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Biomedical subjects

R Hampl

Publications and source records attributed to R Hampl.

At least 73 records · Page 4Linked to original sources
PubMed1995

A novel radioimmunoassay of allopregnanolone.

A radioimmunoassay for determination of 3 alpha-hydroxy-5 alpha-pregnan-20-one (allopregnanolone) in serum or plasma has been developed and evaluated. The method employs rabbit antiserum to 3 alpha-hydroxy-5 alpha-pregnane-11,20-dione-11-O-carboxymethyloxime bovine serum-albumin conjugate and tritiated radioligand. The main cross-reactant interfering in the assay, progesterone, is eliminated by permanganate oxidation. Two assay variants were compared, with and without a micro-column chromatography. The simplified variant appeared to be reliable enough for determination of allopregnanolone in normally menstruating women at luteal phase, whereas the column-chromatography step is necessary when analyzing samples of expected low analyte concentration as in women in follicular phase, postmenopausal women, or in men. The levels of allopregnanolone in healthy women correlated excellently with progesterone in agreement with previous findings.

Antibody Specificity↗
PubMed1995

Radioimmunoassay of three deoxycorticoids in human plasma following HPLC separation.

A radioimmunoassay of three deoxycorticoids, namely 11 beta,17 alpha-dihydroxy-4-pregnene-3,20-dione (21-deoxycortisol), 17 alpha,21-dihydroxy-4-pregnene-3,20-dione (11-deoxycortisol), and 21-hydroxy-4-pregnene-3,20-dione (11-deoxycorticosterone) which are important for differential diagnosis of congenital adrenal disorders, is described and evaluated. Antisera against 3-(O-carboxymethyl)oximes conjugated to bovine serum albumin were raised in rabbits. The radioligands were prepared by radioiodination of previously synthesized homologous tyrosine methyl ester derivatives. Following diethyl ether extraction, the steroids were separated from each other and from cross-reactants by HPLC using a Nucleosil C8 reverse-phase column and a methanol-water mixture (7:5, v/v) as an eluent. Normal levels of analyzed steroids ranged from 0.02 to 0.348, 0.185 to 3.80, and 0.013 to 0.299 nmol/l, for 21-deoxycortisol, 11-deoxycortisol and 11-deoxycorticosterone, respectively. The levels of both deoxycortisols rose significantly after ACTH treatment. Data are given with respect to the concentrations of these steroids in some pathological situations such as 21-hydroxylase and 11 beta-hydroxylase block, hyperaldosteronism, and polycystic ovary syndrome.

Adolescent↗
PubMed1995

Plasma levels of epitestosterone from prepuberty to adult life.

Epitestosterone has for a long time been considered as a biologically inactive steroid. However, recently a distinct antiandrogenic activity of this naturally occurring endogenous epimer of testosterone has been demonstrated. Epitestosterone plays a role in the control of doping with testosterone, since an arbitrary ratio of testosterone to epitestosterone in urine has been accepted as a marker for testosterone abuse. For this reason, its urinary excretion has been examined intensively by several authors. On the other hand, its concentration in the blood of men was reported only randomly in a few cases. In the present study the epitestosterone level in human plasma was determined by a specific radioimmunoassay and the concentration of epitestosterone was established in age groups of males of 6 to 65 years of age. There is a clear age dependence of epitestosterone plasma concentration in males. In young boys before puberty, antiandrogenic epitestosterone prevails over testosterone, in adults a striking decline of the ratio epitestosterone:testosterone can be observed.

Adolescent↗
PubMed1995

The effect of epitestosterone on spermatogenesis in rats.

The effect of 3-week treatment with increasing doses of endogenous steroid with antiandrogenic properties, epitestosterone (ET), on the spermatogenesis was studied in adult male rats by flow cytometry and correlated with the effect on gonadotropin gene expression and secretion, on testosterone and dihydrotestosterone plasma levels and on the weight of testes and prostates. Epitestosterone was administered to the rats by means of silastic capsules of different lengths filled with the steroid. A decrease of the number of total spermatides in the epitestosterone treated animals was observed. In the group with the lowest dose of ET the number of elongated spermatides was significantly reduced. The number of germ cell types and their relative proportions were correlated with the endocrine parameters reported previously. Significant negative correlation between the pituitary content of LH and total number of germ cells per 1 g of testicular tissue and of the number of spermatides/g and between testosterone level in serum and the number of diploid cells in the animals treated with higher doses of ET was found. In the group with highest ET dose a negative correlation of diploid cells and serum dihydrotestosterone was observed, too. The naturally occurring antiandrogen epitestosterone can be considered as one of the endogenous factors influencing spermatogenesis.

Journal Article↗
PubMed1995

[Steroidal sex hormones and insensitivity syndromes].

BACKGROUND: Today more than one hundred mutations are known of the gene for androgen receptor (AR) and merely one mutation of that for estrogen. The current trend in research has included the completion of the list of receptor defects and seeking the coincidence with their variable clinical manifestations. AIM: The aim of the study is to review the current state of the research on the defects of androgen and estrogen receptors and to draw attention to the clinical manifestations of the resistance to the sexual steroid hormones and currently to present own contributions in this problem. METHODS: Diagnostic application of the androgen resistance dynamic test residing in investigation of the SHBG level after androgen or anabolics administration. Molecular-biological analysis of AR defects with Phe 878 Ser mutation. CONCLUSIONS: Perspective acknowledgement of androgen and estrogen receptor defects allows a more precise diagnosis statement and perhaps also therapy of various forms of resistance to steroid sexual hormones. It can contribute to the understanding of some subsequent pathological processes dependent on the expression of androgens and estrogens. (Tab. 1, Ref. 20.).

Disorders of Sex Development↗
PubMed1994

[Androgen insensitivity].

Manifestations of resistance to androgens vary within a wide range from an almost normal female phenotype to men whose only complaint is infertility. Insensitivity is caused by mutation of the gene for androgenic receptors, located on the X chromosome. Androgenic insensitivity is associated of all known hormonal resistances with the most varied mutational changes-some hundred of the latter were described. Mutations do not correlate with the clinical picture. Insensitivity to androgens is not necessarily associated with the inability of androgens to bind with the appropriate receptor, because mutations can affect any of the three receptor domains, i.e. not only the domain binding the ligand but also the domain by which the steroid receptor complex is linked to the DNA of the regulated gene or N-terminal, the so-called transactivation domain, responsible for the transfer of the hormone-borne signal to the initiation site of the controlled gene. Androgenic insensitivity can be associated with some tumourous diseases depending on steroid sex hormones such as prostate or breast cancer and also-as reported for the first time in this paper-e.g. with lymphogranuloma. Some neurodegerative diseases are also associated with a certain degree of androgenic insensitivity. For detection of androgenic resistance in addition to molecular genetic analysis dynamic tests were recommended which involve the follow-up of androgen-dependent indicators after androgen administration. These indicators are e.g. nitrogen retention or the SHBG level. The original modification of the SHBG test for androgen insensitivity is described.

Androgen-Insensitivity Syndrome↗
PubMed1994

The effect of long-term glucocorticoid therapy on glucocorticoid receptor content and on steroid response to ACTH.

The effect of long-term glucocorticoid therapy for systemic diseases on glucocorticoid receptor (GR) content and on basal and ACTH-stimulated levels of plasma and salivary cortisol 17 alpha-hydroxy-progesterone, androstenedione, 11 beta-hydroxyandrostenedione, DHEA, its sulfate and sex hormone-binding globulin (SHBG), as well as on basal levels of aldosterone, was investigated in a group of 24 children treated with prednisone for at least 8 months. The therapy was interrupted 24 h before the ACTH test and before plasma and saliva sampling. The control group consisted of 21 healthy children of corresponding age and sex. The patients were divided into two subgroups with normal and subnormal basal cortisolemia, they also differed in their response to ACTH. The GR levels in patient groups were indistinguishable from those found in controls. No correlation was found between GR content and basal levels of the above steroids or their response to ACTH. The best markers, apart from basal cortisolemia, for evaluation of the degree of suppression of adrenal function appeared to be the response of salivary (but not of plasma) cortisol and 17 alpha-hydroxy-progesterone to ACTH. Surprisingly, significantly lower levels of SHBG levels, which rose markedly after ACTH, were found in all the patients.

Adolescent↗
PubMed1994

The effect of epitestosterone on gonadotrophin synthesis and secretion.

The effects of 3-week treatment with increasing doses of epitestosterone (ET) on gonadotrophin gene expression and secretion, on testosterone and 5 alpha-dihydrotestosterone (DHT) levels, and on the weight of testes and prostates, were studied in intact adult male rats. The hormones were delivered by means of silastic capsules of different lengths filled with the steroid. One group of rats received testosterone (T) instead of ET, to compare the results with previous studies concerning the testosterone effect. The controls were given capsules with glucose only. Treatment with ET, as well as with T, significantly reduced the weights of prostates. When the data from ET-treated rats and controls were combined, a significant negative correlation (P < 0.001) was found between the weight of prostates and serum ET. T, in contrast to ET, also decreased significantly the weights of testes, ET treatment caused a significant reduction of serum T levels but only an insignificant decline of DHT levels, independent of the dose. Serum and pituitary (p) luteinizing hormone (LH) levels in the ET-treated rats did not change. Pituitary mRNA contents for the beta LH subunit (beta LH-mRNA) showed a dose-dependent significant increase, up to 170% (P < 0.01), with ET treatment. pFSH decreased with the lowest ET (2 cm) dose (P < 0.05), but no change was observed with the other doses. The mRNA for the common alpha-subunit also increased with the ET load. In conclusion, ET acts at several sites in the regulation of gonadotrophin formation and release. It enhances the steady-state mRNA levels of both gonadotrophins in the pituitary.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

The activity of epitestosterone in hormone dependent prostate tumour models.

Epitestosterone has been shown previously to counteract the testosterone activity in some experimental models. In the present study the activity of epitestosterone in an in vitro model of human LNCaP/FCS prostate cells and in vitro in Dunning R 3327-GH rat prostate carcinoma was tested. In LNCaP/FGC cells cultivated with fetal calf serum (FCS) treated with dextran-coated charcoal epitestosterone displayed rather androgenic than antiandrogenic properties, whereas the cultivation with native FCS resulted in a very weak inhibition of tumour cell growth with epitestosterone in higher concentration. The growth of Dunning R 3327-GH carcinoma of prostate was very weakly enhanced by epitestosterone alone as late as at the end of the 5-week experiment. Epitestosterone did not significantly inhibit the testosterone stimulated tumour growth.

Adenocarcinoma↗
PubMed1993

Inhibition of steroid 17 alpha-hydroxylase and C17,20-lyase in the human testis by epitestosterone.

Epitestosterone (17 alpha-hydroxy-4-androsten-3-one) inhibited competitively 17 alpha-hydroxylation of pregnenolone and subsequent C17,20-side chain cleavage of resulting 17 alpha-hydroxypregnenolone using microsomal preparations from the human testis. The inhibition constants for 17 alpha-hydroxylase and C17,20-lyase with 5-ene-precursors of C21-steroids were 96 and 12.4 mumol/l, respectively.

Aldehyde-Lyases↗
PubMed1993

Evaluation of SHBG test for disclosure of insensitivity to androgens.

A laboratory test enabling to reveal and confirm the suspicion on the insensitivity to androgens was evaluated. The test consisted of determination of the decline in plasma level of sex hormone binding globulin (SHBG) on the 7th day after administration of a single dose of testosterone preparation (Testoviron Depot 100, Schering, 2 mg/kg body weight). The upper limit of percentual SHBG decline, below which the patients can be considered normal responders (i.e. subjects without insensitivity to androgens), obtained from the follow up of the time course of SHBG changes after Testoviron application to 6 healthy men, was established as 83.6%. The level of percentual SHBG decline, above which the patients were considered non-responders with impaired peripheral sensitivity to androgens was assessed from the imprecision of immunoradiometric determination of SHBG and amounted 91.9%. The test was used and evaluated in 26 patients with 46 XY karyotype, representing various cases of intersex, gonadal dysgenesis and male hypogonadism, out of which four subjects with clinically confirmed impaired peripheral sensitivity to androgens were discovered. The test however, appeared not to be reliable in cases of very low basal SHBG levels, i.e. below 15 nmol/l.

Adolescent↗
PubMed1992

Antihormonal properties of some new A-homo-B, 19-dinor steroids of the androstane series.

On solvolysis of Westphalen-type steroids with a leaving group in the position 6 beta (e.g., 2), products of elimination (followed by rearrangement and fragmentation of the steroid skeleton) were prepared (e.g., 4 and 5). These products were subsequently converted to suitable analogs of the compound, which has been reported to promote hair growth (1). Compounds 11 to 13 exhibited strong antiandrogenic activity in vivo; however, this activity could not be interpreted either in terms of inhibition of 5 alpha-reductase or by strong binding to an androgen receptor.

Androgen Antagonists↗
PubMed1992

Serum levels of steroid hormones in men with varicocele and oligospermia as compared to normozoospermic men.

In order to assess the contribution of individual steroidogenic organs to over-all steroid biosynthesis, the basal plasma levels of six hormonal steroids, reflecting the function of gonads and adrenals, as well as both gonadotropins and prolactin, have been determined in 63 oligo- and/or asthenozoospermic men with palpable varicocele, confirmed in each case by sonography. The values obtained were compared with the results of a group of age-matched normospermic men without endocrine disorders. Insignificantly lower levels of testosterone accompanied by significantly lower levels of dihydrotestosterone, slightly decreased LH but increased FSH undistinguishable concentrations of cortisol in patients with varicocele were in agreement with previous findings. Higher levels of an exclusively adrenal androgen 11 beta-hydroxyandrostenedione in men with varicocele indicate increased activity of the adrenal cortex. Significantly higher basal levels of 17 alpha-hydroxyprogesterone in the patient group (p < 0.001), so far not unequivocally proved, evidence for suggested decreased enzyme activity of C17-20 lyase in the testis in at least some of men with varicocele.

17-alpha-Hydroxyprogesterone↗
PubMed1992

[Use of modern methods in prenatal diagnosis of congenital adrenal hyperplasia--examination protocol].

The prenatal diagnosis of congenital adrenal hyperplasia (CAH) in the second trimester of gestation (as done so far in this country) is late and unsuitable with regard to possible interruption of pregnancy. Modern methods of early prenatal diagnosis are based on examination of material from chorionic villi (6th-10th week of gestation) or early amniocentesis (10th-12th week of gestation). The authors present their decision taking scheme, examination protocol and their own experience with the use of molecular genetic analysis and assessment of 17-hydroxyprogesterone from early amniocentesis in the prenatal diagnosis of CAH. This procedure is a priority in this country.

Adrenal Hyperplasia, Congenital↗
PubMed1992

Single point estimation of glucocorticoid receptors in lymphocytes of normal subjects and of children under long term glucocorticoid treatment.

A single point assay of glucocorticoid receptors (GR) in human lymphocytes based on the measurement of specific dexamethasone binding has been developed and compared with a common multi-point Scatchard analysis. The assay conditions-concentration of the ligand 20 nmol/l, incubation time 2 h and the cell count 2-6 mil. cells/tube in the assay volume 0.25 ml were found to be optimal. An attempt was also undertaken to use a cell harvester for the separation of cells from unbound ligand. Though specifically bound dexamethasone measured by whole-cell assay and that using cell harvester correlated well, almost by one order lower values obtained with the latter method render it non-applicable for receptor quantitation. The results from 9 healthy volunteers (average GR concentration 7131 +/- 1256 sites/cell) correlated excellently with those obtained by the Scatchard analysis. The single point assay has been also applied for determination of GH in 10 children treated with large doses of prednisone. The average values from healthy volunteers did not differ significantly from those found in these children, though much broader range was found in patients.

Adolescent↗
PubMed1992

[A laboratory test for the detection of androgen resistance using sex hormone-binding globulin].

A simple laboratory test for disclosure of peripheral androgen insensitivity has been suggested. The test is based on determination of sex hormone-binding globulin (SHBG) following single administration of testosterone preparation (Testoviron Depot, Schering, 2 mg/kg of body weight). The kinetics of SHBG response to exogenous testosterone was investigated first in a group of 5 healthy male volunteers. The highest highly significant decrease of SHBG level occurred 7th day after drug administration. The method of choice for SHBG determination is an immunoradiometric assay (IRMA). The test was used for a group of 15 children and young people suspected for androgen sensitivity disorder. In all cases, besides SHBG on days 0 and 7 testosterone, dihydrotestosterone and LH were measured, too. In three instances the response was negative: in the case of male Turner syndrome, with very low basal SHBG levels, in one case of confirmed diagnosis of testicular feminization and in the third case of suspected testicular feminization, which has not yet been concluded. In all other patients a significant decrease (in average to 62.8% of the basal level) was in agreement with clinical findings.

Adolescent↗
PubMed1991

[Determination of steroid hormones in the amniotic fluid in prenatal genetic diagnosis].

In amniotic fluid from the second trimester of pregnancy levels of total and free testosterone, 17 alpha-hydroxyprogesterone and dehydroepiandrosterone were assessed. The median levels of total testosterone during the 15th to 24th week are 0.82 +/- 0.31 nmol/l in pregnancies with male foetuses and 0.32 +/- 0.11 nmol/l in pregnancies with female foetuses. The levels of free testosterone assessed by calculation from concentrations of SHBG and total testosterone are 0.15 +/- 0.04 for male and 0.05 +/- 0.04 nmol/l for female foetuses. The diagnostic reliability of sex determination of the foetus from the total testosterone concentration in amniotic fluid is 94% and estimation of free testosterone increases it further. The median normal 17 alpha-hydroxyprogesterone levels during the 15th to 23rd week of pregnancy are 8.7 +/- 3.5 nmol/l and do not depend on the sex of the foetus and week of pregnancy. The levels of dehydroepiandrosterone in amniotic fluid from the second trimester of pregnancy are in male foetuses 0.64 +/- 0.33 nmol/l and 0.61 +/- 0.32 nmol/l in female foetuses and do not differ. Assessment of testosterone levels serves as a supplementary method for determination of the sex of the foetus and may play an important part in the prenatal diagnosis of syndromes with agenesis of testicles. Estimation of 17 alpha-hydroxyprogesterone is used in prenatal diagnosis of congenital adrenal hyperplasia, estimation of dehydroepiandrosterone can be used in the prenatal diagnosis of hereditary forms of adrenal hypofunction.

17-alpha-Hydroxyprogesterone↗