Endocrine Abstracts

The hepatic peptide hormone hepcidin is the principal regulator of iron absorption and tissue iron distribution. Hepcidin circulates in blood plasma and acts at nanomolar concentrations by inducing degradation of its receptor, the cellular iron exporter ferroportin. Ferroportin exports iron into plasma from absorptive enterocytes, from macrophages that recycle the iron of senescent erythrocytes, and from hepatocytes that store iron. Therefore, hepcidin-mediated degradation of ...

The cell surface calcium receptor is the primary molecular entity regulating secretion of parathyroid hormone (PTH). Activation of this receptor by extracellular calcium inhibits PTH secretion whereas blocking the calcium receptor stimulates secretion of PTH. Chronically elevated levels of PTH, as occurs in hyperparathyroidism, stimulate bone resorption whereas temporary increases in circulating levels of PTH stimulate bone formation. This stimulatory effect on bone has prompt...

Klinefelter syndrome is an abnormality of sexual development which is usually characterised by the chromosome complement of 47,XXY, although occasionally patients may have multiple X or Y chromosomes, may be mosaic with 46, XY, 47,XXY or have an X-autosome translocation. We present the case of a 43 year old male patient with the phenotypic appearance of Klinefelter syndrome and primary infertility, who was found on karyotype analysis to have an hitherto undescribed inversion o...

Background: Although the role of hypermethylation of certain tumor suppressor genes are known in pituitary adenomas little information is available regarding whole methylation-demethylation status and especially regarding its correlation with clinical parameters. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) is an easy and accurate method to detect the level of methylcytosine (5 mC) and the demethylation intermedier hydroxymethylcytosine (5 hmC) ...

The total 25-hydroxy-vitamin-D (t-25OHD) level reflects the vitamin-D supply, but it is also influenced by the levels of vitamin-D-binding-proteins (DBP) and albumin. The type of dialysis influences the levels of serum proteins. The ‘free-hormone hypothesis’ states that only the free molecules (f25OHD) can diffuse intracellular. Our aim was to evaluate the total, calculated (c-f25OHD) and direct measured (dm-f25OHD) 25OHD levels in patients with chronic renal disease...

Autosomal dominant hypocalcemia type 1 (ADH1), caused by gain-of-function calcium-sensing receptor gene (CASR) variants, is characterized by low parathyroid hormone (PTH) levels, hypocalcemia, hypercalciuria, hyperphosphatemia and hypomagnesemia. Conventional therapy (calcium and active vitamin D) worsens hypercalciuria, which may result in renal complications. Calcilytics, such as encaleret, are negative allosteric modulators of the calcium-sensing receptor (CaSR). T...

Autosomal dominant hypocalcaemia type 1 (ADH1) is a systemic disorder of calcium homeostasis caused by gain-of-function mutations of the calcium-sensing receptor (CaSR). ADH1 may lead to symptomatic hypocalcaemia, inappropriately low parathyroid hormone (PTH) concentrations and hypercalciuria. Active vitamin D metabolites are the mainstay of treatment for symptomatic ADH1 patients, however their use predisposes to nephrocalcinosis, nephrolithiasis and renal impairment. Calcily...

A 32-year-old women initially presented with recurrent kidney stones and was found to have nephrocalcinosis. She was found to normocalcaemic but hypercalciuric, with a plasma ionized calcium at upper-limit of normal and a PTH in lower normal range. One year later, during the first trimester of a pregnancy, she presented with severe hypercalcaemia, hypercalciuria and suppression of PTH. Extensive investigations for causes of hypercalcaemia excluded hyperparathyroidism, other en...

Introduction: Disrupted mitochondrial functions and genetic variations of mitochondrial DNA (mtDNA) have been observed in different tumors. Regarding pituitary adenomas mtDNA was evaluated only in oncocytic type using PCR based methods and it showed high prevalence of Complex I variants. Next generation sequencing (NGS) allows high throughput sequencing and it is useful for accurate identification of heteroplasmy of mitochondrial genome as well.Aim: We a...

Autosomal dominant hypocalcemia type 1 (ADH1), caused by gain-of-function variants in the calcium-sensing receptor (CaSR, gene: CASR) and is characterized by hypocalcemia, hyperphosphatemia, low parathyroid hormone (PTH), and hypercalciuria. Calcilytics (negative allosteric modulators of the CaSR) decrease the sensitivity of activated receptors to extracellular calcium and normalize blood and urine abnormalities in ADH1 rodent models. Encaleret is an oral calcilytic u...