How TNF and IL-1 Affect Muscle Breakdown
Author Information
Author(s): Oded Zamir, Per-Olof Hasselgren, Takashi Higashiguchi, Janice A. Frederick, Josef E. Fischer
Primary Institution: University of Cincinnati Medical Centre
Hypothesis
Muscle proteolysis induced by TNF or IL-1 is mediated by glucocorticoids.
Conclusion
The study found that TNF-induced muscle protein breakdown is mediated by glucocorticoids, while IL-1 stimulates muscle proteolysis through a different mechanism.
Supporting Evidence
- Total protein breakdown rate increased by 46% after IL-1 administration.
- Myofibrillar protein breakdown rate increased more than two-fold after IL-1 administration.
- TNF-induced muscle proteolysis was completely blocked by the glucocorticoid receptor antagonist RU 38486.
- Plasma corticosterone levels increased after administration of both IL-1 and TNF.
Takeaway
This study shows that a substance called TNF makes muscles break down proteins, but it needs help from another substance called glucocorticoids, while IL-1 can do it on its own.
Methodology
Rats were treated with cytokines and a glucocorticoid receptor blocker, and muscle protein breakdown rates were measured.
Limitations
The study did not measure muscle protein synthesis.
Participant Demographics
Male Sprague-Dawley rats weighing 40-60 g.
Statistical Information
P-Value
p<0.05
Statistical Significance
p<0.05
Want to read the original?
Access the complete publication on the publisher's website