Endocrine Abstracts

The role of endogenous glucocorticoid (GC) production and metabolism in the pathogenesis of obesity, insulin resistance and type 2 diabetes remains unclear. Patients with Cushing’s syndrome develop central obesity, insulin resistance and in some cases type 2 diabetes (T2DM), yet circulating cortisol levels are not elevated in simple obesity. Alterations in GC metabolism, including 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) that generates active cortisol ...

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) converts inactive glucocorticoid to their active form (cortisone to cortisol in humans, 11-dehydrocorticosterone (11-DHC) to corticosterone in mice), and is dependent upon the presence of cofactor NADPH generated by the enzyme hexose-6-phosphate (H6PDH) for its activity. The 11β-HSD1/H6PDH system is implicated in the pathogenesis of the metabolic syndrome by generating tissue specific glucocorticoid excess. The ...

The epidemic of obesity, insulin resistance and type 2 diabetes has heightened the need to understand the mechanisms that contribute to their pathogenesis. Endogenous glucocorticoid (GC) production and metabolism have been implicated based upon parallels with Cushing’s syndrome. The interaction between GC metabolism and insulin sensitivity in the context of significant weight loss has not been explored. 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) that gen...

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...

Glucocorticoid (GC) production rates are elevated in obese, insulin resistant individuals. We and others have demonstrated decreased hepatic cortisol regeneration through reduced 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity that converts inactive cortisone to cortisol. In addition, there is enhanced cortisol clearance by A-ring reductases, (notably 5α-reductase). We have argued that these changes drive the hypothalamo-pituitary–adrenal axis a...

In peripheral target tissues, levels of active glucocorticoid hormones are controlled by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) which catalyses the reduction of cortisone to cortisol within the endoplasmic reticulum. For functional 11-ketoreductase activity, 11β-HSD1 requires the NADPH-generating enzyme hexose-6-phosphate dehydrogenase (H6PDH). Loss of 11-ketoreductase activity results in increased cortisol clearance and activation of the HPA axis wi...

Androgen excess is a key feature of polycystic ovarian syndrome (PCOS). Pre-receptor regulation contributes to this with increased activation of testosterone (T) to 5α-dihydrotesterone (DHT) by 5α-reductase type 1 (SRD5A1), as we have shown previously in PCOS (Lancet 1990,335:431; JCE&M 2003,88:2760). Peripheral blood mononuclear cells (PBMCs) are easily accessible and a useful model for studying pre-receptor regulation in the immune compartment. We have previous...

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic disease. Steroid hormones and bile acids are established regulators of metabolic phenotype. 5β-reductase (AKR1D1) is highly expressed in human liver where it inactivates steroid hormones and catalyzes a fundamental step in bile acid synthesis. We hypothesized that AKR1D1 plays a key role in hepatic metabolic homeostasis. Genetic manipulation of AKR1D1 ...

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic disease. Steroid hormones and bile acids are established regulators of metabolic phenotype. 5β-reductase (AKR1D1) is highly expressed in human liver where it inactivates steroid hormones and catalyzes a fundamental step in bile acid synthesis. We hypothesized that AKR1D1 plays a key role in hepatic metabolic homeostasis. Genetic manipulation of AKR1D1 ...

Increased adiposity is associated with insulin resistance, type 2 diabetes and metabolic dysfunction. Altered adipokine secretion, changes in local and systemic glucocorticoid metabolism and increased inflammation have all been postulated as contributory mechanisms. We have previously described changes in subcutaneous adipose tissue (SAT) gene expression that are associated with obesity and glucose intolerance in cross-sectional studies. However, the effects of longitudinal ch...