Endocrine Abstracts

: In community-dwelling men, salivary testosterone (Sal-T) concentrations are thought to represent tissue hormone levels and correlate strongly with serum free-T levels. Measurement of salivary glucocorticoid concentrations is a non-invasive and objective means of assessing cortisol exposure in users and non-users of hydrocortisone therapy. We assessed relationships of Sal-T with transdermal testosterone replacement therapy (TD-TRT) and with markers of testosterone exposure. I...

Traditionally, oestradiol measurement is performed by immunoassay. The sensitivity of these assays is not sufficiently sensitive for certain patient groups such as males, post-menopausal females and children. There is also a potential for interference from structurally related compounds or heterophilic antibodies. LC–MS/MS is an attractive alternative as it has increased sensitivity and specificity.We reviewed the requests for LC–MS/MS analysis...

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...

Case History: A 53 year old woman presented with a 12-month history of progressive hirsutism and deepening of her voice. Her symptoms coincided with the onset of the menopause. On clinical examination she had evidence of virilisation with muscle hypertrophy.Investigations: Biochemical tests revealed a serum testosterone (serT) of 30 nmol/l, a DHEA-Sulphate of 1.5 umol/l (1.0–12.0), an androstenedione of 3.2 nmol/l (0.0–6.0), a post-overnight de...

Introduction: Late-night salivary cortisol assessment is an important element when investigating suspected Cushing’s syndrome (CS). The goal of medical therapy is achieving a mean (of 5 samples during a single day) serum cortisol (serumF) of 150–300 nmol/l (Cushing Day Curve [CDC]). Metyrapone is an 11β-hydroxylase inhibitor elevating levels of 11-deoxycortisol causing conventional immunoassay (IA) to overestimate SerumF; a problem obviated by LC–MS/MS. We ...

Background: Accurate measurement of serum cortisol is essential in the investigation of the HPA axis. It has been documented that routine immunoassays are liable to both under- and over-recovery leading to inaccurate results and subsequent inappropriate investigations. This study seeks to provide an up-to-date assessment of the accuracy of the major immunoassay platforms and compares results to a liquid chromatography–tandem mass spectrometry (LC–MS/MS) candidate ref...

Introduction: Hypoparathyroidism is most commonly observed following neck surgery and is characterized biochemically by deficient parathyroid hormone (PTH) and hypocalcaemia alongside hyperphosphataemia and reduced 1,25-dihydroxyvitamin D. Standard treatment with oral calcium and vitamin D aims to maintain serum calcium within the low-normal range whilst avoiding hypercalciuria due to over replacement. However, concerns remain over the presence of hypercalciuria and the associ...

Introduction: Chromogranin-A (CgA) is a 49 kDa protein of the granin/secretogranin family originating from dense-core secretory granules within cells of the diffuse endocrine system. CgA is currently the best available diagnostic biomarker for neuroendocrine tumours (NETs) with recent clinical guidelines advocating the measurement of CgA as part of the baseline biochemical profile in patients presenting with symptoms suspicious of a gastroenteropancreatic NET.<p class="abs...

The accurate measurement of cortisol by immunoassay is compromised by the potential for cross-reactivity of reagent antibodies with structurally-related steroid compounds present in patient serum. This susceptibility is potentiated when normal steroid metabolism is altered pharmacologically by anti-steroidogenic drugs. This class of drug is utilised in the management of Cushing’s syndrome to moderate cortisol production. To investigate the effect of the 11β-hydroxyla...