Endocrine Abstracts

Introduction: We have developed a highly sensitive LC–MS assay in an attempt to improve the measurement of salivary testosterone in female samples.Methods: A 200 μl saliva sample, calibrators or QC were mixed with 10 μl working internal standard (0.1 μg/l) and 1 ml of methyl tert-butyl ether (MTBE). Vortex mixed for 4 min and frozen at −80 °C (1 h). Unfrozen organic layer was transferred to a glass tube and evaporated. The ...

Clinical guidance recommends titrating the dose of metyrapone against serum cortisol concentrations. These serum samples are usually measured by immunoassays; however it has been well documented that there are interferences in these assays in patients with altered steroid metabolism due to a pathological process or drug treatment. The increasing availability of mass spectrometry (MS) assays for steroid hormones may circumvent this issue and assays that measure multiple steroid...

Androsterone glucuronide (ADG) is a major metabolite of the androgen dihydrotestosterone and has also been shown to arise from the intracrine conversion of other adrenal androgens such as androstenedione and androsterone. ADG has been shown to be raised in some women with clinical signs of hyperandrogenism such as acne and hirsutism, even when levels of androgens, e.g. testosterone or DHEA-S are normal. This indicates that raised ADG levels may be an early indication of hypera...

Testosterone, androstenedione and DHEAS are commonly measured by immunoassays. Variations in antibody specificity and calibration of assays results in non-commutability of measurements. Even more specific mass spectrometry (LC–MS/MS) assays still exhibit differences in calibration. As the use of mass spectrometry for measuring steroids is becoming more common in the clinical laboratory, the development of LC–MS/MS reference ranges for these analytes is essential to h...

Salivary cortisol (SalC) potentially has advantages over serum cortisol (SerC) as it is easier to collect and possibly reflects unbound (free) cortisol. SalC levels are approximately 10 times lower than SerC and require high measurement precision best addressed by liquid chromatography–tandem mass spectrometry (LC-MS/MS), which in contrast to previously used radioimmunoassays eliminates cross-reactivity by other steroids. We describe the use of LC-MS/MS to evaluate the po...

Introduction: 7α-Hydroxy-4-cholesten-3-one (C4) is the common intermediary of the primary bile acids (BAs). Its concentration in serum correlates with the rate of activity of hepatic CYP7A1 and therefore with the rate of hepatic BA production. Previous work has smggested a role for BA pool dysregulation in the metabolic syndrome and gut dysbiosis seen in polycystic ovary syndrome (PCOS). However, the mechanism of this is still to be elucidated. Here we report a novel LC-M...

Background: Polycystic ovary syndrome (PCOS) is a heterogenous condition that affects approximately 12% of females. The diagnosis can be complex and biochemistry tests are routinely relied upon to help identify hyperandrogenaemia and to exclude other conditions. However, although national and international guidelines advocate the use biochemistry tests, little information is provided as to which tests should be used and which other endocrinopathies should be excluded.<p cl...

Background: The 1 mg overnight dexamethasone suppression test (ONDST) is recommended for the differential diagnosis of Cushing’s syndrome and the investigation of adrenal incidentalomas. However, diagnostic performance of the test relies on accurate methods to quantitate cortisol in serum. Although the variable performance of serum cortisol immunoassays has been well-documented, little has been published on their performance following the ONDST.Aims...

Sex hormone binding globulin (SHBG) is a glycoprotein which binds hormones such as testosterone. Around 97% of circulating testosterone is bound to SHBG and is therefore biologically unavailable; approximately 2–3% of testosterone is free or loosely bound to proteins such as albumin, and is biologically active, or bioavailable. Free testosterone is very technically challenging to quantify; in order to circumvent this problem, equations are used...

Sex hormone binding globulin (SHBG) is a glycoprotein which binds hormones such as testosterone. Around 97% of circulating testosterone is bound to SHBG and is therefore biologically unavailable; approximately 2–3% of testosterone is free or loosely bound to proteins such as albumin, and is biologically active, or bioavailable. Free testosterone is very technically challenging to quantify; in order to circumvent this problem, equations are used...