In a seemingly wasteful fashion, the thyroid gland focuses its effort into secreting an inactive version of thyroid hormone T4. In fact, a hormone, from the Greek word for impulse, is a biologically active molecule, so in the case of thyroid hormone, the actual active hormone is that of the triply iodinated derivative, T3. To successfully produce T3, the human thyroid processes about 1000 nmol ...

The degree to which thyroid functions are affected by non-thyroid illness and an assessment of its correlation with mortality was evaluated. Thirty infants (20 M, 10 F) with a mean age of 433 +/- 3.28 months (+/- 1 SD), with severe acute systemic illness and 30 healthy controls, age and sex matched, were studied for total serum T3, T4 and TSH levels at admission and recovery or before death. Se...

A stimulatory effect on bone marrow cellularity was observed in normal and nephrectomized rats continuously infused with T3 and T4. Results of bone marrow studies are expressed in absolute numbers of total nucleated erythroid cells per milligram of femoral marrow at the beginning and after 8 hr of continuous intravenous infusions. Administration of T3 and T4 to nephrectomized rats produced a ma...

Recent studies indicate that co-planar 3,3',4,4',5-pentachlorobiphenyl (PCB) congeners or their metabolites may disrupt thyroid function in fishes. Although co-planar PCB have been detected at microgram per kilogram levels in fish from contaminated areas, few studies have examined mechanisms whereby, co-planar PCBs may alter thyroid function in fish. We treated immature lake trout by intraperit...

the main goal of this study was to evaluate the possible effect of whole-body magnetic field(mf) exposure on the variations of corticosterone, free-t3, free-t4 and malonyl dialdehyde inplasma in 48 adult white new zealand male rabbits. animals were divided into six groups namely,c1 (normal diet, not exposed), c2 (normal diet, sham exposed), t1 (normal diet, exposed toelectromagnetic field), c3 ...

Because little has been published on early effects of treatment with amiodarone on thyroid function, we studied serum total and free thyroid hormone, reverse T3, and TSH levels in patients with cardiac arrhythmias during the first 10 days of treatment with a loading dose of amiodarone by iv infusion. Twenty-four patients were enrolled in the study. A standardized loading regimen for the i.v. in...

Studies were performed to elucidate the nature of the pathway of hepatic thyroxine (T4) metabolism that is activated by inhibitors of liver catalase. For this purpose, the metabolism of T4 in homogenates of rat liver was monitored with T4 labeled with 125I either at the 5'-position of the outer-ring (125I-beta-T4) or uniformly in both the outer and inner rings (125I-U-T4). In homogenates incuba...