Endocrine Abstracts

Background & Aims: Observational studies implicate glucocorticoid excess, principally due to altered steroid metabolism in target tissues, in both the insulin resistance and liver fat accumulation that accompanies type 2 diabetes. To test the contribution of glucocorticoid signalling to metabolic dysfunction we blocked cortisol secretion (with metyrapone) and action (with the GR antagonist mifepristone) simultaneously in men with type 2 diabetes ± fatty liver.<p c...

Background: Testosterone deficiency is common in obesity and in type 2 diabetes mellitus. It is hypothesised that the expanded adipose pool, which is the major source of aromatase in men, depletes testosterone levels by excess conversion to estradiol. Individuals with either the GG rs2470152 polymorphism in intron 1 or a high number of TTTA repeats in intron 4 of CYP19 are known to have greater aromatase activity with demonstrable effects upon plasma estradiol and osteoporosis...

Glucocorticoid (GC) excess, whether exogenously- or endogenously-derived, induces many adverse effects in skin including thinning, decreased cellularity and reduced collagen synthesis. Consequently, skin exhibits reduced dermal structural integrity, increased atrophy/fragility/bruising and impaired wound healing, effects that perfectly mimic skin ageing. Local GC levels are regulated in a tissue-specific manner by 11β-hydroxysteroid dehydrogenase (11β-HSD) isozymes i...

Inhibiting cortisol regeneration by 11β-HSD1 is a promising therapy for type two diabetes. In obesity, 11β-HSD1 activity is increased in adipose tissue but decreased in the liver, the latter putatively mediated by hyperinsulinaemia. We tested whether insulin sensitisation with metformin regulates 11β-HSD1 activity in whole body and in liver in obesity.Five obese men (age 48±5 years, BMI 39.8±3.6 kg/m2) participated in ...

Circulating estrogens decrease after the menopause from 60–400 to 5–30 pg/ml in postmenopausal women and in men are below 30 pg/ml. These low physiological concentrations present an analytical challenge. Analysis of steroids by tandem mass spectrometry is attractive due to its high specificity compared with immunoassays. However, estrogens do not ionise efficiently and therefore chemical modifications are necessary to achieve the sensitivity required.<p class="ab...

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...

The glucocorticoid hormone, cortisol, regulates fuel metabolism, inflammation and stress–responses. Its circulating concentrations are tightly controlled by the hypothalamic–pituitary–adrenal axis. However, 11β-hydroxysteroid dehydrogenase 1 (11βHSD1) generates additional cortisol in tissues, by reduction of inert cortisone. Using a tracer (9,11,12,12[2H]4-cortisol; d4-cortisol), the velocity of 11βHSD1 can be determined as t...

Inhibitors of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) are being developed to prevent cortisol regeneration from cortisone in liver and adipose tissue in type 2 diabetes (T2DM). However, the target patient group is uncertain. In obesity 11β-HSD1 activity is increased in adipose tissue but decreased in liver, as judged indirectly by plasma cortisol levels after oral cortisone administration. However, in T2DM, urinary steroid ratios suggest liver 11&#946...

Previously, we have shown that 5α-tetrahydrocorticosterone (5αTHB), the reduced metabolite of corticosterone (B, the main glucocorticoid in rodents), binds to the glucocorticoid receptor, suppresses the HPA axis but has weak in vivo effects on adipose tissue and liver metabolism. Here we have compared the anti-inflammatory effects of B and 5αTHB in three in vitro and in vivo experiments. Cytokine release was measured by cytometric bead array...

Background: Kisspeptin is a neuropeptide central to the regulation of gonadotrophin secretion but recent studies have suggested more diverse roles in human physiology. Kisspeptin is a potent inhibitor of tumour metastasis and plays a role in placentation, both processes involving angiogenesis. In addition, Kisspeptin and its receptor, GPR54, have been identified in human blood vessels including aorta, coronary artery and umbilical vein, where they mediate vasoconstriction. We,...