Searchable abstracts of presentations at key conferences in endocrinology

ea0015oc36 | Thyroid | SFEBES2008

Increased skeletal mineralisation in mice lacking type 2 iodothyronine deiodinase

Bassett JH Duncan , Boyde Alan , Howell Peter GT , Galliford Thomas M , Archanco Marta , St Germain Donald L , Galton Valerie A , Williams Graham R

The prohormone T4 represents the majority of circulating thyroid hormones, whereas 80% of the active hormone T3 is derived from T4 by the actions of the type 1 and type 2 deiodinase enzymes (D1 and D2). Local generation of T3 by D2 regulates ligand supply to the nuclear T3-receptor in pituitary, brown adipose tissue and brain, and this enzyme is also expressed in bone. Hypothyroidism in children causes delayed bone age and growth retardation, whereas thyrotoxicosis in adults c...

ea0015oc40 | Thyroid | SFEBES2008

Direct actions of T3 in proliferating chondrocytes regulate endochondral ossification and linear growth

Bernstein Nicholas D , Swinhoe Rowan , Kester Monique HA , Archanco Marta , Lu Yan , O'Shea Patrick J , Visser Theo J , Bassett JH Duncan , Williams Graham R

Hypothyroidism causes delayed ossification and growth retardation. T3 stimulates hypertrophic chondrocyte differentiation whereas unliganded T3 receptors (TRs) repress gene expression and maintain cell proliferation in the absence of hormone. During development the type 3 deiodinase enzyme (D3) inactivates thyroid hormones and prevents T3-access to the fetus. At birth diminishing D3 activity and increasing T3 availability triggers the onset of cell differentiation and correlat...