Neonatal changes in plasma total and free iodothyronine levels were monitored in 18 Limousin X Romanov suckling lambs (experiment 1) and 24 Limousin X Romanov animals bottle-fed in standardized conditions (experiment 2). In the two experiments, plasma free T3 levels were closely related to total T3 levels, whereas some differences could be observed between total and free plasma T4 levels. The n...

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...

Thyroid hormones play a critical role in the growth of many organs, especially the brain. Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) interact with the thyroid pathway and may disturb neurodevelopment. This prospective study was designed to examine associations between maternal blood PBDEs and PCBs in early pregnancy and levels of thyroid hormones in maternal and...

We compared the uptake, metabolism, and biological effects of tetraiodothyroacetic acid (Tetrac) and rT3 in anterior pituitary cells with those of T4 and T3. Cells were isolated from adult male Wistar rats and cultured for 3 days in medium with 10% fetal calf serum. Uptake was measured at 37 C in medium with 0.1% BSA for [125I]Tetrac (200,000 cpm; 240 pM) and [125I]T4 (100,000 cpm; 175 pM) or w...

Concannon, Patrick W., V. Daniel Castracane, Richard E. Rawson, and Bud C. Tennant. Circannual changes in free thyroxine, prolactin, testes, and relative food intake in woodchucks, Marmota monax. Am. J. Physiol. 277 (Regulatory Integrative Comp. Physiol. 46): R1401–R1409, 1999.— Woodchucks (n 5 12–14/group) with circannual cycles entrained to northern versus southern hemisphere photoperiods wer...

Serum free thyroxine (FT4), total T4 (T4) and total T3 (T3) were determined by radioimmunoassay in 1,114 adults during a periodic health evaluation to detect unsuspected thyroid dysfunction. As a result, 3 patients with hyperthyroidism, 4 with hypothyroidism, 3 taking thyroid medication, 4 with chronic thyroiditis, 1 with simple goiter and 3 women under estrogen administration were found. Free ...

Three women are described from a study of patients with postpartum thyroiditis whose sera gave spuriously increased concentrations of free thyroid hormone because of antibody binding of radiolabeled thyroxin (T4) and triiodothyronine (T3) analogs. All of the women showed increased serum concentrations of thyroid autoantibodies. The antibody binding of radiolabeled analogs and its effect on free...

KTBPA, 2.3 X 108; and KTBG, 1.7 X 1010. t Deceased 26 January 1968. Received for publication 12 November 1968 and in revised form 7 February 1968. INTRODUCTION The existence of L-thyroxine (T4)-binding prealbumin (TBPA) as a normal constituent of human serum has been satisfactorily demonstrated both by a variety of electrophoretic techniques and by its isolation from human serum (1-3). Neverthe...

Various experiments have indicated the presence in whole human serum of three major thyroxine (T4)-binding 1 proteins: T4-binding globulin (TBG), T4-binding prealbumin (TBPA), and albumin (1, 2). It is well established that, in vitro, TBG and TBPA are the major T4-binding proteins, whereas albumin is a relatively weak secondary carrier (3-5). These proteins interact with the hormone in a revers...