Endocrine Abstracts

Introduction: The beneficial effect of GH replacement on bone in AGHD patients is mediated by improvements in target organ sensitivity to PTH and phosphocalcium metabolism. In aging women with established osteoporosis, GH and IGF-1 concentrations are lower and administration of GH has been shown to increase bone turnover and BMD, but the mechanisms remain unclear.Methods: Fourteen postmenopausal women (63.4±2.1 years; mean BMD T score ± ...

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...

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 ...

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...

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...

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 ...