Endocrine Abstracts

Introduction: Glucocorticoids are vital for regulating metabolic processes, as well as use in medical treatments. However chronic glucocorticoid excess is known to cause negative metabolic effects including hyperglycaemia, muscle atrophy and fat accumulation. The effect on energy metabolism and metabolic rate remains undefined and merits investigation in both male and female mice.Methods: 20 male and 20 female C57BL/6J mice were randomly assigned to a co...

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...

Glucocorticoids (GC) have potent actions upon human adipose tissue, promoting adipocyte differentiation, inhibiting preadipocyte proliferation and inducing lipolysis to generate free fatty acids (FFA) and glycerol through a putative action upon hormone sensitive lipase (HSL). FFA have been strongly implicated in the pathogenesis of insulin resistance, yet the molecular mechanisms that cause GC induced lipolysis are not clear. Recently, several novel lipases have been identifie...

Introduction: Glucocorticoid excess (GE) causes severe metabolic dysfunction within skeletal muscle (SM) which includes reduced muscle accrual and increased proteolysis. The NAD+ metabolome is crucial for SM health and metabolic function, however, whether this is disrupted by GE remains unknown.Methods: Male and female C57BL/6J mice (n=12) were treated with a vehicle control or corticosterone (100 mg/l) ad libitum via drinking water for 3 weeks ...

Glucocorticoids (GC) are critical to stress adaptation but in excess (Cushing’s syndrome) drive metabolic dysfunction. 11β-hydroxysteroid dehydrogenase type 1(11β-HSD1) amplifies intracellular GC signaling with 11β-HSD1KO mice protected from the side-effects of GC excess. Brown adipose tissue (BAT) function is impaired by GC’s, which repress UCP1 and beta-adrenergic stimulated thermogenesis. Identifying mechanisms regulating BAT function is important a...

Introduction: There is growing evidence that 11β-HSD1 expression/activity increases with age in key target tissues including adipose tissue, bone, and skin, implicating local amplification of glucocorticoids in the pathophysiology of related disease. We have previously shown that 11β-HSD1KO mice are protected from both the adverse metabolic effects of excess glucocorticoids and age-associated muscle weakness. We investigated changes in global activity and skeletal mu...

The primary function of brown adipose tissue (BAT) is to use lipids to generate heat through uncoupling of oxidative phosphorylation in mitochondria. Glucocorticoids (GC) have a negative effect upon BAT through inhibition of uncoupling protein 1 (UCP1) expression. Similarly, it has been reported that BAT levels decline with age and have been linked to age related accumulation of body fat, leading to the idea that improving BAT function during ageing could have a beneficial rol...

Glucocorticoids (GCs) are prescribed for their anti-inflammatory and immunosuppressive properties. However, they have significant side-effects including a decline in muscle mass and function which has similarities to age related sacropaenia. Within skeletal muscle 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) converts 11-dehydrocorticosterone (11DHC) to active corticosterone (CORT) amplifying local GC action. We hypothesise that 11β-HSD1 mediated intramyoce...

The pathophysiological effects of glucocorticoid (GC) excess (Cushing’s syndrome) are similar to the aging phenotype. As such, we hypothesise that age-related changed in body composition (central obesity, reduced bone density, reduced muscle mass and skin thinning), and resultant chronic disease (type 2 diabetes, osteoporosis, sarcopenia and heart disease) may be caused by increased GC exposure with age. However, circulating GC’s show little change with advancing age...

Intra-abdominal adiposity is associated with insulin resistance and increased cardiovascular morbidity and mortality. Consequently, there is a need to identify factors involved in adipose tissue distribution. Patients with glucocorticoid (GC) excess develop a classic phenotype characterized by central, but not peripheral, obesity. Differences in gene expression between omental (om) and subcutaneous (sc) adipose tissue have been described, however, the molecular mechanisms unde...