Endocrine Abstracts

The relation between testosterone (T) production and action is complex, involving protein binding in the circulation affecting clearance and tissue availability, T production from precursors in peripheral tissues, deactivating and activating (to dihydrotestosterone and estradiol) metabolism within target tissues, besides factors affecting androgen responsiveness (receptor concentrations, cofactors, genetics,…). Yet, in absence of a useful independent marker of androgen a...

The relation between testosterone (T) production and action is complex, involving protein binding in the circulation affecting clearance and tissue availability, T production from precursors in peripheral tissues, deactivating and activating (to dihydrotestosterone and estradiol) metabolism within target tissues, besides factors affecting androgen responsiveness (receptor concentrations, cofactors, genetics,…). Yet, in absence of a useful independent marker of androgen a...

Pubertal exposure to rising blood concentrations of sex steroids, partly in concert with transiently increased activity of the somatotropic axis, is instrumental in a pubertal acceleration of bone growth and acquisition of bone mass, followed by growth inhibition and closure of the epiphyseal cartilages in late puberty. As is illustrated by experiments of nature, i.e. subjects with aromatase deficiency or lack of functional oestrogen receptor α, and with androgen insensit...

Background: In men with obesity and the metabolic syndrome there is an increased prevalence of low serum testosterone. Overweight and moderate obesity is associated mainly with low total testosterone (T) secondary to decreased concentrations of SHBG, which are strongly inversely associated with indices of adiposity and insulin resistance, and preserved free T levels. In more severe obesity and metabolic abnormalities (often with type 2 diabetes) low total T can be accompanied ...

Introduction: Current clinical practice guidelines recognise that a calculated free testosterone (T) level is the single most-useful, clinically sensitive marker of androgen excess in women, but there is no clear guidance as to the best way to measure free T. Several equations have been proposed to calculate clinically useful estimates of free T including the free androgen index (FAI) and calculated free T (cFT). The FAI is not used in men but it is...

Introduction: Current clinical practice guidelines recognise that a calculated free testosterone (T) level is the single most-useful, clinically sensitive marker of androgen excess in women, but there is no clear guidance as to the best way to measure free T. Several equations have been proposed to calculate clinically useful estimates of free T including the free androgen index (FAI) and calculated free T (cFT). The FAI is not used in men but it is...

Introduction: Given the importance of establishing a reliable diagnosis of impaired glucose metabolism and diabetes mellitus (DM), knowledge on accurate and reproducible parameters is needed. However, little is known on the reproducibility of fasting and oral glucose tolerance test (OGTT) derived parameters, especially with respect to the 2-hour derived parameters.Objectives: To determine reproducibility of parameters of glucose metabolism in a non-diabe...

Background: Impaired bone geometry and/or aberrant bone matrix formation may underlie the increased fracture risk observed in patients with type 1 diabetes mellitus (T1DM). Although reduced areal and volumetric bone mineral density (aBMD, vBMD) have been observed in pediatric and adolescent T1DM patients, few studies have confirmed these observations in adults. Moreover, data on bone geometry in T1DM remain scarce.Objective: To compare areal and volumetr...

Objective: In type 2 diabetes mellitus, fracture risk is increased despite preserved BMD. This might in part be due to insulin resistance affecting bone geometry; however, studies investigating the associations of insulin sensitivity with bone geometry are lacking. We aimed to explore this relationship in a cohort of healthy, young adult men.Methods: In 1001 healthy men aged 25–45 years, cortical bone geometry was assessed using pQCT (radius and tib...

Introduction: Gender differences in insulin resistance, body composition and lipid profile are well known and related to sex steroid hormones. In this study, we examine the metabolic profile of transsexual persons undergoing drastic sex steroid changes, during the first year of hormonal therapy.Design: This research is part of a prospective intervention study conducted in several European gender teams (Ghent, Oslo, Amsterdam, and Florence).<p class="...