1. Thyroid hormone regulates Ca(2+)-ATPase mRNA levels of sarcoplasmic reticulum during neonatal development of fast skeletal muscle.
- Author
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van der Linden GC, Simonides WS, and van Hardeveld C
- Subjects
- Animals, Calcium-Transporting ATPases genetics, Enzyme Induction drug effects, Female, Hypothyroidism metabolism, Isoenzymes genetics, Muscle Development, Muscle Proteins genetics, Pregnancy, Rats, Rats, Wistar, Sarcoplasmic Reticulum drug effects, Triiodothyronine pharmacology, Animals, Newborn metabolism, Calcium-Transporting ATPases biosynthesis, Isoenzymes biosynthesis, Muscle Proteins biosynthesis, Muscles enzymology, RNA, Messenger biosynthesis, Sarcoplasmic Reticulum enzymology, Thyroid Hormones physiology
- Abstract
In gastrocnemius muscle from newborn rats the mRNA for the fast sarcoplasmic reticulum (SR) Ca(2+)-ATPase isoform (SERCA1) comprised over 90% of total SR Ca(2+)-ATPase mRNA content and increased 5-fold between day 5 and 20 after birth, whereas in hypothyroid muscle the SERCA1 message level remained constant. Triiodothyronine (T3) treatment of 2-day-old euthyroid rats induced a precocious stimulation of SERCA1 mRNA levels, indicating that T3 is the determining factor in the stimulation of SERCA1 message levels and that this stimulation underlies the previously reported effect of the thyroid status on the neonatal development of SR Ca(2+)-ATPase activity. The low mRNA level for the slow SR Ca(2+)-ATPase isoform (SERCA2) was constant in both euthyroid and hypothyroid muscle development. Nevertheless, T3 treatment of hypothyroid neonates induced a transient stimulation of SERCA2 message levels, indicating that SERCA2 is responsive to higher levels of T3.
- Published
- 1992
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