Anabolic and catabolic hormonal response of elite runners to training at high altitude

A 2-week training period 2000 meters above sea level performed by 6 male elite Swedish runners influenced neither basal anabolic (total and non-sex hormone-binding globulin (SHBG)-bound testosterone (NST) and insulin-like growth factor-1 (IGF-1) nor catabolic (cortisol) hormones when comparing serum levels prior to and after the training camp. The anabolic vs catabolic hormone balance, expressed as the NST: cortisol ratio, also remained unchanged as well as SHBG and body mass. Thus, training at 2000 meters above sea level, often practised by elite runners to improve performance in competition at sea level, does not result in a catabolic situation after return to sea level, as measured by peripheral hormones. However, the adaptation to high altitude was associated with a slight (NS) decrease in testosterone as well as in anabolic vs catabolic balance as measured the third day at high altitude. Simultaneously, a decrease in subjective performance was claimed by the runners, but could not be shown by objective measurements. From day 3 to day 9 at high altitude, all runners claimed a subjective recuperation of performance. Total and non-SHBG-bound testosterone increased significantly from day 3 at high altitude to the first post-camp sea-level test. The results reflect the necessity of adaptation when travelling to races at different altitudes. The Swedish runners had significantly higher cortisol, total testosterone and NST levels compared with basal values of a group of 17 elite Kenyan runners living and training at high altitude. Since the NST cortisol and IGF-1 values were not lower, a catabolic state or malnutrition was not likely to be present. The results might reflect an adaptation to altitude or ethnic variations.     

Monitoring testosterone levels in testosterone-treated men

Dose adjustment with transdermal testosterone preparations should recognize the variability of serum total testosterone levels between applications and over the course of 24?h. Dose adjustments are also made difficult by between-laboratory assay variability. Low SHBG with obesity and diabetes lowers the total testosterone level, and free or bioavailable testosterone may prove to be a better choice for monitoring the progress and dosing of testosterone-treated men with adult onset hypogonadism.     

复发性流产伴胰岛素抵抗患者的中医体质分析

目的探讨复发性流产伴胰岛素抵抗患者的中医体质分布特征,了解此类患者血清SHBG、PAI-1水平,并探讨其与中医体质的关联性。方法采用横断面问卷调查形式,选择复发性流产伴胰岛素抵抗患者92例(观察组)和复发性流产不伴胰岛素抵抗患者92例(对照组),比较两组中医体质及血清SHBG及PAI-1水平进行统计分析。结果观察组中医体质类型以阳虚质(27.01%)、气郁质(13.79%)、痰湿质(12.07%)为主,对照组以阳虚质(34.67%)、气郁质(13.33%)、阴虚质(11.33%)为主,两组痰湿质差异有统计学意义(P<0.05)。观察组中血清SHBG的表达水平为(9.692.78)nmol/ml,对照组中血清SHBG的表达水平为(11.09±2.56)nmol/ml,观察组中血清SHBG表达水平低于对照组,差异具有统计学意义(P<0.05)。观察组中血清PAI-1的表达水平为(11,056.1±1631.8)pg/ml,对照组中血清PAI-1的表达水平为(10,302.7±1688.8)pg/ml,观察组中血清PAI-1的表达高于对照组,差异有统计学意义(P<0.05)。复发性流产伴胰岛素抵抗患者不同的中医体质类型中阳虚质的SHBG表达水平为(9.51±3.14)nmol/ml,气郁质SHBG表达水平为(9.96±2.94)nmol/ml,痰湿质SHBG表达水平为(9.94±2.50)nmol/ml,各组间比较差异无统计学意义(P>0.05)。阳虚质的PAI-1表达水平为(11,241.6±1701.7)pg/ml,气郁质PAI-1表达水平为(10,739.3±1334.6)pg/ml,痰湿质PAI-1表达水平为(11,046.7±1372.1)pg/ml,各组间比较差异无统计学意义(P>0.05)。结论复发性流产伴胰岛素抵抗患者中医体质以阳虚质、气郁质、痰湿质为主。血清SHBG水平在复发,性流产伴胰岛素抵抗患者表达偏低,血清PAI-1水平在复发性流产伴胰岛素抵抗患者表达升高。     

Cryptorchidism and endocrine disrupting chemicals

Prospective clinical studies have suggested that the rate of congenital cryptorchidism has increased since the 1950s. It has been hypothesized that this may be related to environmental factors. Testicular descent occurs in two phases controlled by Leydig cell-derived hormones insulin-like peptide 3 (INSL3) and testosterone. Disorders in fetal androgen production/action or suppression of Insl3 are mechanisms causing cryptorchidism in rodents. In humans, prenatal exposure to potent estrogen diethylstilbestrol (DES) has been associated with increased risk of cryptorchidism. In addition, epidemiological studies have suggested that exposure to pesticides may also be associated with cryptorchidism. Some case-control studies analyzing environmental chemical levels in maternal breast milk samples have reported associations between cryptorchidism and chemical levels. Furthermore, it has been suggested that exposure levels of some chemicals may be associated with infant reproductive hormone levels.     

性激素结合球蛋白与2型糖尿病及肥胖

性激素结合球蛋白(SHBG)是由肝脏产生的一种糖蛋白,通过与组织细胞表面的特异性受体结合介导和(或)直接激活腺苷酸环化酶系统,从而调节组织细胞功能.研究显示,SHBG与2型糖尿病和肥胖相关,可反映肥胖2型糖尿病患者的胰岛素抵抗程度.低SHBG水平可增加胰岛素抵抗及2型糖尿病的发病风险,可导致腹型肥胖.高血清SHBG通过...     

The relationship between endogenous estrogen,sex hormone-binding globulin,and bone loss in female residents of a rural Japanese community: the Taiji Study

 The aim of this study was to clarify the relationship between endogenous estrogen, sex hormone-binding globulin (SHBG), and bone loss in pre-, peri-, and postmenopausal female residents of Taiji, a rural Japanese community. From a list of inhabitants aged 40 to 79 years, 200 participants—50 women in each of four age decades—were randomly selected, and baseline bone mineral density (BMD) at the lumbar spine and proximal femur were measured by dual-energy X-ray absorptiometry in 1993. Total estradiol (total E2) and SHBG were measured, and SHBG-unbound E2 (UBE2) was calculated using SHBG and the percent SHBG-unbound fraction ratio. BMD was measured again 3 years later, in 1996. Participants with ovariectomy or hysterectomy were excluded, and the remaining participants were categorized into four groups: premenopausal (n= 38), perimenopausal (n= 14), postmenopausal group 1 (5 years or less since menopause; n= 18), and postmenopausal group 2 (6 years or more since menopause; n= 74). The mean value of total E2 was highest in the premenopausal group (49.1 pg/ml), followed by the perimenopausal group (26.4 pg/ml), and the postmenopausal groups (0.83 pg/ml in postmenopausal group 1 and 0.96 pg/ml in postmenopausal group 2). The means for UBE2 showed the same pattern across the groups. After the multiple regression analysis of BMD at follow-up and endogenous estrogens, in premenopausal women, there were no significant associations between BMD at follow-up and serum total E2 and UBE2. In perimenopausal women, however, serum total E2 and UBE2 were significantly correlated with trochanteric BMD at follow-up (P < 0.05); and in postmenopausal group 2, they were significantly correlated with lumbar spine and Ward's triangle BMD at follow-up (P < 0.001 at lumbar spine, P < 0.05 at Ward's triangle). Concerning the association between BMD at follow-up and SHBG, in the premenopausal group, serum levels of SHBG were negatively correlated with BMD at the femoral neck (P < 0.05). In regard to partial regression coefficients for the change rates of BMD over 3 years and serum estrogens and SHBG concentrations, in perimenopausal women, UBE2 was correlated with the change rate of BMD at Ward's triangle (P < 0.05), and in postmenopausal group 1, serum levels of SHBG were significantly negatively related to change in BMD at the trochanter (P < 0.01). No other relationships with change in BMD were observed at any sites. These findings suggest that serum E2, UBE2, and SHBG levels differentially predict BMD levels in groups of differing menstrual status. It would, however, be difficult to predict bone loss in middle-aged and elderly Japanese women over a 3-year period using these indices alone. Received: November 29, 2001 / Accepted: February 28, 2002     

Hormonal changes and their impact on cognition and mental health of ageing men

Demographic changes resulting in ageing of the world's population have major implications for health. As men grow older, circulating levels of the principal androgen or male sex hormone testosterone (T) decline, while the prevalence of ill-health increases. Observational studies in middle-aged and older men have shown associations between lower levels of T and poorer mental health in older men, including worse cognitive performance, dementia and presence of depressive symptoms. The role of T metabolites, the more potent androgen dihydrotestosterone (DHT) and the oestrogen receptor ligand estradiol (E2) in the pathophysiology of cognitive decline are unclear. Studies of men undergoing androgen deprivation therapy in the setting of prostate cancer have shown subtle detrimental effects of reduced T levels on cognitive performance. Randomised trials of T supplementation in older men have been limited in size and produced variable results, with some studies showing improvement in specific tests of cognitive function. Interventional data from trials of T therapy in men with dementia are limited. Lower levels of T have also been associated with depressive symptoms in older men. Some studies have reported an effect of T therapy to improve mood and depressive symptoms in men with low or low-normal T levels. T supplementation should be considered in men with a diagnosis of androgen deficiency. Beyond this clinical indication, further research is needed to establish the benefits of T supplementation in older men at risk of deteriorating cognition and mental health.