Endocrine Abstracts

INTRODUCTIONThe plasma concentrations and urinary excretion rates of 18-OH-F and 18-oxo-F are high in Conn's syndrome and glucocorticoid suppressible hyperaldosteronism, reputedly because aldosterone synthase (AS) has abnormal access to cortisol (F). However, both compounds are also excreted in normal subjects. Two enzymes, 11beta-hydroxylase (11OH) and AS, located in the zona fasiculata (ZF) and zona glomerulosa (ZG) respectively, are capable of 18-hydroxylation but only ...

We report the case of a 26 year old man who presented to his GP with infertility; biochemical investigations revealed elevated serum free thyroid hormones (FT4 41 pmol/l (12–22); FT3 13.4 pmol/l (2.8–7.1); and a normal TSH (2 pmol/l (0.27–4.2). He was referred to the endocrine department.On examination, he was found to be clinically well though thin (BMI 18), anxious and tremulous. His heart rate was 110 bpm and blood pressure was normal. ...

We report the case of a 53 year old woman with a history of refractory focal epilepsy with complex partial and secondary generalised seizures. She has been on multiple anti-epileptic drugs since childhood. At 42 years of age she was referred to the Endocrinology Department complaining of capital hair loss and hirsutism. At this time her epilepsy was controlled on phenytoin and carbamazepine.A diagnosis of congenital adrenal hyperplasia (CAH) was made, wi...

Annexin-1 (Anx-1), a 37 kDa protein, is a member of the super-family of Ca2+and phospholipid-binding annexin proteins and acts as a mediator of glucocorticoid (GC) action in the host defence and neuroendocrine systems. In the anterior pituitary Anx-1 is expressed mainly by folliculostellate (FS) cells and mediates the early-delayed feedback inhibition exerted by GCs on the release of ACTH and other pituitary hormones.The stress responsiveness ...

Annexin-1 (Anx-1), a 37kDa protein, is a member of the super-family of Ca2+- and phospholipid-binding annexin proteins and acts as a mediator of glucocorticoid (GC) action in the host defence and neuroendocrine systems. In the anterior pituitary Anx-1 is expressed mainly by folliculostellate (FS) cells and mediates the early delayed feedback inhibition exerted by GCs on the release of ACTH and other pituitary hormones.The role of Anx-1 in the ...

It has been noted that there are differences in the hypothalamic-pituitary-adrenal (HPA) axis between the sexes, as well as changes in the axis with age. The differences in the HPA axis between the gender and age groups are thought to be due to differences in the efficiency of glucocorticoid (GC) negative feedback. The pituitary, a principle site of GC negative feedback, is the focus of this investigation. Annexin-1 (ANXA1) is a member of the annexin family of phospholipid- an...

A 33 year old male was referred with poorly controlled hypertension. He gave no other past medical or family history. Despite therapy with multiple agents blood pressure was poorly controlled at 200/130 mm/Hg. Initial investigations which included renal ultrasound, magnetic resonance angiography and urine catecholamine excretion were all negative. Plasma renin concentration was suppressed (1 mu/ml/L, normal range 5 to 50) and plasma aldosterone was raised at 650 pmol/L (normal...

The key enzymes in the terminal stages of human adrenal gland corticosteroid biosynthesis are aldosterone synthase (AS) and 11-beta hydroxylase (11beta-OHase). Their amino acid sequences differ by only 7% but they exhibit markedly different enzymatic activities. AS is expressed solely in the zona glomerulosa and converts 11-deoxycorticosterone (DOC) to aldosterone whereas 11beta-OHase is expressed mainly in the zona fasciculata and produces cortisol from 11-deoxycortisol. The ...

The key enzymes in the terminal stages of human adrenal gland corticosteroid biosynthesis are aldosterone synthase (AS) and 11beta-hydroxylase (11beta-OHase). Their amino acid sequences differ by only 7% but they exhibit markedly different enzymatic activities. AS is expressed solely in the zona glomerulosa and converts 11-deoxycorticosterone (DOC) to aldosterone whereas 11beta-OHase is expressed mainly in the zona fasciculata and produces cortisol from 11-deoxycortisol. The 3...

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...