Endocrine Abstracts

Adult Growth Hormone Deficiency (AGHD) is associated with osteoporosis. PTH circadian rhythmicity is important for bone remodelling. Abnormalities in PTH circadian rhythms, including a blunted nocturnal rise, have been reported in AGHD and may contribute to osteoporosis development. GH replacement (GHR) results in improvement of PTH circadian rhythmicity and bone mineral density (BMD). In health, increasing age is associated with declining GH secretion and the appropriateness ...

Alterations in PTH circadian rhythmicity have previously been reported in Adult Growth Hormone Deficiency (AGHD) and may contribute to the pathogenesis of AGHD-related osteoporosis. However, changes in PTH circadian rhythm have not been correlated with bone mineral density (BMD) in AGHD. Serum phosphate is a likely determinant of PTH rhythm. We examined the PTH and phosphate circadian rhythms in AGHD patients with reduced (defined as femoral neck T-score <-1.0) and normal B...

Growth hormone (GH) and leptin regulate body composition and leptin is elevated in adult growth hormone deficiency (AGHD), a syndrome characterised by increased adiposity. We have previously shown that GH replacement for 1 month reduces 24-h mean leptin concentration independent of changes in fat mass. The long tem effects of GHR on leptin have not been described.24-h mean total leptin concentration was measured using half-hourly blood sampling, to accou...

18-hydroxycortisol (18-OHF) and 18-oxocortisol (18oxo-F) are derivatives of cortisol whose origin and regulation are uncertain. 18-OHF is synthesised by zona fasciculata 11-beta hydroxylase; 18-oxoF can only be produced by zona glomerulosa aldosterone synthase. Levels of both steroids are increased in patients with Primary Aldosteronism. However, the origin of these steroids in normal subjects is not known.8 normal subjects and 6 subjects with primary adrenal failure performed...

11Beta-Hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) catalyse the synthesis of corticosterone and aldosterone respectively in the rat adrenal cortex. Recent studies have shown that CYP11B1 and CYP11B2 are also expressed in the central nervous system (CNS) but little is known about their regulation. In this study, we have quantified CYP11B1 and CYP11B2 gene expression in the CNS following treatment with ACTH and dexamethasone.Three groups of ma...

11Beta-Hydroxylase and aldosterone synthase catalyse the synthesis of corticosterone and aldosterone in the rat adrenal cortex and are encoded by the CYP11B1 and CYP11B2 genes respectively. These genes are also expressed in distinct regions of the CNS and cardiovascular system where they may play a key role in behavioural response and blood pressure homeostasis. However, it is unclear whether this extra-adrenal expression is regulated by, or contributes to, circulating levels ...

BACKGROUND: Acromegaly is associated with abnormal bone metabolism, characterized by increased bone turnover. In health, PTH is secreted in a circadian rhythm, which is important in bone function. However, the effect of acromegaly on PTH secretion is unclear, with previous studies reporting increased, decreased or no change in PTH concentration. Furthermore, the presence of PTH circadian rhythmicity has not been defined in acromegaly.OBJECTIVES: To determine the effect of ...

BACKGROUND: AGHD is associated with increased prevalence of osteoporosis. Alterations in both parathyroid gland sensitivity to changes in calcium concentration and end-organ response to the effects of PTH play a role in the development of osteoporosis.OBJECTIVES: To investigate the effects of PTH (1-34) infusion on end-organ and parathyroid gland responsiveness.METHODS: 6 patients with severe AGHD were recruited. All patients were admitted, prior to commencement of GH ...

BACKGROUND: AGHD is associated with reduced BMD. GHR results in improvement in BMD, however, some patients remain osteopaenic despite all appropriate pituitary hormone replacement. PTH plays an important role in bone metabolism, with anabolic effects following intermittent administration. To date the difference in PTH activity and phosphocalcium metabolism between fully replaced AGHD patients with normal and reduced BMD has not been investigated.OBJECTIVES: To determine th...

BACKGROUND: AGHD is associated with osteoporosis. Alterations in parathyroid gland responsiveness to changes in calcium concentration play a role in the genesis of osteoporosis.OBJECTIVES: To investigate PTH response to hypo- and hypercalcaemic stimuli in AGHD.METHODS: 12 patients with untreated AGHD were consented to the study. Venous cannulae were inserted in each arm and half-hourly blood samples collected between 0900-1800hours for PTH, calcium and albumin. After 5...