Endocrine Abstracts

The ability of the thyroid to accumulate iodide provides the basis for radioiodine ablation of differentiated thyroid cancers and their metastases. Most differentiated thyroid tumours exhibit reduced iodide uptake, however, and the mechanisms accounting for this remain poorly understood. Pituitary tumor transforming gene (PTTG) is a proto-oncogene implicated in the pathogenesis of thyroid tumours. We recently reported that PTTG and its binding factor PBF, also a potent transfo...

Differentiation between non functioning pituitary macroadenomas (NFPA) and prolactinomas may be difficult as hyperprolactinaemia can also be present at diagnosis in NFPA cases due to pituitary stalk compression (disconnection hyperprolactinaemia). Some authors suggested that prolactin >2,000 mIU/l is almost diagnostic of a prolactinoma, while others use a higher cut-off of >5000 mIU/l. Our aim was to identify the level of prolactin above which a prolactinoma was more l...

Studies on the probability of recurrence of surgically treated but radiotherapy (RT) naïve non-functioning pituitary adenomas (NFPA) are inconsistent and selective as cases deemed to be at high risk of recurrence were prophylactically irradiated. We traditionally used very low rate of post-operative RT leaving us with a largely unselected cohort.We identified 223 surgically resected, histology-proven NFPA cases. Only 9% received post-operative RT an...

The propensity for prolactin (PRL) to form high molecular mass complexes in serum is well described. Macroprolactin (mPRL), a PRL-immunoglobulin complex (>100 kDa), is the predominant form of PRL in up to 20% of patients with hyperprolactinaemia. Big PRL (bPRL, 40–50 kDa) is a ubiquitous, minor component of serum PRL rarely the major immunoreactive form, the nature of which is unclear. Using gel filtration chromatography (GFC) we have investigated the relative abundan...

Glucocorticoid (GC) excess is characterized by increased adiposity, skeletal myopathy and insulin resistance. Despite the increasing use of GCs as therapeutic agents, the molecular mechanisms that underpin GC mediated changes in insulin signalling are not clear. Within skeletal muscle, the microsomal enzyme, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) converts inactive GC, 11-dehydrocorticosterone (A) to active corticosterone (B) and thus regulates GC availabi...

Serum thyroglobulin (Tg) is a tumour marker used to manage patients with differentiated thyroid carcinoma (DTC). However, its diagnostic accuracy can be questioned when thyroglobulin antibodies (TgAb) are simultaneously present. Changes in serum TgAb can also serve as an index of disease progression in DTC. The objective of this study was to identify the relationship between TgAb titre and disease progression, defined as radiological or histological evidence of recurrence. Eig...

Autoimmune thyroid diseases (AITD), Graves’ disease (GD) and Hashimoto’s thyroiditis (HT) are common, but there is limited information on the prevalence of co-existing auto-immune diseases (AID). We prospectively collected 3309 patients with AITD and determined prevalences of other autoimmune diseases in index cases and relatives. Overall, 10.3% of 2806 GD patients and 18.1% of 503 HT subjects reported a co-existing AID. Rheumatoid arthritis was the commonest AID in ...

A retrospective analysis of the results of all intra-arterial calcium stimulations performed at St. Vincent’s Hospital, Dublin, in the years 2001-2006. All patients with symptoms suggestive of hypoglycemia had 72 hour fasting test with evidence of inappropriately elevated insulin and c-peptide at the time of hypoglycemia. These patients were investigated further with pancreatic imaging and selective intra-arterial calcium stimulation with hepatic venous sampling (ASVS). A...

Background: Proopiomelanocortin gene (POMC) and its cleaved product adrenocorticotrophin hormone (ACTH) play an important role in regulation of the hypothalamo-pituitary-adrenal (HPA) axis. ACTH stimulates the adrenal glands to release glucocorticoids. Glucocorticoid has a suppressive effect on ACTH and POMC. This suppression remains long after withdrawal, and may lead to adrenocortical insufficiency. POMC expression is dependent on the activities of some of the positively act...

Thyroid hormones play vital roles in fetal brain development. Mutations in MCT8, recently recognised as a specific thyroid hormone transporter, define a novel syndrome of severe X-linked psychomotor retardation and thyroid hormone resistance.N-TERA-2 (NT2) cells (human embryonal cells with characteristics of CNS precursors) were transiently transfected with either WT MCT8 or its L471P, R271H or S448X mutations, described in males affected by severe psych...