Endocrine Abstracts

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...

Background: The CYP11B1 (11β-hydroxylase) and CYP11B2 (aldosterone synthase) genes are found in close proximity on human chromosome 8 and are highly polymorphic, enabling the definition of two common haplotypes. Haplotype1 includes the -344T and the Intron2 conversion polymorphisms in CYP11B2 and also the -1889T, -1859G polymorphisms in the regulatory region of CYP11B1. We and others have shown that these associate with increased aldosterone pr...

Aldosterone synthase (CYP11B2) and 11beta-hydroxylase (CYP11B1) genes are highly homologous in their coding regions (95%), lie in tandem approximately 40kb apart in human chromosome 8, and may have arisen from gene duplication. The pattern of linkage disequilibrium (LD) of this region in a population is determined not only by the distribution of recombination events but also by demographic factors determining the amount of random genetic drift. There is suggestiv...

The glucocorticoid receptor (GR) is a member of the nuclear hormone receptor superfamily that acts as a hormone responsive transcription factor. GR function is controlled by hormone binding, post-translational modifications and through interaction with cofactors. Here, we report that JNK dependent phosphorylation of GR affects its sumoylation. JNK activation by UV radiation that targets GR for phosphorylation at serine 246 (S246) facilitated subsequent GR sumoylation at lysine...

The corticosteroids aldosterone and cortisol are implicated in the aetiology of hypertension. The CYP11B1 and CYP11B2 genes encode 11β-hydroxlylase and aldosterone synthase; polymorphisms across the CYP11B1/B2 locus are associated with increased aldosterone production, inefficient 11β-hydroxlation and hypertension. While polymorphisms located in the promoter region of both genes may alter transcription factor binding, other variants located in th...

Background: Vitamin D3 is generated in the skin of humans from 7-dehydrocholesterol by ultraviolet light. Vitamin D3 is hydroxylated to its metabolically active form in the liver and kidneys. The hydroxylated form of Vitamin D3, is required for both phosphate and calcium absorption in the gut and reabsorption from the kidneys. Vitamin D deficiency is associated with a low circulating calcium and phosphate.Case report: A 5...

Background: Recent studies have indicated that macroprolactinaemia accounts for up to 26% of biochemical hyperprolactinaemia depending on the assay in use. Delayed metabolic clearance of macroprolactin together with detection by most automated prolactin immunoassay systems leads to pseudo-hyperprolactinemia in patients harbouring this form of complexed prolactin.We here describe the use of serial macroprolactin measurement to assist in the management of ...

Background: Virilising congenital adrenal hyperplasia (CAH) is the most common cause of genital ambiguity, and 90–95% of CAH cases are caused by 21-hydroxylase deficiency. Associated inefficient cortisol synthesis results in increased CRH and ACTH levels, leading to production of excess sex hormone precursors. These are further metabolized to active androgens and to a lesser extent oestrogens. We recently reported that one of these androgens, DHEA-S or its metabolites sig...

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...