Thyroid hormones enhance aerobic metabolism favoring oxidative stress which may lead to covalent damage of various molecules including DNA. Previous investigations revealed that thyroid hormones induce DNA damage on human lymphocytes and sperm in the in vitro Comet assay. However, cytogenetic evaluation of genotoxic effects of thyroxine gave equivocal results: increase of sister chromatid excha...

The possibility has been examined that thyroxine may be degraded by an intermediate free radical in the oxidation of linoleate catalyzed by lipoxidase. Such a reaction has been observed and the lipid radical with which thyroxine reacts is suggested to be enzyme attached RO; proposed by Tappel (in W. 0. LUIVDBERG (Editor), A&oxidation and antioxidants, Vol. I, Interscience Publishers, New York, ...

Triiodothyronine and thyroxine induce a 3-fold increase in the rate of growth of GH(1) cells in culture. To study further the action of these hormones, we examined the binding of [(125)I]triiodothyronine and purified [(125)I]thyroxine to cellular fractions after incubation with intact cells in serum-free medium. High-affinity, low-capacity binding sites for the hormones were demonstrated in nuc...

Free radicals are all known to damage cell components. The present study was designed to evaluate the free radical generation in the testis and liver and also to determine the testicular and hepatic antioxidant enzyme activities with and without catechin administration in thyroxine induced male Sprague-Dawley rats. The experimental animals were divided into four groups, six on each division. L-...

A method is described for assessing thyroid status by estimating plasma thyroxine and dialysable thyroxine and multiplying these two to give a dialysable thyroxine index. Certain difficulties which sometimes invalidate other thyroid function tests are avoided. The techniques are relatively simple and clear differentiation between thyroid states can usually be made.

Craniosynostosis (CS) is the premature fusion of cranial sutures during embryonic development, and this results in intracranial pressure skull deformities. Thyrotoxicosis, specifically maternal hyperthyroidism, has been linked to development CS. Our lab currently validating an avian model thyroxine-induced CS study mechanism involved thyroxine-enhanced ossification. We hypothesized that thyroxi...

The efficacy of iodide and thyroxine in ameliorating the several deficiencies occasioned by thyroidectomy in male and female rats was compared in order to obtain indirect evidence for extrathyroidal thyroxine formation. More direct refutation of the opposing concept that iodide simulates the action of thyroxine was also sought in experiments with propylthiouracil (PTU) and tribromothyronine. In...

Published data on 4-week-long administration of exogenous thyroxine in broiler breeder hens to decline the cold-induced ascites in their progeny suggest that the long-term maternal hyperthyroidism would affect egg quality characteristics traits in Cobb 500 broiler breeder hens. Seventy 47-w-old broiler breeder Cobb 500 hens (5 replicates and 7 hens each) were assigned in separate cages and allo...