It is a fact of great interest that when 131I-thyroxine and 131I-triiodothyronine are exogenously given, they are highly concentrated in the anterior hypothalamus, median eminence, and hypophysis. Schittenhelm and Eisler (1932) already found that the intravenous injection of 1.0mg/kg of thyroxine (T4) into dogs, cats and rabbits elevated iodine concentration in the tuber cinereum 10times. Since...

Thyroid hormone is one of the critical hormones in mammals and plays an indispensable role in development as well as in lipid and carbohydrate metabolism and energy generation. The thyroid gland secretes mainly L-thyroxine (T4) into the circulation where it is converted to 3,5,3′-triiodothyronine (T3) in liver and kidney. Most of the serum T3 is derived from this conversion, which is catalyzed ...

Concentrations of free thyroxin (T4) and free triiodothyronine (T3) were measured in sera from pregnant women, in subjects with congenitally increased or decreased thyroxin-binding globulin (TBG), and in euthyroid controls. Measured free hormone concentrations were compared with calculated values for free hormone derived from concentrations of total T4, total T3, and binding proteins. Measured ...

The interest in the relationship between thyroid dysfunction and obesity is on the increase. This study compares the triiodothyronine-to-thyroxine (T3/T4) ratio in obese and lean children and adolescents, and correlates thyroid hormones with body mass index (BMI) in obese Nigerian children. It is a retrospective study of records of 76 obese children and adolescents with a BMI of 31.7 ± 0.1 kg/m...

The uptake of [125I]T4 was investigated in cultured anterior pituitary cells isolated from adult fed Wistar rats and cultured for 3 days in medium containing 10% fetal calf serum. Experiments were performed with [125I]T4 (10(5) to 2 x 10(6) cpm; 0.35-7 nM) in medium containing 0.5% or 0.1% BSA. The uptake of [125I]T4 increased with time and showed equilibrium after around 1 h of incubation. The...

BACKGROUND Left ventricular (LV) diastolic function has received much attention recently. However, few studies have evaluated LV diastolic function in the perioperative period. The aim of this study was to elucidate perioperative changes in diastolic function using tissue Doppler imaging (TDI) in patients undergoing repair of an infrarenal abdominal aortic aneurysm (AAA). METHODS Eight patien...

A study was carried out on 57 patients with chronic renal failure in a hospital in Kerman city, Islamic Republic of Iran. Blood samples were taken before and after haemodialysis to measure blood urea nitrogen and serum creatinine, triiodothyronine (T3) and thyroxine (T4) levels. Findings revealed that before dialysis T4 in 11 cases and T3 in 29 cases were lower than the normal range, but after ...

We evaluated the effects of temperature and humidity on thyroid hormones (T4, T3) and thyrotropin (TSH) measured in blood spots dried on filter paper. RIAs for T4 and T3 blood spots were optimized to measure these analytes over the neonatal and euthyroid adult reference intervals. Sensitivities of the T3 and T4 assays were 0.5 and 10 nmol/L, respectively. A blood-spot immunoradiometric assay fo...

Thyroid hormones (THs) are essential for fetal and post-natal nervous system development and also play an important role in the maintenance of adult brain function. Of the two major THs, T4 (3,5,3',5'-tetraiodo-l-thyronine) is classically viewed as an pro-hormone that must be converted to T3 (3,5,3'-tri-iodo-l-thyronine) via tissue-level deiodinases for biological activity. THs primarily mediat...