1,720,974 research outputs found
Strong association between serum levels of leptin and testosterone in men
No full textOBJECTIVE: Leptin serves as a hormonal signal linking food intake and energy expenditure to fat mass. As significant effects of testosterone administration on body composition and adipose tissue have been described recently, we examined a possible association between serum levels of leptin and testosterone which has not been reported so far. SUBJECTS: Three groups comprising a total of 58 adult age-matched males were included in this cross- sectional analysis by computer-assisted clinical database selection. Group 1 (n=22) consisted of untreated hypogonadal patients with testosterone serum levels lower than 7 nmol/l. The inclusion criterion for Groups II (n=20) and III (n=16) was a serum testosterone level higher than 30 nmol/l. Group II involved hypogonadal patients under effective androgen substitution therapy; Group Ill comprised males without any endocrine disorder attending our clinic. MEASUREMENTS: Morning blood samples were taken for determination of serum levels of leptin, testosterone, oestradiol and sex-hormone binding globulin (SHBG). Serum levels of leptin were measured by homologous radioimmunoassay, the other hormones by standard immunoassays. RESULTS: No significant differences in serum leptin, serum testosterone, and body mass index (BMI) were detected between Group II (3.7 ± 1.5 μg/l, 40.3 ± 7.6 nmol/l, 24.4 ± 4.9 kg/m2, respectively (mean ± SD)), and Group III (4.0 ± 2.0 μg/l, 35.9 ± 6.5 nmol/l, 24.8 ± 2.6 kg/m2, respectively). However, hypogonadal patients of Group I who were selected for low testosterone serum levels (4.3 ± 1.7 nmol/l) had significantly higher leptin serum levels of 18.8 ± 9.7 μg/l (P < 0.001) and significantly higher BMI of 30.0 ± 6.6 kg/m2 (P < 0.001). Multiple linear regression analysis revealed a significant independent association of leptin with testosterone serum levels (partial correlation coefficient =-0.84; P < 0.001) and with BMI (partial correlation coefficient = 0.44; P = 0.001), whereas serum levels of oestradiol and SHBG had no additional influence. CONCLUSIONS: This study demonstrates a close association between serum levels of testosterone and leptin in males which has not been described previously. Serum testosterone levels could be an important contributor to the known gender difference in serum leptin levels which can be found even after correction for body composition. These findings might be of clinical relevance for testosterone substitution therapy of hypogonadal as well as ageing men
The European Academy of Andrology (EAA) project “Standardizationof male genital tract colour-Doppler ultrasound parameters in healthy, fertile men”.
No full textPharmakogenetik bei der ovariellen stimulationstherapie
No full textTailoring controlled ovarian hyperstimulation (COH) to the individual patient can be challenging because the ovarian response varies substantially between patients. Pharmacogenetics has emerged as a new area of research to improve the balance between desired and undesired actions of drugs based upon the genetic predisposition of the individual patient. Clinical studies demonstrated that the p.N680S polymorphism of the FSH receptor gene determines the ovarian response to FSH stimulation in patients undergoing in vitro fertilisation. In homozygous Ser680/Ser680 type women the FSH receptor appears to be more resistant to FSH action even in normal menstrual cycles. Therefore, genotyping of patients scheduled for COH could be an attractive tool to individualise FSH dosing according to genetic differences in ovarian sensitivity. More clinical studies are warranted to investigate genotyping for the p.N680S polymorphism as a routine diagnostic test before COH
Diseases of the hypothalamus and the pituitary gland
No full textAmong males Kallmann syndrome in its fully developed form has a prevalence of about 1 in 10,000. The prevalence in males is four times higher than in females (Seminara et al. 1998). Currently the genetic defect underlying Kallmann syndrome and IHH can be demonstrated in about half of the familial cases and in about 10% of the sporadic cases. The old denomination idio-pathic hypogonadotropic hypogonadism, which reflects ignorance of the causal defect, therefore appears obsolete. The acronym IHH should stand for isolated hypogonadotropic hypogonadism, referring to the inadequacy of gonadotropin secretion as the only defect. © 2010 Springer-Verlag Berlin Heidelberg
Hormonal male contraception
No full textIntroductionMale contraception with exogenously administered hormones suppresses both luteinizing hormone and follicle stimulating hormone leading to low intratesticular testosterone concentration. This results in reversible suppression of spermatogenesis and marked decrease in sperm output in the ejaculate and preventing pregnancy in the female partner.Prior StudiesStudies of testosterone administered alone or in combination of another gonadotropin suppressive agent such as a progestin or gonadotropin releasing hormone (GnRH) analog showed decisively that the exogenous hormone administrations are effective in suppressing sperm output with few adverse events that are not anticipated. In contraceptive efficacy studies, testosterone alone or combined with a progestin are as effective in preventing pregnancies as female contraceptive methods.ConclusionHormone combinations for male contraception are in late-phase clinical trials and hold the promise of being the new, reversible contraception method for men in over half a century. Lessons learned from the male hormonal contraceptive development pave the way for new targeted approached to regulate male fertility
Report of the 7th european workshop on molecular and cellular endocrinology of the testis
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Clinical trial of transdermal testosterone and oral levonorgestrel for male contraception.
No full textApproaches to hormonal male contraception are predominantly based on injectable testosterone (T) application. As most users would prefer an injection-independent modality, this study was designed to develop a self-applicable hormonal male contraceptive regimen by combining transdermal T with an oral gestagen. Eleven healthy men (23–40 yr old) were treated with oral levonorgestrel and transdermal T for 24 weeks. T was applied daily as a transdermal patch to be worn on the trunk. Levonorgestrel was taken orally at a dose of 250 μg daily up to week 12, followed by 500 μg to week 24 in those volunteers who had not become azoospermic by that time. Within 24 weeks, 2 of 11 volunteers had become azoospermic, and 3 of 11 showed sperm concentrations below 3 million/mL. The sperm concentrations of the remaining volunteers declined, but failed to reach the limit considered compatible with contraception by WHO. Treatment resulted in suppression of LH, FSH, and sex hormone-binding globulin, whereby the volunteers with lower sperm concentrations showed more pronounced suppression than the others. Mean T concentrations remained within the lower limit of normal and on occasions were below this level. There were no complaints of hypoandrogenism. Although mean levels of low density lipoprotein cholesterol, apolipoprotein B, as well as basal and postprandial insulin increased, high density lipoprotein cholesterol and apolipoprotein A-I decreased during the treatment phase. Changes in lipid parameters were normalized within 3 weeks after cessation of medication. Although only 5 of 11 volunteers reached the target sperm counts (<3 million/mL), the study shows that a self-applicable hormonal male contraceptive could be developed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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