Endocrine Abstracts

Recent controversial studies in mice imply that TSH inhibits bone remodelling, suggesting TSH-deficiency rather than thyroid hormone excess causes bone loss in thyrotoxicosis. Measurement of the TRH-stimulated rise in TSH following three days administration of graded doses of T3 is the gold-standard for determining resistance to thyroid hormone (RTH). During this test, T3 excess coupled with suppressed TSH should induce high bone turnover, whilst administration of TRH causes a...

Increased hypothalamic–pituitary–thyroid (HPT) axis activity results in high bone turnover. T3 stimulates osteoblast and osteoclast activities, whereas TSH is proposed to inhibit bone turnover directly. Resolving the relative importance of T3 and TSH is complicated by their physiological inverse relationship. We studied 10 controls and 4 patients with resistance to thyroid hormone (RTH), in which mutation of thyroid hormone receptor beta (THR...

Lithium increases retention of Iodine-131 in the thyroid gland and inhibits thyroid hormone release following radioactive iodine (RAI) administration. However, outcomes of studies of the effects of lithium on the efficacy of RAI are conflicting. The aim of this study was to assess whether adjuvant lithium increases the efficacy of RAI treatment in hyperthyroidism. A retrospective cohort study was performed of 204 hyperthyroid patients (163 Graves’ disease, 26 toxic multin...

Background: Thyroid disease is associated with BMI with hyperthyroidism causing weight loss and hypothyroidism leading to weight gain. However, the relation of body weight distribution to thyroid function in euthyroid individuals is unclear. This study assessed body composition in euthyroid women.Methods: Euthyroid women (n=1072) from the Osteoporosis and Ultrasound Study (OPUS), a population based cohort study recruited participants from 5 Europe...

OPUS is a population-based prospective cohort study of post-menopausal women from five European cities. We investigated whether TSH, fT4 and fT3 are associated with fracture risk, bone mineral density (BMD) at hip and spine, bone formation (osteocalcin, procollagen type 1 N-terminal propeptide), bone resorption (N- and C-telopeptides of type 1 collagen, NTX, CTX), pulse rate, grip strength and balance. Vertebral fractures were determined at baseline and 6 years follow-up. Usin...

(This poster is based on OC33)...

T3-action is regulated by three iodothyronine deiodinases, which contain selenium in the active site. It is proposed that Se availability regulates thyroid function. OPUS is a European population-based prospective cohort study of post-menopausal women in which we showed thyroid function within the upper normal range is associated with reduced bone mineral density (BMD) and increased non-vertebral fracture risk. Using strict exclusion criteria we defined reference ranges for th...

Hypothyroidism and thyrotoxicosis have detrimental effects on skeletal development and adult bone strength. These effects result from thyroid hormone actions in bone, although a direct role for TSH in osteoblasts and osteoclasts was postulated following analysis of TSH receptor (TSHR) null mice. This hypothesis remains controversial as other studies failed to demonstrate osteoblast or osteoclast responses to TSH in vitro. Thyrostimulin is a heterodimeric glycoprotein ho...