Endocrine Abstracts

WNK1 and WNK4 are serine/threonine kinases, With-No-K (lysine) residue at a key catalytic position within the active site. Mutations in either cause Pseudohypoaldosteronism type II (Gordon syndrome), an autosomal dominant, hypertensive, hyperkalaemic disorder, especially responsive to thiazide diuretics (first line treatment for essential hypertension). This novel WNK pathway is implicated in normal regulation of blood pressure (BP) and distal nephron Na+/K+</s...

Adverse events in utero permanently alter the structure and physiology of adult offspring, a phenomenon termed 'foetal programming'. In particular, low birth-weight is associated with an increased risk of adulthood hypertension. Glucocorticoid (GC) administration during pregnancy reduces offspring birth-weight and GCs directly elevate blood pressure (BP) in both humans and rodents. Circulating and local renin-angiotensin-aldosterone (RAAS) system(s) may be involved in programm...

Renal functions in a mouse model of Cushing’s Syndrome have been characterised by analysing RNA expression complemented by immunohistochemistry studies. A microarray of kidneys from mice infused with ACTH for two weeks identified gene transcripts that were up-regulated (70) and down-regulated (49) more than two-fold. Four separate clusters of closely correlated genes (r> 0.97; P< 0.001) were investigated in more detail. One down-regulated cluster included histocom...

Introduction: Humans with glucocorticoid receptor (GR) deficiency and global heterozygous GR knockout (GR+/−) show compensatory activation of the hypothalamic-pituitary-adrenal axis, resulting in salt-sensitive hypertension due to increased mineralocorticoid activity. Previous studies suggest renal mechanisms, including changes in cell proliferation, gene expression and electrolyte transport, may contribute to this phenotype but underlying adaptive adrenal responses have...

Background and aims: Bile acids are conserved through enterohepatic circulation, a glucocorticoid-modulated process. 11β-Hydroxysteroid dehydrogenase type-1 (11β-HSD1) converts cortisone/11-dehydrocortisone to cortisol/corticosterone, thus increasing intracellular glucocorticoid levels. 11β-HSD1 also metabolises 7-oxo-lithocholic acid, a bile acid. 11β-HSD1 is highly expressed in the liver and may alter bile acid transport through regeneration of active glu...

Background: The effects of glucocorticoids (GC) on the developing zebrafish embryo (Zfe) are poorly characterised. We have assessed the effects of pharmacological and genetic manipulation of cortisol and glucocorticoid receptors (GR) on global development and stress response during the first 120 hpf.Methods: Cortisol production was modulated by inhibiting the enzyme 11b hydroxylase using morpholino gene knockdown (MO) or incubation in the drug metyrapone...

Variation in the glucocorticoid receptor (GR) gene associates with relative glucocorticoid resistance, hypertension and increased cardiovascular disease risk in humans. To investigate the contribution of cardiac GR to this phenotype we have characterised adult male mice with cardiomyocyte and vascular smooth muscle deletion of GR (SMGRKO) and have found left ventricular function to be impaired.SMGRKO mice, generated by crossing GR ‘floxed’ mice...

Glucocorticoid signalling is essential for cardiac maturation late gestation. In mice, global glucocorticoid receptor deficiency (GR−/−) severely impairs cardiac function and ultrastructure at embryonic day (E) 17.5. To dissect direct effects of GR deficiency in the heart from effects on other systems, Sm22α-Cre mice were crossed with ‘floxed’ GR mice to generate SMGRKO mice with disrupted GR signalling in cardiomyocytes and vascular smoot...

11β-Hydroxysteroid dehydrogenase type one (11β-HSD1) converts inert glucocorticoids to active forms, amplifying intracellular glucocorticoid action. 11β-HSD1 also catalyses the reduction of seven-ketocholesterol (7KC) to 7β-hydroxycholesterol (7βHC). 7KC may inhibit cholesterol biosynthesis (Brown et al. 2002). Alteration of cholesterol homeostasis is a major atherosclerotic risk factor. 11β-HSD1 deficiency/inhibition is atheroprotective ...

Background and aims: Bile acids regulate cholesterol metabolism and the digestive system. They are conserved through enterohepatic circulation, a glucocorticoid-modulated process. We investigated whether the regeneration of active glucocorticoid by 11β-hydroxysteroid dehydrogenase type one (11β-HSD1) affects bile acid release and enterohepatic transport after re-feeding.Methods: Bile acid turnover was assessed in global (Hsd11b11<...