Thyroid control of sarcolemmal Na+/Ca2+ exchanger and SR Ca2+-ATPase in developing rat heart
Language English Country United States Media print
Document type Journal Article, Research Support, Non-U.S. Gov't
- MeSH
- Calcium-Transporting ATPases biosynthesis MeSH
- Transcription, Genetic drug effects MeSH
- Hyperthyroidism chemically induced metabolism physiopathology MeSH
- Hypothyroidism chemically induced metabolism physiopathology MeSH
- Rats MeSH
- Membrane Proteins metabolism MeSH
- RNA, Messenger biosynthesis MeSH
- Myocardium metabolism MeSH
- Animals, Newborn MeSH
- Rats, Wistar MeSH
- Propylthiouracil pharmacology MeSH
- Calcium-Binding Proteins biosynthesis MeSH
- Sodium-Calcium Exchanger biosynthesis MeSH
- Regression Analysis MeSH
- Sarcolemma metabolism MeSH
- Sarcoplasmic Reticulum enzymology MeSH
- Heart growth & development MeSH
- Thyroid Gland physiology MeSH
- Triiodothyronine pharmacology MeSH
- Gene Expression Regulation, Developmental * drug effects MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Calcium-Transporting ATPases MeSH
- Membrane Proteins MeSH
- RNA, Messenger MeSH
- phospholamban MeSH Browser
- Propylthiouracil MeSH
- Calcium-Binding Proteins MeSH
- Sodium-Calcium Exchanger MeSH
- Triiodothyronine MeSH
Thyroid hormone (TH) levels increase in the postnatal life and are essential for maturation of myocardial Ca2+ handling. During this time, the sarcolemmal (SL) Na+/Ca2+ exchanger (NCX) function decreases and the sarcoendoplasmic reticulum (SR) Ca2+-ATPase (SERCA2) function increases. We examined the effects of postnatal hypo- or hyperthyroidism on NCX and SERCA2 in rat hearts. Animals were rendered hypothyroid by 0.05% 6-n-propyl-2-thiouracil in drinking water given to nursing mothers from days 2 to 21 postpartum. Hyperthyroidism was induced by daily injections of 10 microg/100 g body weight of 3,3',5-triiodo-L-thyronine during this period. Ventricular steady-state mRNA and protein levels of NCX and SERCA2 were analyzed by Northern and Western blotting. These were compared with SL Na+ gradient-induced and SR oxalate-supported Ca2+ transports in isolated membranes. In hypothyroidism, NCX mRNA and protein were elevated by 66 and 80%, respectively, and SERCA2 mRNA and protein were reduced to 55 and 70%, respectively (P < 0.05 vs. euthyroid). Corresponding differences were observed in the respective Ca2+ transports. Conversely, reduced NCX (by 50%) and elevated SERCA2 (by 150%) activities were found in hyperthyroidism (P < 0.05). The levels of NCX and SERCA2 mRNA and protein were, however, unchanged in hyperthyroidism, indicating that functional changes are not due to altered NCX and SERCA2 expression. In this case, a decline in noninhibitory phosphorylated phospholamban is a likely explanation for the elevated SR Ca2+ transport. In conclusion, physiological TH levels appear to be essential for normal reciprocal changes in the expression and function of myocardial NCX and SERCA2 during postnatal development.
References provided by Crossref.org
Sixty Years of Heart Research in the Institute of Physiology of the Czech Academy of Sciences
Effect of hypo- and hyperthyroid states on phospholipid composition in developing rat heart
