Endocrine Abstracts

A role for glucocorticoids (GCs) in the regulation of carbohydrate metabolism and the development of diabetes was first described over 70 years ago. Whilst there is little doubt that systemic GC excess leads to insulin resistance the tissue specific mechanisms underpinning their effect on insulin sensitivity remain to be understood. We have defined tissue specific effects of GCs on insulin sensitivity and lipid metabolism in vitro and in vivo. In skeletal myotube...

Thyroid diseases are common disorders. Globally, hypothyroidism is still frequently caused by iodine deficiency. In iodine sufficient areas, the most common cause of hypothyroidism is thyroid autoimmunity. Subclinical hypothyroidism is defined as elevated thyroid-stimulating hormone (TSH) levels with free thyroxine (fT4) estimates within the reference range. It is a common disorder that increases with age affecting up to 20% of the elderly, with a higher prevalence in women. S...

The hepatic enzyme 5β-reductase (AKR1D1) sits at the interface between two metabolic pathways, converting steroid hormones to their inactive 5β-reduced metabolites during steroid clearance, and as a step in the synthesis of bile acids from cholesterol. Both the steroid substrates and the bile acid products of AKR1D1 are potent hormones that regulate hepatic energy metabolism and inflammation. It is not known how these two functions are spatially organised within hepa...

Dysbiosis of the gut microbiome contributes to the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Reduced diversity and composition of the microbiome are associated with increased intestinal barrier permeability, increased bacterial translocation and NAFLD progression. The ALIOS diet in rodents replicates many of the metabolic and histological features of NAFLD in humans and here we report the effect of the ALIOS diet on the gut microbiome. Male and female C57BL/6 ...

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome, ranging from simple steatosis to the necro-inflammatory disease, non-alcoholic steatohepatitis (NASH). Development of NASH subsequently increases risk of hepatocellular carcinomas (HCC). Alongside the impact on the liver, NASH is associated with other clinical features, including insulin resistance, hyperlipidaemia and sarcopaenia. We demonstrate that mice fed the American lifestyle i...

Polycystic ovary syndrome (PCOS) is a clinical triad of anovulation, hyperinsulinaemia, and androgen excess. Adipose androgen generation of testosterone from androstenedione by aldo-ketoreductase type 1C3 (AKR1C3) may contribute to hyperandrogenism. We hypothesised that insulin may upregulate adipose AKR1C3 expression in vitro in a human differentiated preadipocyte cell line.We analysed AKR1C3 expression in the SGBS human preadipocyte cell line....

Polycystic ovary syndrome (PCOS) is a clinical triad of anovulation, insulin resistance, and androgen excess in women. Adipose androgen generation of testosterone from androstenedione by aldo-ketoreductase type 1C3 (AKR1C3) may contribute to hyperandrogenism, particularly in the setting of obesity. We aimed to determine the effects of BMI and age on AKR1C3 expression in subcutaneous (SC) and omental (OM) fat depots in both women and men.Paired SC and OM ...

Patients with glucocorticoids (GC) excess develop central obesity, insulin resistance and hepatic steatosis in up to 20% of cases. Current dogma suggests that GCs cause insulin resistance in all tissues. However, we have previously demonstrated that GCs induce insulin sensitisation in adipose tissue in vitro, whilst causing insulin resistance in skeletal muscle. In rodent hepatocytes, GCs enhance insulin stimulated lipogenesis but studies in human hepatocytes have not...

The potent effects of glucocorticoids (GCs) upon carbohydrate metabolism are well described. However, their actions upon lipid metabolism are poorly characterized. Patients with GC excess (Cushing’s syndrome) develop central obesity, insulin resistance and hepatic steatosis in up to 20% of cases. The A-ring reductases (5α-reductase type 1 [5αR1] and type 2 [5αR2]), inactivate cortisol as well as generate dihydrotestosterone (DHT) from testosterone (T) and a...

Glucocorticoid excess is characterized by increased adiposity, skeletal myopathy and insulin resistance. Although there is a strong inverse correlation between intramuscular triglyceride (IMTG) levels and insulin sensitivity, the impact of glucocorticoids upon the processes that regulate skeletal muscle lipid metabolism has not been explored.Mouse C2C12 skeletal myocytes were grown to confluence and differentiated into myotubes in chemically defined medi...