Endocrine Abstracts

Rhythmic, timed secretion of ghrelin and leptin is integral to the intricate temporal interplay of hormonal signals that maintains energy balance, feeding and body weight. Growth hormone replacement (GHR) in adult growth hormone deficient (AGHD) patients has been shown to alter body composition, energy balance and insulin sensitivity with changes in leptin secretory pattern and concentration. With GHR, single time point ghrelin concentrations have been shown to either increase...

The major glucocorticoids (cortisol in man and corticosterone in the rat) play an important role in obesity and its attendant hypertension. However, there is no consistent evidence of glucocorticoid excess in simple obesity, suggesting that its role in the regulation of adipose tissue mass results from a more complex mechanism than adrenal hypersecretion of glucocorticoid. Glucocorticoid biosynthesis is not limited to the adrenal cortex; mRNA and enzymatic activity of 11β...

Corticosteroids can be synthesised in tissues other than the adrenal cortex but the contribution of this extra-adrenal corticosteroidogenesis to circulating levels in man is not known. We studied this in a group 10 subjects taking chronic glucocorticoid replacement following bilateral adrenalectomy. In phase 1, they were maintained on cortisol alone (30 mg/day). In phase 2, cortisol was replaced by dexamethasone (2 mg/day) and in phase 3, they received both cortisol and dexame...

PTH plays an important role in bone metabolism. Active acromegaly is associated with increased bone turnover. Reduction in bone turnover markers occurs following biochemical cure/control of acromegaly. We examined the effect of active acromegaly and its treatment on PTH concentration and PTH target-organ sensitivity.10 patients with active acromegaly (defined as GH nadir greater than 1mU/L following 75g oral glucose load and IGF1 above reference range) a...

Adult Growth Hormone Deficiency (AGHD) is associated with relative phosphate deficiency. Phosphate is an important determinant of serum PTH concentration. PTH target-organ sensitivity is reduced in AGHD and may underlie the pathogenesis of AGHD-related osteopaenia. We examined the effect of phosphate supplementation on change in PTH target-organ sensitivity when given simultaneously with Growth Hormone Replacement (GHR) in AGHD patients.24 AGHD patients ...

Background: Untreated adult growth hormone deficiency (AGHD) is associated with hypertension, obesity and hyperleptinemia. Leptin is linked to obesity related hypertension, is secreted in a circadian rhythm and may contribute to the regulation of BP circadian rhythmicity.Methods: We studied the relationship between plasma leptin (half hourly samples), ambulatory systolic BP (SBP), diastolic BP (DBP) and mean arterial pressure (MAP) over a 24-h period in ...

We have shown that linked polymorphisms in the aldosterone synthase gene (CYP11B2) are associated with hypertension and altered aldosterone production. However, the most consistent intermediate phenotype associated with this genetic variation is increased plasma 11-deoxycortisol (S) and urinary excretion of its metabolite, tetrahydrodeoxycortisol (THS); this is paradoxical as S is a substrate for the enzyme 11beta-hydroxylase, encoded by the neighbouring gene, CYP11B1. However...

ObjectiveDoes subclinical hypothyroidism (SCH)cause increased cardiovascular risk and how does treatment affect cardiac and vascular function in patients with SCH?MethodsCardiac function and central arterial stiffness(CAS)were measured in 20 females (mean age 50.1 plus/minus 4.1 years)with SCH (mean free T4 12.2 plus/minus 0.2 picomol per litre [normal range 9.8-22.1],median TSH 8.8 milliunits per litre[norma...

BACKGROUND Human and animal evidence indicates that poor maternal nutrition leads to programmed endothelial dysfunction and hypertension in offspring. In humans, endothelial dysfunction has been observed in independent cohorts studied aged 7 and 11, but explanatory molecular mechanisms are lacking. Endothelial function, and synthesis of nitric oxide (NO) by endothelial nitric oxide synthase (eNOS), relies on nutrient supply of L-arginine, with maternal dietary restriction in r...

Leptin stimulates osteoblastic cell proliferation, differentiation and mineralisation and inhibits osteoclast generation; leptin secretion and bone turnover are altered in adult growth hormone deficiency, a condition associated with osteoporosis. The aim of this study was to investigate leptin circadian rhythm and its association with bone turnover in untreated AGHD and following growth hormone replacement (GHR).We sampled peripheral venous blood at half...