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Goodbye and farewell to Endocrine Connections! Endocr Connect 2021; 10:EC-21-0044. [PMID: 33512330 PMCID: PMC8052564 DOI: 10.1530/ec-21-0044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 01/28/2021] [Indexed: 12/01/2022]
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Effects of isoflavones on breast tissue and the thyroid hormone system in humans: a comprehensive safety evaluation. Arch Toxicol 2018; 92:2703-2748. [PMID: 30132047 PMCID: PMC6132702 DOI: 10.1007/s00204-018-2279-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 07/31/2018] [Indexed: 02/06/2023]
Abstract
Isoflavones are secondary plant constituents of certain foods and feeds such as soy, linseeds, and red clover. Furthermore, isoflavone-containing preparations are marketed as food supplements and so-called dietary food for special medical purposes to alleviate health complaints of peri- and postmenopausal women. Based on the bioactivity of isoflavones, especially their hormonal properties, there is an ongoing discussion regarding their potential adverse effects on human health. This review evaluates and summarises the evidence from interventional and observational studies addressing potential unintended effects of isoflavones on the female breast in healthy women as well as in breast cancer patients and on the thyroid hormone system. In addition, evidence from animal and in vitro studies considered relevant in this context was taken into account along with their strengths and limitations. Key factors influencing the biological effects of isoflavones, e.g., bioavailability, plasma and tissue concentrations, metabolism, temporality (pre- vs. postmenopausal women), and duration of isoflavone exposure, were also addressed. Final conclusions on the safety of isoflavones are guided by the aim of precautionary consumer protection.
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Thyroid hormone and its metabolites in relation to quality of life in patients treated for differentiated thyroid cancer. Clin Endocrinol (Oxf) 2016; 85:781-788. [PMID: 27175823 DOI: 10.1111/cen.13101] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/21/2016] [Accepted: 05/11/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND Levothyroxine (LT4) is the standard of care in patients with hypothyroidism. Despite this replacement therapy, quality of life (QoL) remains impaired in a substantial amount of patients. The reasons for this are still a matter of debate. Suggested causes include lack of endogenous T3 secretion by the thyroid, changes in other thyroid hormone metabolites and interference by autoimmune processes. OBJECTIVE To investigate the association between thyroid function tests (TFTs) and QoL in patients with a history of differentiated thyroid cancer on LT4 monotherapy. These patients lack endogenous thyroidal T3 secretion in the absence of autoimmune disease. MATERIALS AND METHODS This is a cross-sectional study in 143 patients (69·2% female). Initial therapy consisted of total thyroidectomy followed by radioiodine ablation minimally one year before inclusion. We assessed health-related QoL (RAND-36), thyroid-specific QoL (ThyPRO) and fatigue with the Multidimensional Fatigue Inventory. Extensive TFTs were assessed, including 3,5-diiodo-L-thyronine (3,5-T2). RESULTS Mean age was 50·2 years and mean time since diagnosis was 8·4 years. Median TSH was 0·042 mU/l, total T4 145·0 nmol/l, free T4 25·6 pmol/l, total T3 1·93 nmol/l, reverse T3 0·53 nmol/l and 3,5-T2 0·86 nmol/l. Multiple linear regression analyses did not show any association between QoL and the different TFTs, including T4/T3 and 3,5-T2/T3 ratios reflecting peripheral metabolism. CONCLUSION We did not find any association between TFTs and QoL in athyreotic patients on LT4 monotherapy. Our data do not provide evidence that a slight increase in dose improves fatigue or well-being in hypothyroid patients on LT4 therapy.
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High Variability of Insulin Sensitivity in Closely Related Obese Mouse Inbred Strains. Exp Clin Endocrinol Diabetes 2016; 124:519-528. [PMID: 27437914 DOI: 10.1055/s-0042-109261] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Obesity is one of several risk factors for insulin resistance and type 2 diabetes. Here we examined males of 6 obese mouse inbred lines derived from the Berlin Fat Mouse (BFM) outbred population with respect to insulin sensitivity and factors of the metabolic syndrome with focus on the skeletal muscle as a major target of insulin dependent glucose uptake.Males were kept on a rodent standard diet and several approaches were carried out to address insulin sensitivity, adiposity and lipids in the serum. Transcript and protein levels of several genes in the insulin signalling pathway were measured. 2 of the lines, BFMI860-12 and in particular BFMI861-S1, showed a markedly reduced insulin sensitivity already at the age of 20 weeks. BFMI861-S1 mice also displayed elevated liver triglyceride levels as a sign of lipid overload and ectopic fat storage. The analysis of the insulin signalling pathway in skeletal muscle provided evidence for low insulin receptor (INSR) and normal glucose 4 transporter (GLUT4) protein amounts in BFMI861-S1 mice, while BFMI860-12 mice showed increased INSR and very low GLUT4 protein amounts. Interestingly, the sublines BFMI860-S2 and BFMI861-S2, which are highly related to the former 2 lines, respectively, were inconspicuously insulin sensitive. The expected few genetic differences among the BFMI lines facilitate the identification of causal genetic variation. This study identified 2 mouse lines with different impairments of insulin signalling. These lines resemble useful models for studying mechanisms leading to the pathophysiology of the metabolic syndrome, in particular insulin resistance.
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Effects of repeated 3-T1AM treatment on thyrocytes in mice. Exp Clin Endocrinol Diabetes 2015. [DOI: 10.1055/s-0035-1547744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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6
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Quantitative analysis of thyroid hormone metabolites in cell culture samples using LC-MS/MS. Exp Clin Endocrinol Diabetes 2015. [DOI: 10.1055/s-0035-1547742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Influence of thyroid hormones on brown adipose tissue activity and browning of white adipose tissues in mice. Exp Clin Endocrinol Diabetes 2015. [DOI: 10.1055/s-0035-1549076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Effects of the thyroid hormone metabolite 3,5-T2 on murine heart tissue and the cardiomyocyte cell line H9C2. Exp Clin Endocrinol Diabetes 2015. [DOI: 10.1055/s-0035-1547743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Towards the intestinal biosynthesis of 3-iodothyronamine. Exp Clin Endocrinol Diabetes 2015. [DOI: 10.1055/s-0035-1547756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Phenotypic and molecular characterization of age-dependent thyroid hormone action in mice. Exp Clin Endocrinol Diabetes 2015. [DOI: 10.1055/s-0035-1547606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abnormal circulating thyroid hormone levels in MCT8-deficiency are not caused by increased hepatic conversion through type i-deiodinase. Exp Clin Endocrinol Diabetes 2015. [DOI: 10.1055/s-0035-1547759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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12
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New G protein coupled receptor targets for 3-iodotyronamine. Exp Clin Endocrinol Diabetes 2015. [DOI: 10.1055/s-0035-1547778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Establishment of a non-isotopic activity assay for thyroid hormone transporters. Exp Clin Endocrinol Diabetes 2015. [DOI: 10.1055/s-0035-1547745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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The mouse Leydig cell line MLTC-1 prefers L-thyroxine over 3,3',5-triiodo-L-thyronine in transport across plasma membrane and shows steroidogenesis response to thyroid hormone treatment. Exp Clin Endocrinol Diabetes 2014. [DOI: 10.1055/s-0034-1372318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Screening assays on inhibitors, modulators and substrates of deiodinase and dehalogenase activities. Exp Clin Endocrinol Diabetes 2014. [DOI: 10.1055/s-0034-1372314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Aspects of 3-iodothyronamine (3T1AM) induced signaling by human and mouse trace amine-associated receptor 5 (TAAR5). Exp Clin Endocrinol Diabetes 2014. [DOI: 10.1055/s-0034-1372013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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18
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Evidence for thyromimetic action of 3,5-T2 in diet-induced obese mice. Exp Clin Endocrinol Diabetes 2014. [DOI: 10.1055/s-0034-1372108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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19
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Functional and metabolic responses of thyrocytes to 3-Iodothyronamine (3-T1AM). Exp Clin Endocrinol Diabetes 2014. [DOI: 10.1055/s-0034-1372098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Pathophysiological relevance of selenium. J Endocrinol Invest 2013; 36:1-7. [PMID: 24419053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
The essential trace element selenium (Se) is a central constituent of 50-70 selenoprotein variants encoded by 25 human genes. Incorporation of the 21st proteinogenic amino acid selenocysteine occurs cotranslationally and requires peculiar features of the corresponding mRNA, a dedicated tRNA and a complex translational machinery for decoding UGA in this context. Thyroid hormone (TH) synthesis and protection of the thyroid gland from H2O2 and reactive oxygen species derived therefrom as well as TH activation and inactivation by deiodinase enzymes requires Se. Altered Se status has been associated with benign (goiter and autoimmune thyroid disease) and malignant thyroid maladies and several but not all Se supplementation studies reported on beneficial effects. Whether adequate or therapeutic Se supply is advantageous for the functional unit of the thyroid, the angiofollicular unit, or for the immune system or for both requires more controlled clinical trials and further in vitro and animal experimental studies. Development of proper diagnostic tests to monitor Se status of the thyroid gland and identification and validation of clinically useful thyroid-related biomarkers for Se action on the largest human endocrine gland are required. Several knockout and transgenic mouse models have revealed valuable insight into the role of Se and selenoprotein function for the thyroid. Recently, first human mutations in genes encoding a selenoprotein and a component involved in selenoprotein biosynthesis have been identified, the latter with marked impairment of TH homeostasis.
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Selenium in endocrinology. Foreword. J Endocrinol Invest 2013; 36:IV. [PMID: 24419058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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Strong associations of 25-hydroxyvitamin D levels with all-cause, cardiovascular, cancer and respiratory disease mortality in a large cohort study. Exp Clin Endocrinol Diabetes 2013. [DOI: 10.1055/s-0033-1336735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Thyroid hormone transporters during testicular development in rodents. Exp Clin Endocrinol Diabetes 2013. [DOI: 10.1055/s-0033-1336661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
Thyronamines (TAMs) are a newly identified class of endogenous signaling compounds. Their structure is identical to that of thyroid hormone and deiodinated thyroid hormone derivatives, except that TAMs do not possess a carboxylate group. Despite some initial publications dating back to the 1950s, TAMs did not develop into an independent area of research until 2004, when they were rediscovered as potential ligands to a class of G protein-coupled receptors called trace-amine associated receptors. Since this discovery, two representatives of TAMs, namely 3-iodothyronamine (3-T(1)AM) and thyronamine (T(0)AM), have been detected in vivo. Intraperitoneal or central injection of 3-T(1)AM or T(0)AM into mice, rats, or Djungarian hamsters caused various prompt effects, such as metabolic depression, hypothermia, negative chronotropy, negative inotropy, hyperglycemia, reduction of the respiratory quotient, ketonuria, and reduction of fat mass. Although their physiological function remains elusive, 3-T(1)AM and T(0)AM have already revealed promising therapeutic potential because they represent the only endogenous compounds inducing hypothermia as a prophylactic or acute treatment of stroke and might thus be expected to cause fewer side effects than synthetic compounds. This review article summarizes the still somewhat scattered data on TAMs obtained both recently and more than 20 yr ago to yield a complete and updated picture of the current state of TAM research.
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Abstract
Understanding of biosynthesis and metabolism of thyroid hormones have recently been substantially improved via the molecular characterization of key players like proteins essential for hormone biosynthesis, cellular thyroid hormone transporters, and intracellular enzymes involved in their activation in peripheral tissues. This improved our understanding of a number of difficult to interpret laboratory conditions. It further stimulated the development of new techniques for the future sensitive and specific measurement of a much wider than the conventional range of secretory products of the thyroid and their organ specific activation.
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Thyroid hormone deiodination in target tissues--a regulatory role for the trace element selenium? EXPERIMENTAL AND CLINICAL ENDOCRINOLOGY 2009; 102:63-89. [PMID: 8056056 DOI: 10.1055/s-0029-1211267] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The three isozymes catalyzing deiodination of thyroid hormones and iodothyronines derived thereof exert a major role in tissue- and development-specific expression of thyroid hormone action in target tissues by activating the prohormone T4 to thyromimetically active T3 or by inactivating the prohormone T4 or active T3 in non-target tissues at inappropriate time points. These three isozymes, in cooperation with the enzymes responsible for non-deiodinative degradation of iodothyronines, thus act as "guardians of the gate" to nuclear thyroid hormone receptors and other cellular target sites for thyroid hormone action. Strict and distinct hormonal, nutritional and nerval regulation of expression of the deiodinase isozymes warrants a closely coordinated control of thyroid hormone action, which directs growth, differentiation, and basal metabolic functions in the developing and the adult organism both in the periphery and in the central nervous system. The integrative action of this essential homeostatic and dynamic ancient hormone system in higher vertebrates is under the influence of two essential trace elements, iodine and selenium, which both are inadequately available for man and life stock in great parts of the world. As soon as, and only if, iodine supplementation is achieved, attempts to establish adequate selenium supply for thyroid hormone synthesis, activation, metabolism and action should be made, but not the other way around. In this review, the physiological, biochemical and pharmacological properties of the three deiodinase isozymes are discussed in detail, with special attention to the role of selenium in regulation of type I 5'-deiodinase expression. The contribution of each deiodinase izozyme to the activation and inactivation of thyroid hormones in specific tissues is reviewed.
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Redifferentiation therapy of differentiated thyroid carcinoma with retinoic acid: basics and first clinical results. Exp Clin Endocrinol Diabetes 2009; 104 Suppl 4:13-5. [PMID: 8980992 DOI: 10.1055/s-0029-1211692] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Retinoic acids (RA) regulate growth and differentiation of normal epithelial tissue. They have been employed in anticancer treatment and showed positive effects in hematopoetic and various epithelial tumors. Experimental data with follicular thyroid tumor cells showed strong evidence of induction of differentiated cell function and antiproliferative effects. Based on these data a consecutive series of 10 patients with advanced thyroid carcinoma were treated with 13-cis-retinoic acid (Roaccutan) 1.5 mg/kg body weight for six weeks. Follow-up demonstrated renewed uptake of radioiodine in 4 of 10 patients allowing performance of further radioiodine therapy. Reduction in tumor size due to antiproliferative effects of RA could not yet be verified.
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Effects of retinoids and role of retinoic acid receptors in human thyroid carcinomas and cell lines derived therefrom. Exp Clin Endocrinol Diabetes 2009; 104 Suppl 4:16-9. [PMID: 8980993 DOI: 10.1055/s-0029-1211693] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Retinoic acids (RAs), well characterized regulators of proliferation and differentiation, partly re-differentiate follicular thyroid carcinoma cell lines (FTC-133, FTC-238, and HTC-TSHr) as well as SV40-transfected immortalized thyroid cell lines (ori3 and 7751). This is indicated by the stimulation of type I 5'-deiodinase and other differentiation markers. As demonstrated by RT-PCR, electrophoretic mobility shift, and [3H]-retinoic acid binding assays, thyroid carcinoma cell lines express RA receptor mRNAs and functional ligand- and DNA-binding receptor proteins able to mediate RA-dependent signal transduction. Together, these properties make these thyroid-derived cell lines useful in vitro models for studying the effects of an RA re-differentiation therapy of thyroid cancer.
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Abstract
3-Iodothyronamine (3-T 1 AM) and thyronamine (T AM) are novel endogenous signaling molecules that exhibit great structural similarity to thyroid hormones but apparently antagonize classical thyroid hormone (T(3)) actions. Their proposed biosynthesis from thyroid hormones would require decarboxylation and more or less extensive deiodination. Deiodinases (Dio1, Dio2, and Dio3) catalyze the removal of iodine from their substrates. Because a role of deiodinases in thyronamine biosynthesis requires their ability to accept thyronamines as substrates, we investigated whether thyronamines are converted by deiodinases. Thyronamines were incubated with isozyme-specific deiodinase preparations. Deiodination products were analyzed using a newly established method applying liquid chromatography and tandem mass spectrometry (LC-MS/MS). Phenolic ring deiodinations of 3,3',5'-triiodothyronamine (rT3AM), 3',5'-diiodothyronamine (3',5'-T2AM), and 3,3'-diiodothyronamine (3,3'-T2AM) as well as tyrosyl ring deiodinations of 3,5,3'-triiodothyronamine (T3AM) and 3,5-diiodothyronamine (3,5-T2AM) were observed with Dio1. These reactions were completely inhibited by the Dio1-specific inhibitor 6n-propyl-2-thiouracil (PTU). Dio2 containing preparations also deiodinated rT(3)AM and 3',5'-T2AM at the phenolic rings but in a PTU-insensitive fashion. All thyronamines with tyrosyl ring iodine atoms were 5(3)-deiodinated by Dio3-containing preparations. In functional competition assays, the newly identified thyronamine substrates inhibited an established iodothyronine deiodination reaction. By contrast, thyronamines that had been excluded as deiodinase substrates in LC-MS/MS experiments failed to show any effect in the competition assays, thus verifying the former results. These data support a role for deiodinases in thyronamine biosynthesis and contribute to confining the biosynthetic pathways for 3-T 1 AM and T 0 AM.
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Environment and endocrinology: The case of thyroidology. ANNALES D'ENDOCRINOLOGIE 2008; 69:116-22. [DOI: 10.1016/j.ando.2008.02.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Potential of selected ED to interfere with TH-dependent transcriptional regulation. Exp Clin Endocrinol Diabetes 2007. [DOI: 10.1055/s-2007-972280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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4-methylbenzylidene-camphor (4MBC) causes effects comparable to primary hypothyroidism. Exp Clin Endocrinol Diabetes 2007. [DOI: 10.1055/s-2007-972421] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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An LC-MS/MS based method for the simultaneous detection of thyroid hormones and their metabolites: thyronines and thyronamines. Exp Clin Endocrinol Diabetes 2007. [DOI: 10.1055/s-2007-972278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Neuronal and ependymal expression of selenoprotein P in the human brain. J Neural Transm (Vienna) 2007; 114:877-84. [PMID: 17245539 DOI: 10.1007/s00702-006-0617-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Accepted: 12/06/2006] [Indexed: 10/23/2022]
Abstract
Selenoprotein P (SePP) is central to selenium (Se) metabolism in the mammalian organism. Human SePP contains 10 Se atoms that are covalent constituents of the polypeptide chain incorporated as the rare amino acid selenocysteine (Sec). Since hepatocytes secrete SePP into plasma, SePP is commonly regarded as a Se transport protein, although SePP mRNA is expressed in many organs. Gene targeting of SePP in mice leads to neurological dysfunction resulting from Se deficiency and associated reduction of selenoenzyme activities in the brain. However, more recent data revealed that isolated hepatic SePP deficiency does not alter brain Se levels, suggesting a role for SePP locally expressed in the brain. Some of the best characterized and most abundant selenoenzymes, glutathione peroxidases, thioredoxin reductases, and methionine sulfoxide reductase B, play major roles in the cellular defense against reactive oxygen species. Therefore, it was hypothesized that reduced brain Se bioavailability may be involved in the pathogenesis of neurodegenerative disease and normal ageing. We present evidence that human CSF contains SePP and that the human brain expresses SePP mRNA. Moreover, SePP-like immunoreactivity localizes to neurons and ependymal cells and thus appears strategically situated for maintenance and control of Se-dependent anti-oxidative defense systems.
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Effects of isoflavonoids and other plant-derived compounds on the hypothalamus–pituitary–thyroid hormone axis. Maturitas 2006. [DOI: 10.1016/j.maturitas.2006.06.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Proenkephalin A 119-159, a stable proenkephalin A precursor fragment identified in human circulation. Peptides 2006; 27:1835-40. [PMID: 16621157 DOI: 10.1016/j.peptides.2006.03.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 02/27/2006] [Accepted: 03/06/2006] [Indexed: 11/22/2022]
Abstract
In this report, we describe a newly developed sandwich immunoassay using antibodies against the proenkephalin A 119-159 peptide (PENK A 119-159). PENK A 119-159 immunoreactivity was detectable in the circulation of human blood donors and in cerebrospinal fluid (CSF) of patients without a neurologic disorder. The concentration was about 100 times higher in CSF than in serum. Analytical reversed phase HPLC revealed that PENK A 119-159 is the main immunoreactivity in human circulation and CSF. Moreover, PENK A 119-159 is stable in vitro for at least 48 h at room temperature as compared to the low stability of the peptides methionine- and leucine-enkephalin. This suggests the use of PENK A 119-159 measurement as surrogate molecule for the release of the mature peptides derived from proenkephalin A.
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Selenium and goiter prevalence in borderline iodine sufficiency. Exp Clin Endocrinol Diabetes 2006. [DOI: 10.1055/s-2006-933052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Inactivation of hepatic deiodinase expression does not alter circulating thyroid hormone levels in mice. Exp Clin Endocrinol Diabetes 2006. [DOI: 10.1055/s-2006-932901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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The selenoprotein glutathione peroxidase 3 is attached to thyroglobulin stored in the human thyroid follicular lumen. Exp Clin Endocrinol Diabetes 2006. [DOI: 10.1055/s-2006-932902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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40
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Thyroid hormone biosynthesis is a sensitive target for the action of endocrine disrupting chemicals (EDC). Exp Clin Endocrinol Diabetes 2006. [DOI: 10.1055/s-2006-932882] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Retinoic acid actions are connected with downregulation of ENO1 gene products in the follicular thyroid carcinoma cell line FTC-133. Exp Clin Endocrinol Diabetes 2006. [DOI: 10.1055/s-2006-932950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Abstract
Recent identification of new selenocysteine-containing proteins has revealed relationships between the two trace elements selenium (Se) and iodine and the hormone network. Several selenoproteins participate in the protection of thyrocytes from damage by H(2)O(2) produced for thyroid hormone biosynthesis. Iodothyronine deiodinases are selenoproteins contributing to systemic or local thyroid hormone homeostasis. The Se content in endocrine tissues (thyroid, adrenals, pituitary, testes, ovary) is higher than in many other organs. Nutritional Se depletion results in retention, whereas Se repletion is followed by a rapid accumulation of Se in endocrine tissues, reproductive organs, and the brain. Selenoproteins such as thioredoxin reductases constitute the link between the Se metabolism and the regulation of transcription by redox sensitive ligand-modulated nuclear hormone receptors. Hormones and growth factors regulate the expression of selenoproteins and, conversely, Se supply modulates hormone actions. Selenoproteins are involved in bone metabolism as well as functions of the endocrine pancreas and adrenal glands. Furthermore, spermatogenesis depends on adequate Se supply, whereas Se excess may impair ovarian function. Comparative analysis of the genomes of several life forms reveals that higher mammals contain a limited number of identical genes encoding newly detected selenocysteine-containing proteins.
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43
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The flavonoid Xanthohumol interferes with the thyroid hormone axis. Exp Clin Endocrinol Diabetes 2005. [DOI: 10.1055/s-2005-862792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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44
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Proteome analysis of the follicular thyroid carcinoma cell line FTC-133. Exp Clin Endocrinol Diabetes 2005. [DOI: 10.1055/s-2005-862941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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45
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Influence of retinoic acid on post-translational modifications of a-enolase in the human follicular thyroid carcinoma cell line FTC-133. Exp Clin Endocrinol Diabetes 2005. [DOI: 10.1055/s-2005-862998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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46
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Gender-specific differences in the expression of selenoproteins in mammals. Exp Clin Endocrinol Diabetes 2005. [DOI: 10.1055/s-2005-862874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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47
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4MBC and OMC, components of UV-sunscreens, exert organ specific alterations on type I 5'-Deiodinase activity and expression in female rats. Exp Clin Endocrinol Diabetes 2005. [DOI: 10.1055/s-2005-862997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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48
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Tissue-specific growth-defects upon Selenium-deficiency. Exp Clin Endocrinol Diabetes 2005. [DOI: 10.1055/s-2005-862936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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49
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A novel mouse model to study the importance of the liver for thyroid hormone metabolism. Exp Clin Endocrinol Diabetes 2005. [DOI: 10.1055/s-2005-862993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Abstract
Selenium (Se), once known only for its potential toxicity, is now well established as an essential trace element for mammals. Insufficient Se intake predisposes to and manifests in a variety of diseases. Recent studies have proven that it is the synthesis of selenocysteine (Sec)-containing proteins, designated selenoproteins, which represents an essential prerequisite for regular development and a long and healthy life. New transgenic mouse models analysing those selenoproteins with proven enzymatic functions displayed particular phenotypes and highlighted essential Se-dependent processes in development, growth or against specific challenges. While there is a growing molecular understanding of and general agreement on the importance of sufficiently high Se intake and undisturbed selenoprotein biosynthesis, many of the recently identified selenoproteins are still uncharacterised, and the effects and consequences of supra-physiological Se dosages are not biochemically understood. With the recent definition of the human and mouse selenoproteomes and a growing number of available tools, the Se field is now geared for a great leap forward. Se biology has already broadened our knowledge about the genetic code and about protein translation. It now holds great promises also for a better understanding of some key aspects of cancer, inflammation, fertility and prevention of age-associated diseases.
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