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Your search keyword '"Malliopoulou, V. A."' showing total 4 results
Start Over Author "Malliopoulou, V. A." Topic thyroxine
4 results on '"Malliopoulou, V. A."'

1. Long-term thyroxine administration increases heat stress protein-70 mRNA expression and attenuates p38 MAP kinase activity in response to ischaemia.

Author

Pantos CI, Malliopoulou VA, Mourouzis IS, Karamanoli EP, Tzeis SM, Carageorgiou HC, Varonos DD, and Cokkinos DV

Subjects
Animals, Cardiomegaly metabolism, Chronic Disease, Electrophoresis, Polyacrylamide Gel, HSP70 Heat-Shock Proteins genetics, Hyperthyroidism drug therapy, Hyperthyroidism metabolism, Immunoblotting, Male, Mitogen-Activated Protein Kinases analysis, Myocardial Ischemia metabolism, Perfusion, Phosphorylation, Protein Kinase C analysis, Protein Kinase C metabolism, RNA, Messenger analysis, Rats, Rats, Wistar, Statistics, Nonparametric, Thyroxine blood, Triiodothyronine blood, p38 Mitogen-Activated Protein Kinases, HSP70 Heat-Shock Proteins metabolism, Hyperthyroidism complications, Mitogen-Activated Protein Kinases metabolism, Myocardial Ischemia complications, Myocardium metabolism, Thyroxine therapeutic use
Abstract

The present study was undertaken to investigate heat stress protein (HSP)-70 mRNA induction and p38 MAP kinase (MAPK) activity in response to ischaemic stress in the hyperthyroid rat heart. L-Thyroxine (T(4)) (25 microg/100 g body weight) was administered to Wistar rats for 2 days (THYRacute) or 14 days (THYR), while animals treated similarly with normal saline served as controls (NORMacute and NORM). In addition, abdominal aortic banding was performed in another group of rats to produce constriction-induced hypertrophy (HYP), while sham-operated (SOP) animals served as controls. Isolated rat hearts were perfused in a Langendorff mode. Hearts from NORMacute (n=6), THYRacute animals (n=8), NORM (n=6), THYR (n=6), SOP (n=5) and HYP (n=7) animals were subjected to 20 min of zero-flow global ischaemia followed by 45 min of reperfusion. HSP70 mRNA expression and phosphorylated p38 MAPK protein expression were detected in response to ischaemia and protein kinase C-epsilon (PKCepsilon) protein expression was detected at baseline. Thyroid hormones were measured in plasma. Long-term T(4) administration and aortic constriction resulted in the development of cardiac hypertrophy. Thyroid hormones were increased in both THYR and THYRacute as compared with normal groups (P<0.05). HSP70 mRNA induction was increased 2.3-fold in THYR as compared with NORM hearts (P<0.05), whereas there was not any difference between THYRacute and NORMacute hearts (P>0.05). Phosphorylated p38 MAPK protein expression was 2.2-fold more in NORM than in THYR hearts (P<0.05), but it was not different between NORMacute and THYRacute hearts (P>0.05). HSP70 mRNA induction was 1.8-fold greater in HYP than in SOP hearts (P<0.05), whereas phosphorylated p38 MAPK protein expression was similar between the two groups (P>0.05). PKCepsilon protein expression at baseline was 1.7-fold more in NORM than in THYR hearts (P<0.05), and not different between NORMacute and THYRacute hearts (P>0.05) as well as HYP and SOP hearts (P>0.05). This study shows that HSP70 mRNA expression is increased, whereas p38 MAPK activation is attenuated in response to ischaemia in long-term T(4)-treated rat hearts as compared with normal and acute hyperthyroid hearts.

Published
2001
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2. Phenylephrine induced aortic vasoconstriction is attenuated in hyperthyroid rats

Author

Ci, Pantos, Tzilalis V, Giannakakis S, Dd, Cokkinos, Sm, Tzeis, Malliopoulou V, Iordanis Mourouzis, Asimakopoulos P, Carageorgiou H, Dd, Varonos, and Dv, Cokkinos

Subjects
Male, Vasodilator Agents, Aorta, Thoracic, Cardiomegaly, Hyperthyroidism, Myocardial Contraction, Acetylcholine, Muscle, Smooth, Vascular, Potassium Chloride, Rats, Phenylephrine, Thyroxine, Vasoconstriction, Models, Animal, Animals, Vasoconstrictor Agents, Endothelium, Vascular, Rats, Wistar
Abstract

Abnormal vascular responsiveness to vasoconstrictors may play an important role in peripheral vascular resistance in hyperthyroidism. The aim of the present study was to evaluate whether the vascular response to potassium chloride and phenylephrine is abnormal in a rat model of thyroxine-induced cardiac hypertrophy.Left ventricular hypertrophy was induced in Wistar rats by subcutaneous administration of L-thyroxine for two weeks ("THYR"), n=17. Animals treated with normal saline served as controls, ("NORM"), n=20. The thoracic aorta was dissected and cut into rings that were suspended in an isolated organ bath with Krebs-Henseleit buffer. Maximal tension, Tmax, in g was measured in response to KCl and PE at the highest concentration in rings with endothelium (+E) and without endothelium (-E) in both groups. Relaxation response (Relax percent) to acetylcholine administration was expressed as percent of the maximal tension induced by phenylephrine.Left ventricular weight was 0.9 (SEM, 0.04) g for THYR group vs 0.7 (0.02) g for the NORM group, p0.05. With KCl, Tmax was not different between the THYR and NORM groups with and without endothelium. With PE, there was a difference in Tmax between THYR+E and NORM+E, 1.2 (0.05) g vs 1.5 (0.09) g, p0.05. Tmax was also different between THYR-E and NORM-E, 1.5 (0.08) g vs 1.7 (0.07) g, p0.05. Relax percent was not significantly different between THYR+E and NORM+E (45.9 percent vs 42.8 percent, p0.05).We conclude that: a) Vascular tension of the thoracic aorta in response to PE is lower in thyroxine-treated rats as compared to controls, probably due to enhanced PE-induced vasorelaxation at high concentration. b) Relaxation response of the thoracic aorta to acetylcholine is not different between THYR and NORM groups.

Published
2001

3. Pharmacological inhibition of TRα1 receptor potentiates the thyroxine effect on body weight reduction in rats: potential therapeutic implications in controlling body weight.

Author

Pantos, C., Mourouzis, I., Paizis, I., Malliopoulou, V., Xinaris, Ch., Moraitis, P., Cokkinos, A. D., and Cokkinos, D. V.

Subjects
THYROID hormones, AMIODARONE, HEART beat, WEIGHT gain, BODY size, LABORATORY rats
Abstract

It has been previously reported that thyroid hormone receptor α1 (TRα1) is involved in the regulation of food intake and heart rhythm. Herein, we show that pharmacological inhibition of TRα1 by dronedarone, an amiodarone like compound (shown to antagonize thyroid hormone binding to TRα1), prevented the thyroid hormone induced increase in food intake and heart rate acceleration in rats. This resulted in a marked reduction in body weight. It is likely that thyroid analogs may prove potential therapeutic agents for controlling body weight. [ABSTRACT FROM AUTHOR]

Published
2007
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4. 580 Long-term thyroxine administration results in heat shock protein 27 (HSP27) overexpression and protects the heart from ischaemia

Author

Pantos, C., Malliopoulou, V., Mourouzis, I., Karamanoli, E., Moraitis, P., Tzeis, S., Karageorgiou, H., Varonos, D.D., and Cokkinos, D.V.

Subjects
*THYROXINE, *HEAT shock proteins
Abstract

An abstract of the study "Long-term Thyroxine Administration Results in Heat Shock Protein 27 (HSP27) Overexpression and Protects the Heart From Ischaemia," by C. Pantos and colleagues is presented.

Published
2004

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