OBJECTIVE Pubertal gynaecomastia is a frequent phenomenon occurring in 20-40% of otherwise healthy adolescent boys. Little is known about the aetiology of pubertal gynaecomastia. Markedly elevated thyroid hormone levels in adults with hyperthyroidism are associated with gynaecomastia. DESIGN A cross-sectional examination of 444 healthy boys with and without pubertal gynaecomastia. METHODS W...

An experiment on Lohmann male broilers was conducted to evaluate the effect of different energy and protein levels on broiler performance and plasma concentrations of growth hormone (GH), thyroxine (T4), and triiodothyronine (T3). 600 day-old broilers were fed on either 2800(low-energy) or 3200(high-energy) Kcal ME/Kg diets with different protein levels during three periods of starter, grower a...

Synthesis of thyroid hormones, thyroxine (T4) and tri-iodothyronine (T3), in the human fetus starts from 17 to 19th weeks of gestation. Despite the majority of normal pregnant women reaching adequate levels of circulating thyroid hormones, in some cases, women with normal pregnancies have low level of free T4 during first trimester of pregnancy, suggesting that T4 action may be compromised in t...

The Thyroid Status was studied by estimating the total serum levels of T3 and T4 by radioimmunoassay (RIA) and TSH by radioimmunometric Assay (IRMA) from 635 school children (8-20 years; male 129, female 506) of the Dibrugarh district: a chronic endemic goitrous region of India. The results were compared with the control group of 147 (male 48, female 99) of healthy medical students of the same ...

The effects of open heart surgery on various parameters of thyroid-pituitary function were studied in 11 patients. The pattern of hormonal changes was variable. T4 concentration increased during anaesthesia and bypass, following which it returned to normal once haemodynamic stability had been regained. The pattern of change in T3 concentration did not follow consistently that of T4 and the prop...

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...