Endocrine Abstracts

Current therapeutics target cGMP in treating erectile dysfunction and other cardiovascular disorders. In the endocrine system, cGMP mediates the vast majority of biological effects of the natriuretic peptides (ANP, BNP and CNP) acting via their specific guanylyl cyclases receptors (GC-A and GC-B). There are severe endocrine consequences for mice and humans exhibiting mutations to GC-B receptors, including achondroplasia, growth hormone deficiency and female infertility. Despit...

CNP, the third member of the mammalian natriuretic peptide family, exerts the majority of its biological effects via the guanylyl cyclase B (GC-B) receptor, resulting in accumulation of intracellular cGMP. Previous studies reveal numerous inhibitory effects of natriuretic peptides on the MAPK family in bone, neuronal and cardiovascular tissues. However, we recently reported that CNP stimulates ERK, p38MAPK and JNK phosphorylation in pituitary GH3 somatotrophs. As CNP is known ...

The ubiquitous transcription factor, CREB, is responsible for mediating gene transcription in many endocrine tissues. Recent studies reveal that the activation of several signalling pathways can lead to the phosphorylation of CREB at Ser133, including PKC, MAPKs, CaMKs, and PI3K. In the pituitary gonadotroph, there are consensus cAMP response elements (CREs) in several of the gonadotrophin subunit promoters as well as in the GnRH receptor promoter. We have previously shown tha...

Adipsic diabetes insipidus (ADI) is a rare condition which has been reported following clipping of anterior communicating artery aneurysms, craniopharyngioma and brain trauma, but not with pituitary adenoma. We report a case of ADI following surgery for a pituitary macroprolactinoma. A 14-year-old boy presented with bitemporal hemianopia due to a large macroprolactinoma. Two debulking surgeries were performed without the development of diabetes insipidus. Following a third rad...

ObjectiveThere is large inter-individual variation in the growth hormone (GH) response to resistance exercise, but the intra-individual variation is unknown. This study aimed to determine the reproducibility of the GH response to a 30-min resistance exercise session.DesignFollowing local Ethics Committee approval, nine male participants were familiarised before completing three trials in a random order. Durin...

Hypopituitarism has been reported in 28-65% of long-term survivors of traumatic brain injury (TBI). We attempted to define the natural history of post-traumatic hypopituitarism in order to devise guidelines for the optimal timing of patient assessment and hormone replacement.Fifty consecutive patients with severe or moderate TBI were enrolled in a prospective study of pituitary function during the acute phase, at 6 months and, at 12 months following TBI....

The syndrome of inappropriate antidiuretic hormone (SIADH) is characterised by euvolamic hyponatraemia. Patients with SIADH continue to drink normal amounts of fluid, despite plasma osmolalities well below the physiological osmotic threshold for the onset of thirst. The regulation of thirst has not been previously studied in SIADH. We studied the characteristics of osmotically-stimulated thirst and vasopressin (AVP) secretion, and the non-osmotic suppression of thirst and AVP ...

Recent evidence suggests a high prevalence of neuroendocrine dysfunction in patients following traumatic brain injury (TBI), but dynamic anterior pituitary assessment were performed in relatively small number of patients and posterior pituitary function remains poorly investigated.We studied 102 consecutive patients (84 males) who had survived severe or moderate TBI [initial Glasgow Coma Scale (GCS) score 3-13] at a mean (+/- standard deviation) of 19 +/...

Hyperprolactinaemia in the presence of pituitary tumour can occur from tumour secretion or from stalk compression causing loss of dopaminergic inhibition. It is generally accepted that, in the presence of a large pituitary mass, a serum prolactin level up to 3000mU/l indicates stalk compression rather than a prolactinoma; the clinical diagnosis of prolactinoma depends on the degree of hyperprolactinaemia in the context of pituitary tumour size. Our aim was to examine more form...

Acromegalic patients have increased morbidity and mortality, which correlate with post-treatment growth hormone (GH) level. Target post-treatment plasma GH level should be less than 2.5 nanograms per millilitre, which predicts normal life expectancy.We evaluated the prevalence of complications and treatment outcome in 76 acromegalic subjects who attended our unit for surgery between 1978-2002. 60 patients are followed up in a specialised pituitary clinic in Beaumont Hospit...