OBJECTIVE The levels of uncoupling protein 2 (UCP2) mRNA and determinants of respiration (ATP synthesis, proton leak and non-mitochondrial respiration) were evaluated in Kupffer cells isolated from the livers of normal euthyroid, acute hyperthyroid and chronic hyperthyroid rats. METHODS After liver perfusion, Kupffer cells were purified by density-gradient centrifugation followed by counterfl...

We sought to examine the breathing pattern, inspiratory drive and chemosensitivity of hyperthyroid patients and to explore the interactions between their thyroid hormones, basal metabolism and chemosensitivity. We studied 15 hyperthyroid patients and 15 sex- and age-matched controls. Thyroid hormone levels, arterial blood gas tensions, lung volumes, diffusing capacity for CO, maximal respirator...

BACKGROUND Atrial fibrillation (AF) is the most common cardiac complication of hyperthyroidism. The influence of the time of cardioversion on hyperthyroidism-induced AF remains unclear. The aim of this study was to compare short-term outcomes of early electrical cardioversion for AF in hyperthyroid and euthyroid patients. METHODS AND RESULTS Sixty-seven subjects with persistent AF (duration, ...

BACKGROUND Hyperthyroidism and chronic kidney disease (CKD) are common in elderly cats. Consequently, both diseases often occur concurrently. Furthermore, renal function is affected by thyroid status. Because changes in renal perfusion play an important role in functional renal changes in hyperthyroid cats, investigation of renal perfusion may provide novel insights. OBJECTIVES To evaluate re...

OBJECTIVE The mechanisms of dyspnea and exercise intolerance have not been fully elucidated. We aimed to investigate the clearance rate of technetium-99m diethyltriaminepentaaceticacid (Tc-99m DTPA) from lungs in hyperthyroid patients without clinical evidence of lung disease and to explore the interactions between their Tc-99m DTPA radioaerosol lung scintigraphy, spirometric measurements, and ...

The development of spontaneous hyperthyroidism following primary hypothyroidism is an unusual occurrence. We report two cases of confirmed primary hypothyroidism who subsequently became hyperthyroid. Thyroid stimulating antibodies were present in the sera of both patients during the hyperthyroid state. The significance of this sequence of events is discussed and a possible explanation proposed.

The effects of short-term hyperthyroidism in vivo on the status of the components of the fat-cell hormone-sensitive adenylate cyclase were investigated. The number of beta-adrenergic receptors was elevated by about 25% in membranes of fat-cells isolated from hyperthyroid rats as compared with euthyroid rats, but their affinity for radioligand was unchanged. Membranes of hyperthyroid-rat fat-cel...

OBJECTIVES This study was conducted to investigate the effects of thyroid hormone on the electrophysiological characteristics of pulmonary vein (PV) cardiomyocytes. BACKGROUND Hyperthyroidism is an important etiology of paroxysmal atrial fibrillation (AF). Pulmonary veins are known to initiate paroxysmal AF. METHODS The action potential and ionic currents were investigated in single rabbit ...

Phosphorylation of sarcoplasmic reticulum (SR) Ca2+-cycling proteins by a membrane-associated Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) is a well-documented physiological mechanism for regulation of transmembrane Ca2+ fluxes and the cardiomyocyte contraction-relaxation cycle. The present study investigated the effects of L-thyroxine-induced hyperthyroidism on protein expressio...

Background—Hyperthyroidism increases heart rate, contractility, cardiac output, and metabolic rate. It is also accompanied by alterations in the regulation of cardiac substrate use. Specifically, hyperthyroidism increases the ex vivo activity of pyruvate dehydrogenase kinase, thereby inhibiting glucose oxidation via pyruvate dehydrogenase. Cardiac hypertrophy is another effect of hyperthyroidis...