We have investigated the effects of thyroidectomy, hypophysectomy and 3,3',5-tri-iodothyronine replacement on protein synthesis and degradation in skeletal muscle in vivo. Thyroidectomy resulted in a decrease in the rate of protein synthesis as a result of a loss of RNA. However, RNA activity, the rate of protein synthesis per unit of RNA, was not decreased. This was the case in both young grow...

By using a highly specific radioimmunoassay the formation of tri-iodothyronine by the deiodination of thyroxine was studied in rat liver homogenate. Several observations suggest that the reaction observed is enzymic in nature. Pre-heating the homogenate for 30 min at 56 degrees C completely abolished conversion of thyroxine into tri-iodothyronine; the component of rat liver homogenate responsib...

Brown adipose tissue iodothyronine 5'-deiodinase activity is significantly lower in 17-day pregnant rats compared with virgin controls and remains low during late pregnancy and lactation. It fully recovers with abrupt weaning, but only partially with spontaneous weaning. Even though this profile of changes is remarkably in step with the known pattern of modifications in brown fat thermogenesis ...

Accumulating evidence suggests that genes of the hypothalamic-pituitary-thyroid pathway influence susceptibility to hypertension. Type 2 iodothyronine deiodinase is responsible for the conversion of thyroxine to tri-iodothyronine for use in peripheral tissues. The present study evaluated whether a type 2 iodothyronine deiodinase nonsynonymous polymorphism, threonine 92 to alanine (Thr92Ala), is...

1. Normal and thyroidectomized rats were treated with near-physiological doses of tri-iodothyronine. Liver mitochondria were isolated and incubated with radioactive amino acids. In normal rats tri-iodothyronine caused only a slight stimulation of incorporation into mitochondrial protein, but in thyroidectomized animals the incorporation was doubled. 2. There was a lag period of about 36 hr. aft...

1. In order to investigate the molecular mechanisms determining the hypertrophic response of the ventricular myocardium to thyroid hormone administration, changes in left and right ventricular expression of the c-myc, c-fos and H-ras proto-oncogenes in response to treatment with 3,3',5-tri-iodothyronine were defined. 2. Adult female Wistar rats were treated with daily subcutaneous injections of...

To evaluate the concentrations of serum lipids and lipoproteins and their correlations together and withthyroid hormones in gray necked ostrich (Struthio camelus), the serum levels of cholesterol, triglyceride,total lipids, very low density lipoproteins (VLDL-cholesterol), low density lipoproteins (LDL-cholesterol)and high density lipoproteins (HDL-cholesterol) and their correlations with tri-i...

Present knowledge of the metabolism of the thyroid hormones in the kidney is confined mainly to information obtained from experiments with 231I-labelled thyroxine and tri-iodothyronine. Gross & Leblond (1951 a) found that after the administration of ['31I]thyroxine to rats or mice, the kidney concentrated radioactivity from the blood. Subsequent chromatographic analysis of butanol extracts of k...

1. Binding of l-tri-[(125)I]iodothyronine to the cytosol fraction of normal human female breast adipose tissue was investigated by the charcoal adsorption method. Equilibrium of binding was reached after 120s at 25 degrees C. 2. The l-tri-[(125)I]iodothyronine-binding component is a protein; this was confirmed by experiments in which binding was totally lost after heating the cytosol fraction f...