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- Huhtaniemi, Ilpo T, et al.
(author)
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Effect of Polymorphisms in Selected Genes Involved in Pituitary-Testicular Function on Reproductive Hormones and Phenotype in Aging Men.
- 2010
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In: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 95, s. 1898-1908
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Journal article (peer-reviewed)abstract
- Context: Polymorphisms in genes involved in regulation, biosynthesis, metabolism, and actions of testicular sex hormones may influence hormone balance and phenotype of aging men. Objective: We investigated the relationships between polymorphisms in genes related to pituitary-testicular endocrine function and health status. Design and Setting: Using cross-sectional baseline data, we conducted a multinational prospective cohort observational study consisting of a population survey of community-dwelling men. Participants: A total of 2748 men, aged 40-79 (mean +/- SD, 60.2 + 11.2) yr, were randomly recruited from eight European centers. Forty-three polymorphisms were genotyped in the following genes: androgen receptor (AR), estrogen receptor-alpha and -beta (ESR1 and ESR2), steroid 5alpha-reductase type II (SRD5A2), 17alpha-hydroxylase/17,20-lyase (CYP17A1), aromatase (CYP19A1), sex hormone-binding globulin (SHBG), LH beta-subunit (LHB), and LH receptor (LHCGR). Main Outcome Measures: We measured the associations between gene polymorphisms and endocrine, metabolic, and phenotypic parameters related to aging and sex hormone action. Results: Several polymorphisms in SHBG, ESR2, AR, CYP19A1, and LHB were significantly associated with circulating levels of SHBG, LH, total, free, and bioavailable testosterone and estradiol, the LH x testosterone product, and indices of insulin sensitivity. Apart from several previously reported associations between genes affecting estrogen levels and heel ultrasound parameters, no associations existed between polymorphisms and nonhormonal variables (anthropometry, blood lipids, blood pressure, hemoglobin, prostate symptoms, prostate-specific antigen, sexual dysfunction, cognition). Conclusion: In aging men, polymorphisms in genes related to the pituitary-testicular endocrine function significantly influence circulating LH, testosterone, and estradiol levels, but the downstream effects may be too small to influence secondary phenotypic parameters.
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| 2. |
- Huhtaniemi, Ilpo T, et al.
(author)
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Increased Estrogen Rather Than Decreased Androgen Action Is Associated with Longer Androgen Receptor CAG Repeats.
- 2009
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In: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 94, s. 277-284
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Journal article (peer-reviewed)abstract
- Context: The individual variability in the waning androgenic-anabolic functions of aging men may be influenced by the CAG repeat polymorphism in exon 1 of the androgen receptor (AR), affecting androgen sensitivity. However, findings on its phenotypic effects are inconclusive. Objective: To investigate the relationships between health status, various reproductive hormones and the AR CAG repeat length. Design: A multi-national prospective cohort observational study - cross-sectional baseline data. Setting: Population survey of community-dwelling men. Participants: Men (40-79-yr-old; n=3,369) randomly recruited from centers in eight European countries; CAG repeat analysis was performed in 2,878 men. Main outcome measures: The correlations of the CAG repeat length with selected endocrine, metabolic and phenotypic parameters related to aging and sex hormone action. Results: Only minor differences were found in CAG repeat lengths between the eight European countries. They showed significant positive association with total, free and bioavailable levels of testosterone (T) and estradiol (E2). FSH but not LH correlated inversely with CAG repeat length. Significant associations were found with bone ultrasound parameters at the calcaneus. Negative correlation was found with triglycerides, but not with other blood lipids, or with anthropometry, blood pressure, hemoglobin, insulin sensitivity, or sexual and prostatic functions. Conclusions: The AR CAG repeat length correlates significantly with serum T and E2 of aging men. Weaker transcriptional activity of the AR with longer CAG-encoded polyglutamine repeats appears to be totally or near-totally compensated for by higher T levels. The residual phenotypic correlations may reflect differences in estrogen levels/actions following aromatization of the higher T levels.
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| 3. |
- Tajar, Abdelouahid, et al.
(author)
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Characteristics of Secondary, Primary, and Compensated Hypogonadism in Aging Men: Evidence from the European Male Ageing Study.
- 2010
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In: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 95, s. 1810-1818
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Journal article (peer-reviewed)abstract
- Context: The diagnosis of late-onset hypogonadism (LOH) in older men with age-related declines in testosterone (T) is currently not well characterized. Objective: Our objective was to investigate whether different forms of hypogonadism can be distinguished among aging men. Design: The study was a cross-sectional survey on 3369 community-dwelling men aged 40-79 yr in eight European centers. Methods: Four groups of subjects were defined: eugonadal (normal T and normal LH), secondary (low T and low/normal LH), primary (low T and elevated LH), and compensated (normal T and elevated LH) hypogonadism. Relationships between the defined gonadal status with potential risk factors and clinical symptoms were investigated by multilevel regression models. Results: Among the men, 11.8, 2.0, and 9.5% were classified into the secondary, primary, and compensated hypogonadism categories, respectively. Older men were more likely to have primary [relative risk ratio (RRR) = 3.04; P < 0.001] and compensated (RRR = 2.41; P < 0.001) hypogonadism. Body mass index of 30 kg/m(2) or higher was associated with secondary hypogonadism (RRR = 8.74; P < 0.001). Comorbidity was associated with both secondary and primary hypogonadism. Sexual symptoms were more prevalent in secondary and primary hypogonadism, whereas physical symptoms were more likely in compensated hypogonadism. Conclusions: Symptomatic elderly men considered to have LOH can be differentiated on the basis of endocrine and clinical features and predisposing risk factors. Secondary hypogonadism is associated with obesity and primary hypogonadism predominately with age. Compensated hypogonadism can be considered a distinct clinical state associated with aging. Classification of LOH into different categories by combining LH with T may improve the diagnosis and management of LOH.
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| 4. |
- Tajar, Abdelouahid, et al.
(author)
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Frailty in Relation to Variations in Hormone Levels of the Hypothalamic-Pituitary-Testicular Axis in Older Men: Results From the European Male Aging Study.
- 2011
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In: Journal of the American Geriatrics Society. - : Wiley. - 0002-8614. ; 59:5, s. 814-821
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Journal article (peer-reviewed)abstract
- OBJECTIVES: To explore the associations between frailty and reproductive axis hormones (as an important regulatory system) in middle aged and older men. DESIGN: Cross-sectional. SETTING: The European Male Aging Study. PARTICIPANTS: Three thousand two hundred nineteen community-dwelling European men aged 40 to 79. MEASUREMENTS: Interviewer-assisted questionnaires to assess physical activity, health status, and mood were administered. Testosterone (T), luteinizing hormone (LH), follicle-stimulating hormone (FSH), dehydroepiandrosterone sulfate (DHEAS), and sex hormone-binding globulin (SHBG) were measured in a fasting morning blood sample. Frailty was assessed as an index (FI) according to the number (out of 43 possible) of health deficits (symptoms, signs, and functional impairments). Relationships between FI and hormone levels (as outcomes) were explored using regression models. RESULTS: Mean FI was 0.12 ± 0.11 (range 0-0.67) was highest in the oldest group. After adjustment for confounders, higher levels of FI were significantly associated with lower levels of total T, free T, and DHEAS and higher levels of gonadotropins and SHBG; a 1-standard deviation cross-sectional increase in FI was associated with a regression coefficient of -0.30 nmol/L (95% confidence interval (CI)=-0.53 to -0.07) decrease in total T and 0.66 U/L (95% CI=0.48-0.83) increase in LH. CONCLUSIONS: The associations between high FI, high gonadotropins, and well-maintained circulating T suggest that these changes are markers of aging-related disruptions of multiple physiological regulation, of which alterations in pituitary-testicular function represent a sensitive marker rather than an underlying pathogenic mechanism for frailty.
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