The effect of hypothyroid state on the transmembrane potential was studied in isolated cardiac ventricular trabeculae of rats. Hypothyroid state was induced by methimazole treatment or thyroidectomy and checked by determining serum thyroxine level. Hypothyroidism decreased the maximum rate of depolarization (Vmax) and the resting potential, increased the overshoot and the duration of action potential at 20, 50 and 90% repolarization. These changes were more pronounced after methimazole treatment than after thyroidectomy. The results strongly suggest that in hypothyroidism the significant alterations in the voltage-time course of the transmembrane action potential influencing Ca2+-movement across the sarcolemma may have an indirect role in the decreased myocardial contractility. On the other hand, methimazole has an aspecific cardiac effect which may modify the cardiac effect of hypothyroidism induced by the drug.
Download full-text PDF |
Source |
|---|
Publication Analysis
Top Keywords
Similar Publications
Effect of a Low-Molecular-Weight Allosteric Agonist of the Thyroid-Stimulating Hormone Receptor on Basal and Thyroliberin-Stimulated Activity of Thyroid System in Diabetic Rats.
Int J Mol Sci
January 2025
Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg 194223, Russia.
The approaches to correct thyroid deficiency include replacement therapy with thyroid hormones (THs), but such therapy causes a number of side effects. A possible alternative is thyroid-stimulating hormone (TSH) receptor activators, including allosteric agonists. The aim of this work was to study the effect of ethyl-2-(4-(4-(5-amino-6-(-butylcarbamoyl)-2-(methylthio)thieno[2,3-d]pyrimidin-4-yl)phenyl)--1,2,3-triazol-1-yl) acetate (TPY3m), a TSH receptor allosteric agonist developed by us, on basal and thyroliberin (TRH)-stimulated TH levels and the hypothalamic-pituitary-thyroid (HPT) axis in male rats with high-fat diet/low-dose streptozotocin-induced type 2 diabetes mellitus (T2DM).
View Article and Find Full Text PDFHypothyroidism Alters Uterine Kisspeptin System and Activity Modulators in Cyclic Rats.
Int J Mol Sci
January 2025
Electron Microscopy Center, Department of Biological Sciences, State University of Santa Cruz, Ilheus 45662-900, Brazil.
Hypothyroidism causes ovarian dysfunction and infertility in women and animals and impairs the hypothalamic expression of kisspeptin (Kp). However, kisspeptin is also expressed in the genital system, and the lack of the Kp receptor (Kiss1r) in the uterus is linked to reduced implantation rates. This study investigated the impact of hypothyroidism on the uterine expression of Kp and Kiss1r in female rats throughout the estrous cycle and the associated changes in uterine activity modulators.
View Article and Find Full Text PDFBackground: Hypothyroidism is a common sequela after radiotherapy for nasopharyngeal carcinoma (NPC). Magnetic resonance imaging (MRI) has gained prominence in thyroid imaging, leveraging its non-ionizing radiation, high spatial resolution, multiparameter and multidirectional imaging. Few previous studies have investigated the evaluation of radiation-induced thyroid injury by MRI.
View Article and Find Full Text PDFParent Reports of Developmental Service Utilization After Newborn Screening.
Int J Neonatal Screen
December 2024
RTI International, 3040 E. Cornwallis Road, Research Triangle Park, P.O. Box 12194, Research Triangle Park, NC 27709, USA.
Newborn screening (NBS) presents an opportunity to identify a subset of babies at birth who are at risk for developmental delays and could benefit from a range of developmental services. Potential developmental services in the United States include Part C Early Intervention (EI), private therapies, and school-based services. Using parent-reported outcomes, this study examined the rates at which a sample of children diagnosed with NBS conditions used each developmental service.
View Article and Find Full Text PDFGenetic insights and therapeutic avenues: unraveling the role of polyunsaturated fatty acids as mediators between hypothyroidism and Von Willebrand disease through Mendelian randomization.
Front Genet
January 2025
Department of Neurology, West China Hospital, Sichuan University, Chengdu, China.
Background: Previous observational studies have shown that Hypothyroidism is associated with Von Willebrand Disease (VWD), but the causal relationship has not been confirmed because of conflicting findings and confounding by mixing factors. There are also some studies suggesting that polyunsaturated fatty acids (PUFA) may be one of the potential mediators. In this study, we used a Mendelian randomization study to analyze the causal relationship between Hypothyroidism and VWD and to investigate whether polyunsaturated fatty acids mediate the effects of Hypothyroidism on VWD.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!