Endocrine Abstracts

The type 3 deiodinase enzyme (D3) inactivates T3 and prevents activation of T4 to protect the fetus from premature exposure to thyroid hormones. Rapidly falling levels of D3 activity and rising levels of T3 at birth initiate the onset of cell differentiation and organ maturation during the post-natal period. Congenital hypothyroidism causes delayed ossification with reduced bone mineral deposition and short stature. We hypothesize that increase...

Similar to thyroid hormones, the calcineurin/NFAT pathway regulates bone mass via its actions in osteoblasts and by indirect effects on osteoclast function. Calcineurin is a calcium- and calmodulin-activated phosphatase that dephosphorylates the transcription factor NFAT enabling its translocation to the nucleus. RCAN2 is an inhibitor of calcineurin that is stimulated by T3 in brain, heart and skeletal muscle although its expression in bone has not been studied. Thu...

MEN2B is the most aggressive form of MEN2. Consequently, the new American Thyroid Association guidelines recommend prophylactic thyroidectomy early in the first year of life. Ninety-seven percentage of MEN2B cases result from a germline methionine to threonine mutation at codon 918 (M918T) of the RET proto-oncogene. In addition, an exceedingly rare alanine to phenylalanine mutation at codon 883 (A883F) has been reported in 4 unrelated adults. In each case metastatic MTC and th...

Background: The Endocrine Society clinical practice guidelines suggest use of the 1 mg overnight dexamethasone suppression test (ONDST) to screen for cortisol excess in patients with adrenal incidentalomas, followed by the 48-h, 2 mg/day, low-dose dexamethasone-suppression test (LDDST), to confirm a positive result. Visceral fat accumulates in cortisol-excess and accounts for increased cardiovascular risk. In this study, we investigate whether the LDDST offers additional infor...

Context: HIF-1α is frequently upregulated in many tumour types and has been shown to be critical for radio- and chemosensitivity in pre-clinical studies. However the regulation and function of HIF-1α is unknown in thyroid carcinomas.Objectives: Here, we evaluated basal expression and regulation of HIF-1α and target genes in primary thyroid carcinomas and in thyroid cancer cell lines (NPA, FTC-133, ARO).Design and out...

Background: Size at birth has been shown to have important consequences on later health, including the development of the metabolic syndrome. Tissue sensitivity to cortisol is regulated, in part, by the GCR and alterations in GCR expression have been observed in obesity and type 2 diabetes.Objectives: To examine whether birth weight influences the expression of GCR mRNA in skeletal muscle (SM) at days 7 and 14 of postnatal life.Met...

Familial Juvenile Hyperuricaemic Nephropathy (FJHN) is an autosomal dominant disorder that is associated with gout and progressive renal failure. FJHN in 43 families has been reported to be caused by mutations in the UMOD gene, which encodes Uromodulin, also known as the Tamm-Horsfall Glycoprotein, and two families have been reported to have mutations in the transcription factor Hepatocyte Nuclear Factor 1β (HNF-1β), mutations of which usually cause maturity-o...

BackgroundOne in 80 pregnancies is ectopic. Chlamydia trachomatis infection is the major risk factor for ectopic pregnancy yet knowledge of the pathogenic events that lead from Chlamydial infection to ectopic pregnancy is unclear. Furthermore, a blood test that can reliably differentiate an ectopic from an intra-uterine pregnancy is not available. The innate immune system is likely to offer protection against Chlamydia and the natural anti-...

T3-receptor alpha (TRa) is the predominant TR isoform in bone. To investigate its function, we analysed mice harbouring a dominant negative R384C mutation in TRa1 (TRa1m/+). The homozygous TRa1m/m mutation is lethal whereas heterozygotes are euthyroid displaying only transient postnatal hypothyroidism. Critically, dominant negative activity of the mutation is overcome by a 10-fold increase in T3, which is achieved by crossing TRa1m/+ mutants wi...

In developmental studies of mice lacking T3-receptor alpha (TRa0/0) and beta (TRb−/−) we demonstrated delayed endochondral ossification, reduced mineralisation and short stature in TRa0/0 mice, despite euthyroidism. In contrast, TRb−/− mice, which display thyroid hormone resistance with elevated T4 and T3 levels, have advanced ossification, increased mineralisation and accelerated growth. T3-target gene studie...