Endocrine Abstracts

Marshall-Smith syndrome (MSS) is a congenital disorder affecting skeletal and neural development, due to mutations in the nuclear factor I/X (NFIX) gene. NFIX encodes a ubiquitously expressed transcription factor that regulates the expression of viral and cellular genes. To identify novel genes that are misregulated by NFIX mutations, RNA sequencing and proteomics analyses were performed on mouse embryonic fibroblast (MEF) cells derived from a repres...

Lactation promotes infant development and confers long-term health benefits to mothers and infants. However, the endocrine and paracrine mechanisms mediating milk synthesis remain to be fully elucidated. Hormones such as prolactin and progesterone trigger the onset of lactation, whereas local mammary factors are considered to play a greater role in the maintenance of milk synthesis. We hypothesised that mammary epithelial cytokines are required for established lactation, and u...

Heterozygous germline gain-of-function mutations of the extracellular calcium-sensing receptor (CaSR), a G-protein coupled receptor (GPCR), result in autosomal dominant hypocalcaemia type 1 (ADH1), which may cause symptomatic hypocalcaemia with low circulating parathyroid hormone (PTH) concentrations and hypercalciuria. Negative allosteric CaSR modulators, known as calcilytics, rectify the gain-of-function caused by CaSR mutations and are a potential targeted therapy for ADH1....

Familial hypocalciuric hypercalcaemia (FHH) comprises three genetic variants: FHH types 1 and 2 are due to mutations of the calcium-sensing receptor (CaSR) and G-protein subunit alpha-11, whereas, FHH type 3 (FHH3) is caused by heterozygous mutations affecting the Arg15 residue (Arg15Cys, Arg15His, Arg15Leu) of the adaptor-related protein complex 2-sigma subunit (AP2S1), which regulates CaSR endocytosis. FHH is usually associated with mild hypercalcaemia, normal parathyroid ho...

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...

In the pathogenesis of obesity, dysregulated tissue cortisol metabolism (controlled by 11β-HSD1), is postulated to be involved. Fifteen patients (seven mens, mean BMI 50.8±7 kg/m2) awaiting Roux En Y gastric Bypass (RYGB) surgery underwent assessment of 11β-HSD1 activity using cortisol generation profile. Corticosteroids in serum and subcutaneous adipose tissue microdialysis fluid and urinary corticosteroid metabolites were analysed by liquid and gas ...

G-protein subunit α-11 (Gα11), which is encoded by GNA11, plays a major role in calcium homeostasis by regulating parathyroid hormone (PTH) secretion, and germline loss-of-function mutations cause familial hypocalciuric hypercalcaemia type 2 (FHH2). Since Gα11 is ubiquitously expressed, we investigated whether FHH2 is associated with additional non-calcitropic phenotypes by analysing mice harbouring a homozygous germline deletion o...

The calcium-sensing-receptor (CaSR) is a G-protein-coupled receptor that plays a fundamental role in extracellular calcium homeostasis, but is also implicated in non-calcitropic disorders including colon cancer and asthma. In addition, CaSR is highly expressed in pancreatic islets where it has a role in insulin secretion. Patients with gain-of-function CaSR mutations, and mice (referred to as Nuf) with a gain-of-function CaSR mutation (Leu723Gln), develop autosomal dominant hy...

Renal stone disease is a common disorder for which the underlying causes remain largely unknown. We have investigated a hereditary renal calcification mouse model, Rcalc1, that is not associated with hypercalciuria for underlying mechanisms. Kidney RNA from 30 to 33 week-old Rcalc1 and control BALB/c and C3H female mice (n=4/group) was extracted and hybridised to Mouse Genome 430 2.0 arrays (Affymetrix). Following Robust Multichip Average normalization, pair-wise compar...

Vascular calcification, occurring in organs such as heart and kidneys, is associated with increased risk of cardiovascular mortality. The underlying molecular mechanisms remain unknown. To elucidate these, we investigated C3H mice, an inbred strain susceptible to vascular, myocardial and renal calcification. Myocardial calcification in C3H mice involves 4 genetic loci, Dyscalc1-4, that map to chromosomes 7, 4, 12 and 14, respectively. Dyscalc1 contributes to myoc...