BACKGROUND Data suggest symptoms of hypothyroidism persist in 5-10% of levothyroxine (L-T4)-treated hypothyroid patients with normal serum thyrotrophin (TSH). The use of L-T4 + liothyronine (L-T3) combination therapy in such patients is controversial. The ETA nominated a task force to review the topic and formulate guidelines in this area. METHODS Task force members developed a list of releva...

Broiler chickens were reared in batteries and fed diets designed to determine the effects of either ascorbic acid, aspirin (acetylsalicylic acid), lysine, or thiouracil on thyroid weight and serum thyroid hormone concentrations. Thyroxine (T4) and 3,5,5'-triiodothyronine (T3) concentrations in serum were determined by radioimmunoassay. Neither ascorbic acid nor lysine affected T3 or T4 concentr...

BACKGROUND Little is known about changes in thyroid function in obese children. An influence of leptin on thyroid hormone synthesis has been proposed. AIMS To examine thyroid function and leptin concentrations in obese children. METHODS Triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH), and leptin were measured in 118 obese children (aged 4.5-16 years); thyroid functi...

Although the normal thyroid gland secretes both levothyroxine (L-T4) and levotriiodothyronine (L-T3), normalization of serum TSH with L-T4-replacement therapy alone in hypothyroidism is generally believed to result in a normal serum L-T3 and to reflect a euthyroid state. However several recent studies suggest that this may not be the case. Accordingly, the relationship between serum free L-T4 a...

One hundred and forty seven clinically proven hyperthyroid subjects were studied using radioimmunoassay techniques for the estimation of serum thyroid hormones and pituitaryTSH concentrations. In females toxic goitre was more frequently seen in the age group 21 to 30 years and in males 31 to 40 years. The mean levels for serum T4, T3, FT4 and FT1 were significantly elevated while the mean level...

Studies of the possibility that thyroxine (T4) is converted to 3.5,3'-triiodo-L-thyronine (T3) in the extrathyroidal tissues in man have been conducted in 13 patients, all but two of whom were athyreotic or hypothyroid, and all of whom were receiving at least physiological replacement doses of synthetic sodium-L-thyroxine.T3 was found in the sera of all patients, in concentrations ranging betwe...

Intrauterine growth restriction (IUGR) is associated with accelerated growth and increased adiposity in early life due to unknown mechanisms, which could include increased thyroid hormone (TH) action. We hypothesized that placental restriction (PR) of fetal growth would increase circulating TH concentrations and alter their response to fasting, and that these would relate to growth and body com...