Related Experiment Videos
Physiological role of thiol proteases in thyroid hormone secretion
Acta Endocrinologica
|October 1, 1986
Summary
Thiol proteases are crucial for thyroid hormone release from thyroglobulin. Leupeptin, a thiol protease inhibitor, blocks thyroid-stimulating hormone
Area of Science:
- Endocrinology
- Molecular Biology
- Cell Biology
Background:
- Thyroid hormones (T4 and T3) are synthesized and stored within thyroglobulin.
- The release of thyroid hormones involves the proteolytic degradation of thyroglobulin.
Purpose of the Study:
- To elucidate the physiological role of thiol proteases in T4 and T3 release.
- To investigate the mechanism by which leupeptin affects thyroid hormone secretion.
Main Methods:
- In vitro incubation of 131I-prelabelled rat thyroid lobes.
- Treatment with bovine TSH and leupeptin (a thiol protease inhibitor).
- Analysis of lysosomal proteolytic activity and thyroglobulin degradation.
Main Results:
- TSH significantly stimulated T4 and T3 secretion, an effect abolished by leupeptin.
- Leupeptin inhibited lysosomal proteolytic activity and intralysosomal hydrolysis of thyroglobulin.
- Leupeptin prevented the degradation of 19S thyroglobulin and formation of smaller peptides.
Conclusions:
- Thiol proteases play a key role in TSH-stimulated thyroid hormone release.
- Leupeptin's inhibition of thyroid hormone secretion is mediated by blocking thyroglobulin proteolysis.
- Lysosomal thiol proteases are essential for the efficient release of T4 and T3.