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Thyroid hormone induced changes in cardiac proteins and mRNAs
W H Dillmann1, D Rohrer, B Popovich
1Dept. of Medicine, University of California, San Diego.
Hormone and Metabolic Research. Supplement Series
|January 1, 1987
Summary
Thyroid hormone significantly impacts heart function by altering specific messenger RNA (mRNA) levels. This study reveals how thyroid hormone influences Ca++ ATPase and myosin heavy chain (MHC) mRNA, explaining hypothyroid heart conditions.
Area of Science:
- Cardiology
- Molecular Biology
- Endocrinology
Background:
- Hypothyroid heart contraction shows delayed relaxation and reduced systolic velocity.
- Alterations in sarcoplasmic reticulum Ca++ ATPase and myosin heavy chain (MHC) alpha/beta mRNA are suspected contributors.
Purpose of the Study:
- To quantify Ca++ ATPase and MHC alpha/beta mRNA levels in hypothyroid hearts.
- To investigate the effect of thyroid hormone (T3) administration on these mRNA levels.
Main Methods:
- Northern blotting technique was used to measure specific mRNA levels.
- Hypothyroid rats were administered T3 to observe changes over time.
Main Results:
- Ca++ ATPase mRNA was 3-fold lower in hypothyroid hearts, normalizing post-T3 administration.
- MHC beta mRNA predominated in hypothyroid hearts, while MHC alpha mRNA was low.
- T3 administration rapidly increased MHC alpha mRNA levels, normalizing within 24 hours.
Conclusions:
- Thyroid hormone significantly alters mRNA levels for Ca++ ATPase and MHC alpha/beta.
- These mRNA changes likely explain the impaired relaxation and contraction velocity in hypothyroid hearts.