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Start Over Creator Stárka, L.

1. 7 - Hydroxydehydroepiandrosterone - a Natural Antiglucocorticoid and a Candidate for Steroid Replacement Therapy?

Creator:
Hampl, R., Lapčík, O., Hill, M., Klak, J. , Kasal, A., Nováček, A. , Šterzl, I., Šterzl, J., and Stárka, L.
Type:
article, model:article, and TEXT
Subject:
Dehydroepiandrosterone, 7-Hydroxydehydroepiandrosterone, Antiglucocorticoid, Immunoprotection, and Hormone replacement
Language:
English
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. A method for determination of one hundred endogenous steroids in human serum by gas chromatography-tandem mass spectrometry

Creator:
Hill, M. , Hána, V. , Velíková, M., Pařízek, A., Kolátorová, L. , Vítků, J., Škodová, T., Šimková, M. , Šimják, P. , Kancheva, R., Koucký, M. , Kokrdová, Z., Adamcová, K. , Černý, A. , Hájek, Z., Dušková, M., Bulant, J., and Stárka, L.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Steroid metabolome, Human blood, Gas chromatographytandem mass spectrometry, Backdoor pathway, Pregnancy, and Mixed umbilical cord blood
Language:
English
Description:
Steroid profiling helps various pathologies to be rapidly diagnosed. Results from analyses investigating steroidogenic pathways may be used as a tool for uncovering pathology causations and proposals of new therapeutic approaches. The purpose of this study was to address still underutilized application of the advanced GC-MS/MS platform for the multicomponent quantification of endogenous steroids. We developed and validated a GC-MS/MS method for the quantification of 58 unconjugated steroids and 42 polar conjugates of steroids (after hydrolysis) in human blood. The present method was validated not only for blood of men and non-pregnant women but also for blood of pregnant women and for mixed umbilical cord blood. The spectrum of analytes includes common hormones operating via nuclear receptors as well as other bioactive substances like immunomodulatory and neuroactive steroids. Our present results are comparable with those from our previously published GC-MS method as well as the results of others. The present method was extended for corticoids and 17α-hydroxylated 5α/β-reduced pregnanes, which are useful for the investigation of alternative “backdoor” pathway. When comparing the analytical characteristics of the present and previous method, the first exhibit by far higher selectivity, and generally higher sensitivity and better precision particularly for 17α-hydroxysteroids.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

3. Circulating Neuroactive C21- and C19-Steroids in Young Men Before and After Ejaculation

Creator:
Stárka, L., Hill, M., Havlíková, H., Kancheva, L., and Sobotka, V.
Type:
article, model:article, and TEXT
Subject:
Allopregnanolone, Ejaculation, 17a-hydroxypregnenolone, Neuroactive steroids, and Testosterone
Language:
English
Description:
Twelve neuroactive and neuroprotective steroids, androgens and androgen precursors i.e. 3a,17b-dihydroxy-5a-androstane, 3a-hydroxy-5a-androstan-17-one, 3a-hydroxy-5b-androstan-17-one, androst-5-ene-3b,17b-diol, 3b,17a-dihydroxy-pregn-5-en-20-one (17a-hydroxy-pregnenolone), 3b-hydroxy-androst-5-en-17-one (dehydroepiandrosterone, DHEA), testosterone, androst-4-ene-3,17-dione (androstenedione), 3a-hydroxy-5a-pregnan-20-one (allopregnanolone), 3b-hydroxy-pregn-5-en-20-one (pregnenolone), 7a-hydroxy-DHEA, and 7b-hydroxy-DHEA were measured using the GC-MS system in young men before and after ejaculation provoked by masturbation. The circulating level of 17a-hydroxypregnenolone increased significantly, whereas the levels of other circulating steroids did not change at all. This fact speaks against the hypothesis that a decrease in the level of neuroactive steroids, e.g. allopregnanolone, may trigger the orgasm-related increase of oxytocin as it was reported by other authors.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6. Steroids and Thermogenesis

Creator:
Hampl, R., Stárka, L., and Janský, L.
Type:
article, model:article, and TEXT
Subject:
Steroids, Thyroid hormones, Thermogenesis, and Uncoupling proteins
Language:
English
Description:
Apart from thyroid hormones, as the main hormonal regulators of obligatory thermogenesis, and catecholamines, as major hormonal regulators of facultative thermogenesis, production of heat in homeotherms can also be influenced by steroids. Generally, hormones can influence heat production by regulating the activity of various enzymes of oxidative metabolism, by modulating membrane protein carriers and other membrane or nuclear protein factors. Proton carriers in the inner mitochondrial membrane, known as uncoupling proteins, play the key role in heat dissipation to the detriment of the formation of energy-rich phosphates. In this minireview we have focused on the effects of steroids and thyroid hormones on heat production in brown adipose tissues and in skeletal muscles, with particular respect to their effect on uncoupling protein expression. Apart from hormonal steroids, dehydroepiandrosterone, an important precursor in the metabolic pathway leading to hormonal steroids which possess many, mostly beneficial effects on human health, modulates metabolic pathways which may lead to increased heat production. Recent studies demonstrate that 7-oxo-dehydroepiandrosterone, one of its 7-oxygenated metabolites, is even more effective than dehydroepiandrosterone. Recent findings of various actions of these steroids support the view that they may also participate in modulating thermogenic effects.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

7. The computer modelling of human TRH receptor, TRH and TRH-like peptides

Creator:
Bílek, R. and Stárka, L.
Type:
article, model:article, and TEXT
Subject:
Throtropin-releasing hormone receptor, TRH, TRH-like peptides, and Computer modeling
Language:
English
Description:
The aim of this work was to verify the possibility of interactions between the human TRH receptor (an integral membrane protein which belongs to family 1 of G-protein coupled receptors) and TRH-like peptides presented in the prostate gland. These peptides are char acterized by substitution of basic amino acid histidine (related to authentic TRH) for neutral or acidic amino acid, such as glutamic acid, phenylalanine, glutamine or tyrosine. The physiological function of TRH-like peptides in peripheral tissues is not precisely known. However, according to our recent experiments, we assume the existence of a local hormona l network formed by TRH-like peptides and TSH in the prostate gland. The network can be associated with circulating thyroid and steroid hormones, and may represent a new regulatory mechanism influencing the proliferative ability of prostatic tissue. A similar network of authentic TRH and TSH was already found in the gastrointestinal tract. The experimentally determined 3D-structures of human TRH receptor (hTRHr) and TRH-like peptides are not available. From this point of view we used de novo modeling procedures of G-protein coupled receptors on an automated protein modeling server used at the Glaxo Wellcome Experimental Research (Geneva, Switzerland). 3D-s tructures of TRH-like peptides were determined with a computer program CORINA (written by the team of J. Gasteiger, Computer-Chemie-Centrum and Institute for Organic Chemistry, University of Erlangen-Nurenberg, Germany). The generated PDB files with 3D-coordinates were visualized with Swiss-Pdb Viewer Release 3.51 (Glaxo Wellcome). From recent results it is evident that polar amino acids belonging to the extracellular terminus of hTRHr transmembrane regions can participate in interactions between TRH and hTRHr. There is no direct evidence that TRH-like peptides interact with the presented hTRHr model. On the contrary, with respect to the similar 3D-shape and the identity of terminal amino acids, it appears that these interactions are highly probable as well as the nearly 100 % cross-reactions between TRH or TRH-like peptides and antibody specific against authentic TRH. Closed terminal amino acids (pyroglutamic acid and proline-amide) of TRH or TRH-like peptides are important for these interactions. Desamido-TRH or glutamyl metabolites will be repelled by the negative potential of ASP195 (E: D93) and GLU298 (G: E137).
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

8. What May Be the Markers of the Male Equivalent of Polycystic Ovary Syndrome?

Creator:
Dušková, M., Čermáková, I., Hill, M., M., Šámalíková, P., and Stárka, L.
Type:
article, model:article, and TEXT
Subject:
Premature androgenic alopecia, Polycystic ovary syndrome, SHBG, Insulin tolerance, and Male phenotype of PCOS
Language:
English
Description:
Polycystic ovary syndrome (PCOS), the most common endocrinopathy in women (with a prevalence of 5-10 %), is characterized by hormonal and metabolic imbalance. Complexity of symptoms of close relatives of women with PCOS and genetic autosomal trait initiated a hypothesis about the existence of a male equivalent of PCOS. Premature alopecia was suggested as one of the signs of a male phenotype of this syndrome. The present study investigated a group of 30 men, in which premature hair loss started before 30 years of age. In all patients, their hormonal profile was determined. It was possible to form two subgroups. The first one showed similar hormonal changes as women with PCOS, the other had either no anomalies in steroid spectrum or just only lower level of sexual hormones binding globulin (SHBG). Both subgroups did not differ in either BMI or age. In all men with premature alopecia insulin tolerance test was also carried out and the occurrence of allele 3 INS VNTR was investigated, which is one of the candidate genes for PCOS. The subgroup with hormonal changes resembling those of women with PCOS showed a significantly higher insulin resistance than the group without these changes. About one third of the premature balding men showed the combination of hormonal shifts and higher insulin resistance. This frequency corresponds to the prevalence of PCOS in women. There was no significant difference between the two subgroups in the occurrence of allele 3 INS VNTR.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public