/mL (ng of E2eq/mL) for male and female fish, respectively. In effluent-exposed trout the total estrogen content of bile was considerably higher with the following composition and concentrations (ng of E2eq/mL) of individual estrogens: E2 (male, 591+/-125; female, 710+/-207), E1 (male, 338+/-75; female, 469+/-164), ethinylestradiol, EE2 (male, 32+/-2; female, 40+/-6), nonylphenol (NP) and short-chain NP polyethoxylates (male, 21+/-4; female, 22+/-3). An additional estrogenic compound, 17beta-dihydroequilenin (DHQ), was identified for the first time in effluent-exposed fish, and was present in trout bile at concentrations of (male) 40+/-9 and (female) 30+/-5 ng of E2 eq/mL. DHQ, E2, E1, and EE2, but not NP or NP polyethoxylates, were also detected in bile of effluent-exposed roach, and the concentrations of all these steroidal estrogens in ng of E2eq/mL were lower in male (E2, 62+/-2; E1, 35+/-11; EE2, 10+/-2; DHQ, 1+/-1) compared with female (E2, 740+/-197; E1, 197+/-37; EE2, 40+/-6; DHQ, 8+/-2) roach. The synthetic estrogen EE2 was also detected in the testes and ovaries of effluent-exposed roach. This study shows that a mixture of estrogenic contaminants present in WwTWs effluents bioconcentrate in fish tissues, resulting in the induction of vitellogenin, and are likely to contribute to feminizing effects in wild fish living in U.K. rivers. The composition of the mixture of estrogenic contaminants in the bile is species dependent and may determine the susceptibility of fish to the effects of exposure to estrogenic effluents.

Quantitative structure-chromatographic retention relationship study of six underivatized equine estrogens

Underivatized estrone (ES), equilin (EQ), equilenin (EQN) and their corresponding 17 alpha-diols 17 alpha-estradiol (ESD), 17 alpha-dihydroequilin (DHEQ) and 17 alpha-dihydroequilenin (DHEQN) were separated by TLC, RP-HPLC and capillary GC. Their dipole moments (mu) and Randić's connectivity indices ((1)chi) were determined as parameters of importance for the separation. The number of H atoms was taken as an additive structural parameter of importance for the quantitative structure-chromatographic retention relationship study (QSRR). Principal component analysis (PCA) was applied in order to find similarities and dissimilarities between 9 TLC and 10 RP-HPLC systems. PCA indicated that proton donor-proton acceptor interactions play the most important role for the TLC and RP-HPLC separation. The two-dimensional non-linear map of PC variables showed that the keto-estrogens (ES, EQ and EQN) and the corresponding diols (ESD, DHEQ and DHEQN) form two separate clusters. The relationship between GC retention of equine estrogens characterized by Kováts indices (KI), their (1)chi and mu was expressed by the equation KI/100 = al(1)chi+ b/mu(2) + c. The biological activity of the estrogens was related to log 1/mu(2).

Fluorodensitometric determination of conjugated estrogens in raw material and in pharmaceutical preparations

A simple, rapid and reproducible fluorodensitometric method for the determination of conjugated estrogens has been developed. The proposed procedure includes the following steps: extraction, hydrolysis of sodium sulphate esters of estrone, equilin, equilenin and their 17-alpha-hydroxy derivatives, separation of the liberated 3-phenolic steroids and in situ measurement of fluorescence. The fluorescence emission was measured after spraying the spots of estrone and estradiol with 2,4-dinitrophenyl-hydrazine in sulphuric acid-ethanol medium and equilin and 17-alpha-dihydroequilin with phosphoric acid and sodium hydroxide solution, respectively. Equilenin and 17-alpha-dihydroequilenin were determined by measuring the native fluorescence. The method applied to the determination of raw material and tablets provided results which agreed well with the stated content and the requirements of USP XXI for conjugated estrogens.

Separation and quantitation of esterified estrogens in bulk mixtures and combination drug preparations using high-performance liquid chromatography

A high-performance liquid chromatographic method for esterified estrogens is described. By using a facile acid hydrolysis extraction procedure for the sample preparation, the compounds are chromatographed as their free phenolic forms. The separation of structurally similar compounds, such as equilenin, equilin, estrone, and estradiol, was achieved with a reversed-phase column and a methanol--water mobile phase. Several samples of bulk mixtures and tablets were assayed; the results compared favorably with those obtained using the USP XIX method. The method was rapid, and the detector response was linear over a wide concentration range. A relative standard deviation of +/- 5% indicates the reliability and accuracy of the proposed method.

Determination of aqueous solubility and pKa values of estrogens

Reported estrone pKa and solubility data show wide variation. Improved experimental procedures were designed and used to obtain reproducible results. The pKa values for several estrogens and related compounds also were determined to assess the effects of structural differences on ionization. No evidence was obtained for long-range D to A ring electronic transmission affecting pKa. Significant differences in pKa values resulted only when conjugated unsaturation was added into the B ring of estrone or estradiol. The aqueous solubilities of estrone and 17alpha-estradiol were 0.8 and 3.9 microgram/ml, respectively, at 25degrees.