Related Experiment Videos
Fasting decreases triiodothyronine receptor capacity
Science (New York, N.Y.)
|February 10, 1978
Summary
Fasting reduces thyroid hormone triiodothyronine (T3) by decreasing T3 receptors in liver cells. This adaptation conserves energy during fasting, protecting cells with low reserves.
Area of Science:
- Endocrinology
- Cellular Metabolism
- Molecular Biology
Background:
- Fasting triggers significant metabolic adaptations to conserve energy.
- Thyroid hormones, particularly triiodothyronine (T3), play a crucial role in regulating metabolism.
- Hepatic nuclear T3 receptors are key mediators of T3 action in the liver.
Purpose of the Study:
- To investigate the impact of fasting on hepatic nuclear T3 receptor binding capacity.
- To elucidate the relationship between serum T3 levels and nuclear T3 receptor content during fasting.
- To understand the cellular mechanisms underlying metabolic adaptation to fasting.
Main Methods:
- Measurement of serum T3 concentrations in fasted and control animals.
- Assessment of nuclear T3 receptor binding capacity in liver tissue.
- Quantification of nuclear T3-receptor complexes.
Main Results:
- Fasting significantly decreased the ratio of hepatic nuclear to serum triiodothyronine (T3).
- This decrease was primarily due to diminished binding capacity of nuclear T3 receptors.
- Fasting led to a marked reduction in nuclear T3-receptor complexes, independent of whole-animal metabolic status.
Conclusions:
- Fasting induces a coordinated decrease in both circulating T3 and hepatic nuclear T3 receptor content.
- These changes represent synergistic adaptations for caloric conservation during the fasted state.
- Modulation of nuclear receptor content offers a cell-autonomous protective mechanism for energy reserves.