Biomedical subjects

R Hampl

Publications and source records attributed to R Hampl.

At least 37 records · Page 2Linked to original sources

PubMed2000

Neuroactive steroids, their precursors, and polar conjugates during parturition and postpartum in maternal and umbilical blood: 1. Identification and simultaneous determination of pregnanolone isomers.

A rapid method for the identification and measurement of four pregnanolone isomers and their polar conjugates in human plasma was developed using a simple quadrupole GC/MS system with electron impact ionization. Steroid levels were measured in the plasma of 13 and three women at delivery with subarachnoidal and epidural analgesia, respectively, and in corresponding samples of umbilical plasma. A good correlation (r=0.94, P<0.001, n=8) was found between the allopregnanolone in maternal plasma determined by GC/MS and that measured by RIA. Epipregnanolone (3beta-hydroxy-5beta-pregnan-20-one) was identified and measured for the first time in human plasma; its concentration in both maternal and umbilical plasma was much lower than that of other pregnanolone isomers. The levels of 3beta-hydroxy-pregnanolone isomers were significantly higher in the umbilical plasma than in the maternal plasma, while the differences in 3alpha-hydroxy-isomers were insignificant. The differences in conjugates were insignificant except in the case of allopregnanolone, the levels of which were lower in umbilical plasma. In all of the pregnanolone isomers, a significantly lower conjugated/unconjugated steroid ratio was found in the umbilical plasma than in the maternal plasma. The possible role of the sulfatation of pregnanolone isomers around parturition is discussed.

Adult↗

PubMed2000

[Derivatives of dehydroepiandrosterone and their changes during a one-day starvation test].

BACKGROUND: Relationship between dehydroepiandrosterone (DHEA), its sulphate (DHEAS) and various components of metabolic syndrome X have been recently discussed in several papers. Originally only DHEA or DHEAS have been considered to be responsible for all of the effects. At present mainly DHEA hydroxyderivatives (particularly 7-hydroxyisometers) are assumed to be responsible for those effects. METHODS AND RESULTS: 68 obese subjects (28 males) aged 42.6 +/- 11.1 years, with average BMI 35.7 +/- 11.6 kg/m2 were examined. Relationship between 7-alpha and 7-beta-(OH)-DHEA and various components of metabolic syndrome X have been followed in a pilot epidemiological study. Fluctuations of the hydroxyderivates level during one-day starvation test were investigated in a group of 11 obese females and compared with that of the control group (12 lean subjects with BMI 23.1 +/- 2.4 kg/m2). From the view of the metabolic syndrome X, the negative correlation between the serum levels of 7-beta-(OH)-DHEA and insulinemia (r = -0.28; p = 0.23), glycemia (r = -0.48; p < 0.001), serum level of uric acid (r = -0.35; p = 0.02) and opposite the positive correlation between the serum level of HDL-cholesterol (r = 0.42; p < 0.01) should be pointed out. The negative correlation between 7-alpha-(OH)-DHEA and age and BMI was noticed (correlation for 7-beta-(OH)-DHEA was similar). No other statistically significant correlation was found among the other monitored parameters. In 11 obese females the dynamic changes of the above-mentioned DHEA hydroxyderivatives during one-day starvation test were monitored. Changes were compared with the control group (12 lean females). Significant increases in DHEAS, 7-beta-(OH)-DHEA, and sex hormone binding globulin (SHBG) levels were observed during this test. Significant differences in dynamic changes (before and after the test) between obese and lean group have been found only in DHEAS and SHBG. CONCLUSION: We suppose that 7-beta-(OH)-DHEA (more than 7-alpha-(OH)-DHEA) is specifically related to the metabolic syndrome X and that its claimed anti-glucocorticoid effect in the immune response can play some role in its metabolic effects.

Adult↗

PubMed2000

Time-resolved fluoroimmunoassay of plasma daidzein and genistein.

We present a method for the determination of the phytoestrogens daidzein and genistein in plasma (serum). These weakly estrogenic isoflavones occur in soybeans and in smaller amounts in some other beans and plants. It has been suggested that they may afford protection against prostate and breast cancer. The method is based on time-resolved fluoroimmunoassay (TR-FIA) using a europium chelate as a label. After synthesis of 4'-O-carboxymethyl-daidzein and 4'-O-carboxymethyl-genistein the compounds are coupled to bovine serum albumin (BSA), then used as antigens to immunize rabbits. The tracers with the europium chelate are synthesized using the same 4'-O-derivative of the isoflavones. After enzymatic hydrolysis and ether extraction the immunoassay is carried out using the VICTOR 1420 multilabel counter (Wallac Oy, Turku, Finland). The antisera cross-reacted to some extent with some isoflavonoids but not with flavonoids. The cross-reactivity seems not to influence the results, which were highly specific for both compounds. The correlation coefficients between the TR-FIA methods and the reference method based on isotope dilution gas chromatography-mass spectrometry were high; r-values were about 0.95-0.99 depending on concentration. The intra-assay coefficients of variation (CV%) for daidzein and genistein at three different concentrations vary 3.2-4.5 and 3.2-4.1, respectively. The inter-assay CVs vary 5.0-6.3 and 4.5-5.3, respectively. The working ranges of the daidzein and genistein assays are 1.0-216 and 1.7-370 nmol/l, respectively. The plasma values (n = 80) of daidzein and genistein are very low in Finnish subjects (mean for daidzein, 3.8+/-6.8 and for genistein, 3.2+/-7.6 nmol/l; median value for daidzein 1.5 and for genistein 1.4 nmol/l).

Animals↗

PubMed2000

Rapid analysis of phytoestrogens in human urine by time-resolved fluoroimmunoassay.

A time-resolved fluoroimmunoassay (TR-FIA), with europium labeled phytoestrogens as tracers, was developed for the quantitative determination of enterolactone, genistein and daidzein in human urine. The aim was to create a method for the screening of large populations in order to assess the possible correlations between the urinary levels and the risk of Western diseases. After the synthesis of the 5'-carboxymethoxy derivative of enterolactone and 4'-O-carboxymethyl derivatives of daidzein and genistein, the respective compound was coupled to bovine serum albumin and then used as an antigen in the immunization of rabbits. The same derivatives of the phytoestrogen were used in preparing the europium tracers. After the enzymatic hydrolysis, the TR-FIA was carried out using the Victor 1420 multilabel counter. The method has sufficient sensitivity to measure the phytoestrogens at concentrations even below 5 nmol/l. The intra- and inter-assay coefficients of variation, at three different concentrations, varied from 1.9 to 5.3 and from 2.4 to 9.7, respectively. We measured urinary enterolactone, genistein and daidzein in 215 samples from Finnish healthy women and found that more than 50% of the values ranged between 1 and 7, <0.1 and 0.6 and below 0.6 micromol/24 h, respectively. The TR-FIA method including only a hydrolysis step gave higher values than those measured by gas chromatography-mass spectrometry (GC-MS). However, the assay results by the present method showed strong correlation with those obtained by GC-MS. It is concluded that the TR-FIA is suitable for population screening of urinary phytoestrogens.

4-Butyrolactone↗

PubMed2000

Serum concentrations of some neuroactive steroids in women suffering from mixed anxiety-depressive disorder.

Concentrations of neurosteroids may be influenced by some physiological or pathological factors. We investigated neuroactive steroids in the serum of women suffering from anxiety-depressive disorder treated with fluoxetine and in a control group, in both the follicular and the luteal phases of the menstrual cycle. Two groups of neuroactive steroids were measured by radioimmunoassays: 1) the positive allosteric modulator of GABA(A) receptors, allopregnanolone with its precursor progesterone and 2) pregnenolone sulfate and dehydroepiandrosterone sulfate (DHEAS) acting on GABA(A) receptors by an opposite mechanism. Significantly higher levels of pregnenolone sulfate (p < 0.0001) were found in patients in both phases of the menstrual cycle. Significantly higher values were recorded in pregnenolone (p < 0.001) and 17alpha-hydroxypregnenolone (p < 0.01) levels in the patients group in the follicular phase. Our results indicate that imbalance in neuroactive steroids may play a negative role in origin and course of psychiatric and neurological disorders.

17-alpha-Hydroxypregnenolone↗

PubMed2000

7-Hydroxydehydroepiandrosterone--a natural antiglucocorticoid and a candidate for steroid replacement therapy?

7-Hydroxylated metabolites of dehydroepiandrosterone (DHEA) are believed to be responsible for at least some immunomodulatory and antiglucocorticoid effects of DHEA and hence are considered candidates for hormone replacement therapy. Our experiments in vitro brought the evidence that 3beta, 7beta-dihydroxy-5-androsten-3-one (7beta-OH-DHEA), but not DHEA and its 7alpha-hydroxyisomer, could counteract the immunosuppressive effect of dexamethasone on the formation of plaques in culture of murine spleen lymphocytes. In another experiment, DHEA and after a 3-weeks pause 3beta-hydroxy-5-androstene-7,17-dione (7-oxo-DHEA) were applied transdermally to 6 male volunteers on 5 consecutive days. Blood levels of DHEA, its 7-hydroxylated metabolites, and in the first case also dehydroepiandrosterone sulphate (DHEAS), were measured before, during and one day after the end of treatment. Application of DHEA increased significantly not only DHEA and DHEAS, but also its both 7-hydroxyisomers. Application of 7-oxo-DHEA also led to a significant increase of both 7-hydroxyisomers of DHEA, with 7beta-OH-DHEA being the preferred metabolite the concentration of which was increased more than three times.

Administration, Cutaneous↗

PubMed2000

Minireview: 16alpha-hydroxylated metabolites of dehydroepiandrosterone and their biological significance.

16alpha-Hydroxydehydroepiandrosterone is the precursor of fetal 16alpha-hydroxylated estrogens, the main phenolic steroids in pregnancy. For years their serum levels have been used as biochemical markers of well being of the fetus. In adults, however, increased levels of 16-hydroxylated estrogens were put in relation to the risk of cancer and, more recently, to some systemic autoimmune diseases. With respect to immunomodulatory effect of dehydroepiandrosterone and its metabolites, of which 7-hydroxysteroids formed by a concurrent reaction to 16-hydroxylation, are believed to be even the more immunoprotective species, it may be of interest, what is the true role of 16alpha-hydroxydehydroepiandrosterone and other 16-hydroxysteroids of 3beta-hydroxy-5-ene series. The present knowledge on the latter metabolite was summarized and discussed.

Autoimmune Diseases↗

PubMed2000

Effects of transdermal application of DHEA on the levels of steroids, gonadotropins and lipids in men.

In order to ascertain the kinetics of absorption and metabolism of transdermally administered dehydroepiandrosterone (DHEA), 10 men 29-72 years old (mean 52.4+/-14.5) received 50 mg DHEA/day in a gel applied onto the skin of the abdomen for 5 consecutive days. The objective was to establish the extent to which DHEA influences the levels of gonadotropins, sex hormone-binding globulin and lipids. It was found that DHEA is well absorbed and rapidly metabolized to its sulfate (DHEAS), androstenedione, and consequently to testosterone and estradiol. The DHEA levels that markedly increased after the first doses gradually declined already during the application, and this decline proceeded even after it was discontinued, reaching levels significantly lower than the original ones. On the other hand, the levels of DHEA metabolites (with the exception of DHEAS) rose during the application and reached values significantly higher than the basal ones within 5 weeks. This effect was accompanied by significantly decreased levels of LH. The serum levels of lipids, namely of cholesterol (both HDL and LDL cholesterol), triglycerides, apolipoproteins A-I and B and lipoprotein(a) after DHEA application were not changed significantly, and the atherogenic index (AI) remained unaltered. However, some correlations between hormones and lipids were found. Negative correlations concerned the following indices: DHEA/Lp(a); DHEAS/cholesterol; DHEA, DHEAS, testosterone/TG; testosterone/AI. On the other hand, LH, FSH/cholesterol, FSH, SHBG/LDL cholesterol, FSH/Apo B, Lp(a) correlated positively. It can be concluded that transdermal short-time application of DHEA results in a decrease of endogenous DHEA after finishing the treatment, with a parallel marked increase in the levels of sex hormones. Using this application protocol, exogenous DHEA neither altered the lipid spectrum, nor did it influence the atherogenic index.

Administration, Cutaneous↗

PubMed2000

[Selected phytoestrogens with potential beneficial effects on risk of certain environmental diseases].

Evidence has been accumulated that some phytoestrogens act as protective factors against development of cancer and also cardiovascular diseases. These are phytoestrogens of isoflavone and lignane series, found especially in soy. Beneficial effect of these compounds may be explained by a complexity of their actions at various levels: they interact with estrogen receptors, some of them are inhibitors of the key enzymes responsible in the final effect for cell growth and proliferation, and, due to their chemical nature they are scavengers of free radicals. In the presented work the authors, in collaboration with Finnish partners from the University of Helsinki, developed original immunoassays for determination of main phytoestrogens of isoflavone series--daidzein, genistein, formononoetin, biochanin A, their metabolite equal and lignane enterolactone. The methods are sensitive enough for follow-up of actual levels of phytoestrogens in serum. By using these methods, the levels of phytoestrogens in Czech population have been established. The group of patients suffering from osteoporosis has been investigated, too. Significantly lower levels of isoflavonoids in comparison with sex- and age-matched healthy subject have been found in the patients. The methods have also enabled us to follow up the dynamics of these compounds in the organism, as well as to determine their content in food and its sources. The original detection and quantification of four above mentioned isoflavonoids in beer is an example.

Anticarcinogenic Agents↗

PubMed1999

Immunoassay of 7-hydroxysteroids: 2. Radioimmunoassay of 7alpha-hydroxy-dehydroepiandrosterone.

High sensitivity radioimmunoassay of 3beta, 7alpha-dihydroxy-5-androsten-17-one (7alpha-OH-DHEA) has been developed and evaluated. The method is based on polyclonal rabbit antisera raised against 19-O-(carboxymethyl)oxime bovine serum albumin conjugate and bridge- and position homologous [(125)I]iodotyrosine methyl ester as a tracer. Sensitivity of the assay amounted to 3.12 fmol (0.95 pg)/tube, precision as a mean intra- and interassay coefficient of variation was 7.1 and 10.6%, respectively, and the average recovery of the analyte added to steroid-free serum was 110%. Out of the steroids occurring in human serum which may interfere with the assay, the only important cross-reactants were dehydroepiandrosterone and 3beta, 7beta-dihydroxy-5-androsten-17-one (7beta-OH-DHEA) with cross-reactivities of 1.95 and 1.16%, respectively. The levels of free (unconjugated) 7alpha-OH-DHEA have been determined in 29 sera from healthy volunteers (23 females and 6 males), and from 48 patients (43 females and 5 males) in which dehydroepiandrosterone and its sulfate (DHEA/S) had been measured for various endocrinopathies. The levels in healthy subjects ranged from 0.21 to 6.57 (mean 2.33+/-1.50) nM, while those of the patients from 0 to 5. 99 (mean 1.46+/-1.52) nM. The levels of 7alpha-OH-DHEA in patients significantly correlated with those of DHEA and its sulfate.

Animals↗

PubMed1999

7Beta-OH-DHEA counteracts dexamethasone induced suppression of primary immune response in murine spleenocytes.

The effect of dexamethasone and of three potential antiglucocorticoids, namely dehydroepiandrosterone (DHEA) and its 7alpha-and 7beta-hydroxylated metabolites, on primary immune response has been studied by measuring the number of plaque forming cells (NPFC) and their viability in a cell culture of murine spleenocytes. As expected, dexamethasone suppressed considerably the NPFC as well as their viability. Surprisingly, DHEA as well as its 7alpha-hydroxylated metabolite decreased significantly the NPFC, while the effect of 7beta-hydroxy-DHEA was different: at low doses it decreased the NPFC, but this effect was less pronounced at higher concentrations. In addition, 7beta-hydroxy-DHEA was able to counteract the effect of dexamethasone on the NPFC. None of the natural steroids affected the cell viability.

Animals↗

PubMed1999

[Prevalence of genetic variants of luteinizing hormone in the Czech Republic].

BACKGROUND: The relatively common genetic variant of LH beta-subunit, resulting in changes of the pituitary-gonadal axis, displays different prevalence in various ethnic populations. METHODS AND RESULTS: Frequency of occurrence of the variant allele in our country has been determined by analysis of LH in a randomly selected population group from the Cheb region, comprising of 257 subjects (82 men and 175 women) in the age from 14 to 72 years. The LH variant was determined by a novel immunofluorescence method, based on two assays, of which the first detected the wild type of the hormone and its variant, while the second was specific for the wild type of LH only. The frequency of carriers of the variant allele for LH-beta-subunit amounted to 17.5%, i.e. 12.2% in males and 20.6% in females. CONCLUSIONS: The prevalence of the variant allele for LH-beta-subunit in the investigated region of West Bohemia was close to that of other Antral European and North European populations.

Adolescent↗

PubMed1999

Elimination of cross-reactivity by addition of an excess of cross-reactant for radioimmunoassay of 17alpha-hydroxypregnenolone.

Polyclonal antiserum against 3beta,17alpha-dihydroxypregn-5-en-20-one-19-O-(carboxymethyl )-oxime bovine serum albumin (17alpha-hydroxypregnenolone-19-CMO:BSA), was raised in rabbits. Its main structural determinants were the substituents on D-ring as demonstrated by its 107% cross-reaction with 17alpha-hydroxyprogesterone. This unspecificity was almost completely eliminated by addition of the excess of the cross-reactant directly to the analytical system. The contribution of the cross-reactant from the sample in such a system became negligible due to saturation of the populations of polyclonal antibodies recognizing the analyte as well as the cross-reactant. The possible interference of 17alpha-hydroxypregnenolone-3-sulfate was avoided by inserting ether extraction. The analytical system appeared to be stable to differences in cross-reactant concentrations even in samples from patients with pathologically elevated serum levels of 17alpha-hydroxyprogesterone. The radioimmunoassay was compared with the system using the unspecific antiserum alone, but after separation of the cross-reactants by HPLC. As demonstrated by parallel measurement of 125 samples of human plasma from both sexes and various ages either before and/or after adrenocorticotropin stimulation and 17 samples with elevated basal of human plasma 17alpha-hydroxyprogesterone levels, an excellent correlation was achieved between both methods. The method, based on a simple addition of the cross-reactant, avoids the time-consuming chromatographic separation and, in comparison with the other approaches for improving the specificity of polyclonal antisera, is efficient and rapid. Mathematical analysis of the relations in equilibrium demonstrates that such a simple approach is an efficient way for improvement of immunoassay specificity using some polyclonal antisera.

17-alpha-Hydroxypregnenolone↗

PubMed1999

Age relationships and sex differences in serum levels of pregnenolone and 17-hydroxypregnenolone in healthy subjects.

17-Hydroxypregnenolone (3beta,17alpha-dihydroxypregn-5-en-20-one) and pregnenolone (3beta-hydroxypregn-5-en-20-one) were determined by radioimmunoassay following HPLC separation in serum of healthy subjects of both sexes from 2 to 66 years old (29 girls, 85 women, 30 boys, 89 men). The effects of age and sex on the levels of both steroids were investigated and the upper limits of normal in age groups were determined. The 17-hydroxypregnenolone levels as a function of age were characterized by a statistically significant maximum at the age of 18 and 20 years followed by a local minimum at the age of 39 and 37 years and by a statistically insignificant local maximum at the age of 55 and 49 years in men and women, respectively. Pregnenolone age-dependence was similar and the statistically significant maximum was reached at the age of 17 and 16 years, the local minimum occurred at the age of 37 and 38 years and the second, statistically insignificant, local maximum at the age of 48 and 47 years in men and women, respectively. Both 17-hydroxypregnenolone and pregnenolone in both sexes exhibited similarly shaped peaks with age. Both peaks of the polynomial fit in 17-hydroxypregnenolone were more pronounced in men than in women (13.0 and 9.20 nmol/l in the first peak; 7.72 and 4.78 in the second peak respectively). The situation with pregnenolone was the opposite. Both peaks of the polynomial fit in pregnenolone were lower in men than in women (2.29 and 3.21 nmol/l in the first peak; 0.92 and 1.78 in the second peak, respectively). The higher serum levels of pregnenolone at puberty and during fertile age and their wider variance in comparison with men could, be explained by the different gonadal steroidogenesis depending on the menstrual cycle, where the pregnenolone serves as a substrate for progesterone formation. The age dependencies of 17-hydroxypregnenolone and pregnenolone in women resembled that of unconjugated dehydroepiandrosterone. These results indicate that the increased metabolic activity in gonads in adolescence concerns not only dehydroepiandrosterone as the product of the 5-ene metabolic pathway but also its precursors.

17-alpha-Hydroxypregnenolone↗

PubMed1999

Genetic variant of luteinizing hormone in Czech Republic.

OBJECTIVE: To evaluate the frequency of luteinizing hormone (LH) variant in males and females in West region of the Czech Republic. This species of mutated LH concerns borderline alterations in pituitary-gonadal function, including higher risk for the development of more aggressive forms of prostate carcinoma in males. METHODS: The examined normal population consisted of randomly selected 82 males and 175 females (age range of 14 to 72 years). Variant LH was determined by immunofluorimetric method using two pairs of monoclonal antibodies, one of which detecting both wild-type (w+) and variant LH, while the other detecting only w+-LH. RESULTS: The carrier frequency of the variant LH allele in the population sample was 17.5 % (12.2 % in males and 20.6 % in females) which was within the range of the European prevalence. CONCLUSION: The prevalence of the common variant of LH in the investigated region of West Bohemia was close to that of other Middle-European and North-European populations.

Adolescent↗

PubMed1998

Time-resolved fluoroimmunoassay for plasma enterolactone.

We present a method for the determination of the lignan enterolactone in plasma (serum). This compound, produced by intestinal bacteria from matairesinol and secoisolariciresinol in fiber-rich food, is a biomarker related to the intake of a healthy diet. The method is based on time-resolved fluoroimmunoassay using a europium chelate as a label. After synthesis of 5'-O-carboxymethoxyenterolactone the compound is coupled to bovine serum albumin and then used as antigen in immunization of rabbits. The tracer with the europium chelate is synthesized using the same 5'-derivative of enterolactone. After enzymatic hydrolysis and ether extraction the immunoassay is carried out using the VICTOR 1420 multilabel counter (Wallac Oy, Turku, Finland). No antiserum cross-reactivity with available lignans, isoflavonoids, or flavonoids could be detected. The intraassay and interassay coefficients of variation at different concentrations vary 4.6-6.0 and 5.5-9.9, respectively. The working range of the assay is 1.5-540 nmol/liter. We measured enterolactone in serum/plasma of 224 Finnish subjects: 98.8% of the subjects had values <100 nmol/liter, 38.0% had 20-39.9 nmol/liter, and 34.4% had <20 nmol/liter.

4-Butyrolactone↗

PubMed1998

[Dehydroepiandrosterone, "the youth hormone", in the light of recent findings].

A number of beneficial effects consisting in suppression or at least diminishing of degenerative changes associated with aging is ascribed to dehydroepiandrosterone (3 beta-hydroxy-5-androsten-17-one, DHEA) and its sulfate (DHEAS), in spite of the fact that it does not act as other hormonal steroids through its specific intracellular receptors. The typical feature of DHEA is the decline of its levels with age. Apart from the fact that DHEA functions as a precursor of biologically active androgens and estrogens, the beneficial effects associated with this steroid may be characterized as anticancerogenic, antisclerotic, antidiabetic, antiobese and immunostimulatory or immunoprotective ones. A specific chapter represent its effects in brain, where DHEA acts as one of neurosteroids in a non-genomic way. In this mini-review we have focused especially on immunostimulatory and immunoprotective effects of DHEA(S), many of which but not all, may be explained by antiglucocorticoid effects of DHEA at various levels. We have attempted to outline at which sites and levels DHEA may act in the ligh of recent knowledge on the mechanism of glucocorticoid action. Finally, the results of the recent studies are surveyed, indicating that not only DHEA itself, but some of its metabolites, namely its 7-hydroxylated derivatives, may act as locally active antiglucocorticoids.

Aging↗

PubMed1998

Identification of isoflavonoids in beer.

The isoflavonoids, genistein (4',5,7-trihydroxyisoflavone), biochanin A (5,7-dihydroxy-4'-methoxyisoflavone), daidzein (4',7-dihydroxyisoflavone), and formononetin (7-hydroxy-4'-methoxyisoflavone) are supposed to be health-promoting dietary factors of plant origin. They are particularly abundant in seeds and other parts of many plant species belonging to Leguminosae. The most popular source of isoflavonoids in human diet is soy. Here, evidence is presented that isoflavonoids are regularly found in beer. Diethyl ether extracts of beer were fractionated on thin-layer chromatography-silica, (straight phase) and rechromatographed using a reversed phase high-performance liquid chromatography octadecylsilica column. The fractions were analyzed by two recently developed radioimmunoassays, the first of them being specific for diadzein/formononetin and the second one specific for genistein/biochanin A. The immunoreactivity was found only in fractions with the mobility corresponding to the positions of standards on control chromatograms. Additionally, 26 samples of bottled beer were analyzed for isoflavonoid content using the combination of reversed phase high-performance liquid chromatography and radioimmunoassay. The sum of the four isoflavonoids ranged from 1.26 to 29 nmol/L in individual beers. Formononetin was the major isoflavonoid (0.19-14.99 nmol/L), whereas the concentration of daidzein was several times lower (0.08-2.5 nmol/L). Genistein and biochanin A concentrations were comparable, ranging from 0.169-6.74 nmol/L and from 0.820-4.84 nmol/L for genistein and biochanin A, respectively. It is concluded that beer contains significant amounts of biologically active isoflavonoid phytoestrogens.

Beer↗