Endocrine Abstracts

Background: Thyrotropinomas (TSHomas) are traditionally considered a rare albeit important cause of thyrotoxicosis, accounting for ∼1% of all pituitary adenomas. Although early case series reported a preponderance of macroadenomas, emerging evidence suggests microadenomas are being increasingly diagnosed. In addition, the clinical/biochemical phenotype appears to be more variable than previously suspected. We therefore examined the clinical, metabolic, biochemical and ra...

Resistance to thyroid hormone (RTH) is usually due to heterozygous mutations in THRB gene with rare cases being homozygous for receptor defects. We describe an RTH case due to a homozygous TRβ mutation (R243Q).The Proband (male, 8.4 years), was born at term with low birth weight (1.9 kg) to consanguineous parents. He has a prominent nasal bridge, goitre, low body weight (10th centile), recurrent tonsillitis, hyperactivity and has mild hearing impair...

Background: The recently published ‘Consensus on Criteria for Cure of Acromegaly’ (Giustina et al. JCEM, 2010) highlighted concerns regarding the quality of currently available insulin-like growth factor 1 (IGF1) immunoassays which may contribute, at least in part, to the discordance between GH and IGF1 that is observed in up to 30% of patients with acromegaly after treatment. The development of mass spectroscopy (MS)-based technology has been proposed ...

As thyroglobulin antibodies (TgAb) are a well recognised cause of interference in thyroglobulin (Tg) immunoassays current guidelines recommend that TgAb should be measured concurrently with Tg when monitoring thyroidectomised thyroid cancer patients. However the concordance between different TgAb assays has been questioned despite the availability of an International TgAb Reference Preparation (MRC 65/93).Four commonly used TgAb assays were tested in 145...

Metyrapone (MT) is used in the medical management of Cushing’s syndrome as it decreases serum cortisol (CT) levels by inhibiting adrenal β-hydroxylation of 11-deoxycortisol, the final step in CT synthesis. CT precursors, in particular 11-deoxycortisol (DOC), increase following MT therapy. Monitoring glucocorticoid replacement in patients taking MT could therefore be confounded as DOC cross-reacts in commonly used immunoassays (IA) for serum CT. Serum CT results from ...

We report five cases of hyperthyroidism with complex management issues, which were successfully treated with iopanoic acid prior to thyroidectomy.Three patients (cases 1–3) had Graves’ disease; two developed agranulocytosis on carbimazole and one had uncontrolled severe thyrotoxicosis and poor compliance with treatment. Radioiodine was either declined or contraindicated due to radio-protection issues. All patients were rendered euthyroid with i...

TSH secreting tumours (TSH-omas) are uncommon, accounting for less than 2% of pituitary tumours. Typically, patients with such tumours demonstrate hyperthyroidism with detectable or elevated TSH levels, and show little response to TRH stimulation. Treatment is controversial: typically surgery, radiotherapy or somatostatin analogues.We present a 22 year-old man who was found to be tachycardic on joining a gym in 2003. There were no other symptoms or signs...

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...

The differential diagnosis of raised circulating thyroid hormones with normal TSH includes familial dysalbuminaemic hyperthyroxinaemia (FDH), a benign, inherited disorder caused by a variant albumin with increased affinity for thyroxine (T4) or triiodothyronine (T3). Three different albumin gene mutations, generating mutant proteins with increased affinity for either T4 (R218H,R218P) or T3 (L66P) have been commonly described. Typically, serum total T4 is raised and free T4 mea...

Beta-cell function of HIV-infected patients on highly active antiretroviral therapy (HAART), who display lipodystrophy, may be impaired. An early defect in beta-cell function may be characterized by an increased secretion of 32–33 split proinsulin (SP) and intact proinsulin (IP).To address this issue the secretion pattern of SP and IP of 16 HIV-infected men with lipodystrophy (LIPO) and 15 HIV-infected men without lipodystrophy (NONLIPO) were studie...