Endocrine Abstracts

Osteoarthritis (OA) may be associated with endocrine disorders such as hypothyroidism, obesity, primary hyperparathyroidism or acromegaly, although often its cause remains undefined. To facilitate investigations of the underlying molecular mechanisms of OA we have investigated N-ethyl-N-nitrosourea (ENU) mutant mice using a genotype-driven approach in which candidate genes are examined for mutations. One such investigated gene is growth and differentiation factor...

The calcium sensing receptor (CaSR) is a G protein coupled receptor that is expressed in type A intercalated cells of the distal convoluted tubule and cortical collecting ducts, where it is involved in renal proton excretion. We have therefore investigated the Nuf mouse, which has an activating CaSR mutation (Leu723Gln) that leads to hypocalcaemia, hypercalciuria, renal calcification, a urinary concentrating defect, and cataracts, for disturbances in acid-base homeostasis. Mic...

The calcium-sensing receptor (CaSR) is a G protein coupled receptor that is expressed widely, including pancreatic beta cells where it has been shown to modulate insulin secretion in vitro. However, the role of the CaSR in regulating in vivo insulin secretion and glucose homeostasis remains unknown. We have therefore investigated the Nuf mouse, which has an activating CaSR mutation (Leu723Gln), to determine whether abnormal CaSR function in vivo affects gl...

Familial juvenile hyperuricaemic nephropathy (FJHN), an autosomal dominant disorder characterised by raised serum urate, reduced fractional excretion of uric acid (FEUA), a urine concentrating defect, and progressive renal failure, is caused by mutations in the UMOD gene, encoding uromodulin (Tamm–Horsfall glycoprotein). The FJHN-causing UMOD mutations are missense mutations (>90%) or inframe deletions (<10%), and none result in prematurely truncated...

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of disease spanning from simple steatosis to non-alcoholic steatohepatitis (NASH) with risk of progression to fibrosis and eventually cirrhosis. Dysfunction of the gut-liver axis plays a role the progression to NASH. Intestinal damage and increased permeability can increase the delivery of pathogen-associated molecular patterns (PAMPs), such as LPS and intact bacteria, to the liver where they can activate the TLR4 signall...

Bile acids (BA) are potent steroid hormones that mediate a variety of metabolic effects. They play a pivotal role in cholesterol catabolism, intestine nutrient absorption, and regulate lipid, glucose and energy metabolism. 5-Beta-Reductase (AKR1D1) is a key enzyme in the BA synthesis pathway, required for cholesterol metabolism into bile acids. We generated a novel global AKR1D1 knockout (KO) mouse which, as expected, has decreased total serum and hepatic BAs and altered BA co...

Steroid hormones and bile acids are potent regulators of metabolism. The enzyme 5β-reductase (AKR1D1) has a crucial role in bile acid synthesis and also generates 5β-reduced dihydrosteroid metabolites, regulating intra-cellular steroid availability though the clearance of cortisol, testosterone, androstenedione, and progesterone. As AKR1D1 sits at the interface of bile acid synthesis and steroid metabolism, we have hypothesised that it plays a key role in metabolic h...

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...

Kyphosis and scoliosis are common spinal disorders that lead to significant morbidity in childhood, adolescence and adulthood. Familial and twin studies have implicated a genetic involvement, although the causative genes remain to be identified. To facilitate these studies, we investigated 12-week-old progeny of mice treated with the chemical mutagen N-ethyl-N-nitrosourea (ENU) using phenotypic assessments that included dysmorphology, radiography and dual-energy ...

The G-protein coupled calcium-sensing-receptor (CaSR) regulates calcium homeostasis and inactivating mutations result in familial hypocalciuric hypercalcaemia (FHH), whilst activating mutations result in autosomal dominant hypocalcaemia with hypercalciuria (ADHH). Allosteric CaSR modulators consist of: calcimimetics, which activate the CaSR e.g. Cinacalcet, that is used to treat the hypercalcaemia of chronic renal failure and metastatic parathyroid carcinoma; and calcilytics e...