Leptin has been shown to modulate deiodinase type 1 (D1) and type 2 (D2) enzymes responsible for thyroxine (T4) to triiodothyronine (T3) conversion. Previously, it was demonstrated that a single injection of leptin in euthyroid fed rats rapidly increased liver, pituitary, and thyroid D1 activity, and simultaneously decreased brown adipose tissue (BAT) and hypothalamic D2 activity. We have now e...

Changes in enzymatic and structural properties of ventricular myosin in thyrotoxic rabbit hearts have been investigated extensively. However, there is little information regarding the effect of thyroid hormone on the atrial myosin. In this study, we have compared enzymatic and structural changes of ventricular and atrial myosin from euthyroid, hypothyroid, and hyperthyroid rabbits. In euthyroid...

1. Renal responses to changes in renal perfusion pressure were studied in anaesthetized hyperthyroid (thyroxine, 300 pg day' kg') and hypothyroid (methimazole, 0.03% via drinking water) rats to determine whether an abnormality in the pressurediuresisnatriuresis phenomenon is involved in the resetting of kidney function in these disorders. 2. There were no significant differences between control...

The kinetics of type III iodothyronine deiodinase (5-D) in rat placenta and brain and the role of phospholipids in enzyme activity were determined. Pregnant Sprague-Dawley rats were given either vehicle (control group) or T4 (15 jug/100 g bw/day; hyperthyroid group) from the 14th to the 21st day of gestation. Mitochondrial-microsomal fractions of the placenta and brain were used as the source o...

To evaluate the relationship between circulating adiponectin and insulin sensitivity in patients with hyperthyroid Graves' disease, we studied 19 adult patients with this disease and 19 age- and sex-matched euthyroid controls. All hyperthyroid patients were treated with antithyroid drugs and were re-evaluated after thyroid function normalized. Before antithyroid treatment, the adiponectin plasm...

We aimed in this study to determine the changes due to hyperthyroidism or hypothyroidism in serum ferritin, iron, transferrin, vitamin Bn and erythrocytic parameters and to investigate the interrelationships between these parameters .Serum ferritin, iron, total iron-binding capacity (transferrin), vitamin B12, total andfree trüodothyronine (TT3 and FT3) , total andfree thyroxine (TT4 and FT4), ...

Abnormalities of carbohydrate metabolism in hyperthyroid patients have been long noted. Elevated proinsulin level is considered as an early marker of B-cell impairment. Proinsulin levels in hyperthyroid patients decreased after antithyroid drug therapy. However, proinsulin in hypothyroid patients was only rarely reported, and the difference was only demonstrated after glucose stimulation-there ...

Single ventricular myocytes were isolated by collagenase digestion from the hearts of 6-8-month-old male Wistar rats in either the control (euthyroid) state or after 7 days of daily injection of 0.64 mg/kg thyroxine (hyperthyroid). Myocytes were field-stimulated from slack length, and contraction was measured with an inverted microscope-photodiode array-computer apparatus. The effect of pacing ...

Radioiodine therapy is commonly used in hyperthyroid cats and has a high success rate, ranging from 85-95%. As in humans, thyroid volume has been reported to influence radioiodine therapy outcome in hyperthyroid cats. The purpose of this study was to relate total thyroid volume, calculated by a newly constructed formula for feline patients (0.438 × length × width²), to the outcome of radioiodin...

By experiments on cells (neurons, hepatocytes, and fibroblasts) that are targets for thyroid hormones and a randomized clinical trial on iatrogenic hyperthyroidism, we validated the concept that L-carnitine is a peripheral antagonist of thyroid hormone action. In particular, L-carnitine inhibits both triiodothyronine (T3) and thyroxine (T4) entry into the cell nuclei. This is relevant because t...