A cell-free system derived from uninfected Escherichia coli previously was shown to synthesize beta-glucosyl transferase in response to T4 DNA. This same in vitro system, when incubated at slightly higher magnesium concentrations, also synthesized enzymatically active lysozyme. The lysozyme activity that appeared was judged to be T4-specific since antibodies prepared against authentic T4-lysozy...

We have recently shown that it is not possible to restore euthyroidism completely in all tissues of thyroidectomized rats infused with T4 alone. The present study was undertaken to determine whether this is achieved when T3 is added to the continuous sc infusion of T4. Thyroidectomized rats were infused with placebo or T4 (0.80 and 0.90 microgram/100 g BW.day), alone or in combination with T3 (...

Polybrominated diphenyl ethers (PBDEs) have been shown to disrupt thyroid hormone (TH) functions on experimental animals, and one of the proposed disruption mechanisms is the competitive binding of PBDE metabolites to TH transport proteins. In this report, a nonradioactive, site-specific fluorescein-thyroxine (F-T4) conjugate was designed and synthesized as a fluorescence probe to study the bin...

Context l-Thyroxine (l-T4) therapy of central hypothyroidism (CH) is guided by measurements of serum free thyroxine (FT4), which should be above the midnormal range value (MNRV). In some countries, novel formulations of oral l-T4 (liquid or softgel) are available further to the classic tablets. The intestinal absorption of either novel formulation is greater than tablets in patients with primar...

Rainbow trout possess ultraviolet-sensitive (UVS) cones in their retina that degenerate naturally during development. This phenomenon can be induced with exogenous thyroxine [T4, a thyroid hormone (TH)] treatment. However, the previous T4 exposure experiments employed static water immersion; a method that could introduce confounding stress effects on the fish. Because of this, it was uncertain ...

The active site sequence of T4 thioredoxin, Cys-Val-Tyr-Cys, has been modified in two positions to Cys-Gly-Pro-Cys to mimic that of Escherichia coli thioredoxin. The two point mutants Cys-Gly-Tyr-Cys and Cys-Val-Pro-Cys have also been constructed. The mutant proteins have similar reaction rates with T4 ribonucleotide reductase as has the wild-type T4 thioredoxin. Mutant T4 thioredoxins with Pro...

Thyroid gland explant cultures from prometamorphic Xenopus laevis tadpoles were evaluated for their utility in assessing chemicals for thyroid hormone (TH) synthesis disruption. The response of cultured thyroid glands to bovine thyroid stimulating hormone (bTSH) and the TH synthesis inhibitors methimazole, 6-propylthiouracil, and perchlorate was determined. Thyroid glands continuously exposed f...

OBJECTIVE To evaluate the results of T4, TSH analysis and pattern of presentation in babies born at our hospital. METHOD We retrospectively reviewed the data collected from T4, TSH screening on all babies delivered at our Hospital, where the blood was drawn within the first 4 days of life. Period under evaluation was from October 1995 to October 1998. Shifa Reference values were used. RESUL...