What question did this study set out to answer?

To determine how thyroid hormone (T3) and insulin regulate cardiac myosin heavy chain (MHC) alpha and beta mRNAs and other transcripts in the rat heart.

January 1, 1989Endocrine Research

Influence of Thyroid Hormone on Myosin Heavy Chain mRNA and Other Messenger RNAs in the Rat Heart

Q: What is the clinical evidence from this study?

Study design: Other. Population: Hypothyroidism and diabetes (rat model). Intervention: T3 (thyroid hormone) and insulin vs. Untreated hypothyroid/diabetic baseline. Primary outcome: Myosin heavy chain (MHC) alpha mRNA levels.

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Key result

Administration of T3 to hypothyroid rats restored MHC-alpha mRNA to control levels by 24 hours, while insulin in diabetic rats caused a significant increase within 30 minutes.

Population

Hypothyroid and diabetic rat models

Comparison

0.2 mg T3/100 g body wt. or 2 units regular… vs Untreated hypothyroid and diabetic rats, and…

Design

Preclinical

Follow-up

Up to 24 hours

Authors

WDWolfgang DillmannGeneral Cardiology ABA BarrieuxInserm RSRavi ShankerUniversity of Allahabad

Discussion

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Implication

Thyroid hormone may shift cardiac MHC isoforms in metabolic stress; leaves open relevance to human cardiomyopathy.

Key Points

To determine how thyroid hormone (T3) and insulin regulate cardiac myosin heavy chain (MHC) alpha and beta mRNAs and other transcripts in the rat heart.
Quantitated cardiac MHC-alpha and MHC-beta mRNA in normal, hypothyroid, and diabetic rats using a specific cDNA probe.
Administered 0.2 mg T3 per 100 g body weight to hypothyroid rats and 2 units of insulin to diabetic rats, evaluating mRNA levels at time points up to 24 hours.
Profiled additional T3-responsive cardiac mRNAs using in vitro translation, 35S-methionine labeling, and digital matrix photometry.
Normal hearts expressed 80% MHC-alpha mRNA, whereas hypothyroid and diabetic hearts predominantly expressed MHC-beta mRNA.
T3 administration in hypothyroid rats induced an increase in MHC-alpha mRNA beginning at 3 hours and reaching normal control levels by 24 hours; insulin in diabetic rats increased MHC-alpha mRNA by 30 minutes, peaking at 3 hours and returning to baseline by 5 hours.
A cardiac mRNA transcript (spot 72b, Mr 81,000 and pI 5.4) increased 3-fold within 1 hour of T3 administration, demonstrating more rapid induction than MHC-alpha mRNA.

Structured PICO

Population

Hypothyroid and diabetic rats evaluated for cardiac myosin heavy chain mRNA levels.

Intervention

0.2 mg T3/100 g body wt. (hypothyroid rats) or 2 units regular insulin (diabetic rats)

Comparator

Untreated hypothyroid and diabetic rats, and normal rat hearts

Outcome

Myosin heavy chain (MHC) alpha and beta mRNA levelssurrogate

Thyroid hormone and insulin rapidly modulate myosin heavy chain mRNA expression in the rat heart, highlighting dynamic transcriptional or post-transcriptional regulation.

Limitations

It is currently unclear if the T3 response of MHC-alpha mRNA represents a primary effect of T3.

Cite This Study

Dillmann et al. (1989) studied Hypothyroidism and diabetes (rat model). T3 (thyroid hormone) and insulin vs. Untreated hypothyroid/diabetic baseline was evaluated on Myosin heavy chain (MHC) alpha mRNA levels. Administration of T3 to hypothyroid rats restored MHC-alpha mRNA to control levels by 24 hours, while insulin in diabetic rats caused a significant increase within 30 minutes.

synapsesocial.com/papers/6a6542ef1b122b07e7b2e32e https://doi.org/10.3109/07435808909036352

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Influence of Thyroid Hormone on Myosin Heavy Chain mRNA and Other Messenger RNAs in the Rat Heart

Discussion

Member takes

Implication

Key Points

Structured PICO

Limitations

Cite This Study

Influence of Thyroid Hormone on Myosin Heavy Chain mRNA and Other Messenger RNAs in the Rat Heart

Discussion

Member takes

Implication

Key Points

Structured PICO

Limitations

Cite This Study

Also Consider

Also Consider