Endocrine Abstracts

Essential hypertension is known to have a large genetic component. Variation in the CYP11B2 gene, which encodes the aldosterone synthase enzyme, is associated with excess aldosterone production and hypertension but the causative mechanism remains elusive. miRNAs are a class of post-transcriptional regulatory molecules, implicated in cardiovascular disease, development and tumourogenesis. They act by targeting the 3′ untranslated region (UTR) of mRNAs, inhibiting t...

Aim: In chronic kidney disease (CKD) elevated aldosterone (Aldo) levels are a poor prognostic indicator, particularly in the context of a high dietary sodium intake, through unclear mechanisms. Blockade of the mineralocorticoid receptor (MR) improves surrogate patient outcomes. We hypothesised that regulation of aldosterone biosynthesis is disordered in CKD and aimed to compare this in a cohort of patients with CKD with subjects with essential hypertension (EH).<p class="a...

The CYP11B1 and CYP11B2 genes encode 11β-hydroxylase and aldosterone synthase, which catalyse the production of cortisol and aldosterone, respectively, and have been implicated in the development of hypertension. For this study, we wished to investigate the role of microRNAs (miRNAs), a novel class of post-transcriptional gene regulators. To that end, we generated a profile of human adrenal miRNAs to study, and then investigated the action of one adrenal miR...

Previous studies investigating steroidogenic enzymes in the brain have often focused on only a few genes at a time, using animal models or pooled human RNA to investigate their expression. For this study, we obtained RNA from individual archived human brain tissue samples in order to analyse the transcription of twelve genes involved with steroid biosynthesis and metabolism within the cerebellum and hippocampus.We developed realtime RT-PCR assays for twe...

Background: Aldosterone levels in plasma are reported to be associated with risk of hypertension. Aldosterone secretion from the zona glomerulosa is regulated acutely by the renin/angiotensin system and plasma potassium. The role of ACTH in regulation of aldosterone secretion is disputed.Aim: We have utilised a large population study of middle aged adults to test the extent to which acute aldosterone responses to ACTH are associated with cortisol respons...

Aldosterone is key in the development of hypertension. We have shown that a SNP (−344T) in the 5’ regulatory region (UTR) of the gene encoding aldosterone synthase (CYP11B2) was associated with aldosterone excess and high blood pressure. However, the most robust phenotype is altered adrenal 11-hydroxylation efficiency (deoxycortisol to cortisol); a step carried out by 11β-hydroxylase, encoded by the adjacent gene, CYP11B1. We proposed that the effects of CYP11B...

(This poster is based on OC19)...

Recent genome-wide association studies (GWAS) implicate the CYP17A1 locus in human blood pressure regulation. This gene is important in steroidogenesis, regulating both glucocorticoid and androgen synthesis through catalysis of 17α-hydroxylation and 17,20 lyase reactions. We hypothesised that functional CYP17A1 polymorphisms linked to those identified by GWAS influence blood pressure levels. We therefore screened the entire CYP17A1 locus by dire...

Background: Primary Aldosteronism (PA) is common and associates with excess cardiovascular morbidity independent of blood pressure. Animal and in vitro studies have demonstrated that exposure to aldosterone and sodium leads to cardiac fibrosis and hypertrophy and this may, partly, be mediated by inflammation and oxidative stress. We aimed to clarify the effects of aldosterone excess on myocardial structure and composition in humans using contrast-enhanced cardiac MRI as well a...

Aim: Increasing left ventricular mass index (LVMI) is associated with a poor prognosis in patients with chronic kidney disease (CKD). Blockade of the mineralocorticoid receptor (MR) in CKD leads to improvement in proteinuria and LV mass. However, the MR can be activated by aldosterone, cortisol and deoxycorticosterone (DOC) and their relative contribution to adverse events in CKD is unclear. We aimed to assess the correlation between mineralocorticoid excretion and LVMI in pat...