1Department of Chemistry, Rutgers University, Camden, NJ, USA; Center for Computational and Integrative Biology, Rutgers University, Camden, NJ, USA 2Johns Hopkins Bloomberg School of Public Health, Center for Alternatives to Animal Testing (CAAT), Baltimore, MD, USA 3National Toxicology Program Interagency Center for the Evaluation of Alternative Toxicological Methods, National Institute of En...

We have identified an individual whose thyroxine (T4) concentration was undetectable with Abbott's fluorescence polarization immunoassay (FPIA) but within the reference range by radioimmunoassay or EMIT (Syva). The patient's thyrotropin, triiodothyronine, and T-uptake values were within the normal range. The T4 concentration measured by FPIA increased to normal when the immunoglobulin fraction ...

To investigate the role of thyroxine-binding globulin (TBG) and albumin in the availability of thyroid hormones to peripheral tissues, comprehensive kinetic studies of thyroxine (T4) and triiodothyronine (T3) were carried out in eight subjects with familial dysalbuminemic hyperthyroxinemia (FDH), in four subjects with inherited TBG excess, and in 15 normals. In high-TBG subjects, the reduction ...

Some equilibrium dialysis determinations of free thyroxine (T4) vary directly with thyroxine-binding globulin (TBG) concentration. This apparent TBG dependence has been limited to methods involving radiolabeled T4 added to the dialysis system (tracer dialysis). In this study we compared tracer dialysis with direct dialysis for determining free T4 and obtained the following results (mean +/- SD)...

We have studied whether, or not, tissue-specific regulatory mechanisms provide normal 3,5,3'-triiodothyronine (T3) concentrations simultaneously in all tissues of a hypothyroid animal receiving thyroxine (T4), an assumption implicit in the replacement therapy of hypothyroid patients with T4 alone. Thyroidectomized rats were infused with placebo or 1 of 10 T4 doses (0.2-8.0 micrograms per 100 gr...

To determine the effect of ethanol on peripheral metabolism of T4, deiodinative clearance of T4 and serum concentration of T4, T3 and rT3 were measured in rats isotopically equilibrated with T4. Ethanol 8 g/Kg weight/day was given for 3 days to fasted rats and the results were compared with those normally fed or totally fasted animals. In fasted rats, deiodinative clearance of T4 and serum T4 a...

The electrochemical response of thyroxine (T4) at a carbon paste electrode (CPE) in the presence of cetyltrimethylammonium bromide (CTAB) was investigated. It gave a well-defined oxidation peak at 0.80 V and a sensitive reduction peak at 0.40 V. Compared with the indiscernible signal in the absence of CTAB, the reduction current of T4 at CPE was greatly enhanced in the presence of CTAB, due to ...

background: levothyroxine is commonly used in the treatment of patients with hypothyroidism. levothyroxine is often administered in the morning, on an empty stomach, to increase its absorption. however, many patients have trouble for taking levothyroxine in the morning. the aim of this study was to evaluate the effect of changing administration time of levothyroxine from before breakfast to bef...

Thyroxine(T4)-binding to serum proteins in primates; catarrhini, prosimiae, and platyrrhini were studied by polyacrylamide gel electrophoresis T4 binding analysis. From the electrophoretic analysis, it was shown that thyroxine-binding proteins similar to human thyroxine-binding globulin (TBG) and thyroxine-binding prealbumin (TBPA) were present in catarrhini and prosimiae species, but not in pl...