1. Expression of a thioredoxin peroxidase in insulin-producing cells.
- Author
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Boschero AC, Stoppiglia LF, Collares-Buzato CB, Bosqueiro JR, Delghingaro-Augusto V, Leite A, Carvalho CP, Netto LE, and Carneiro EM
- Subjects
- Aging, Animals, Animals, Newborn, Cells, Cultured, Insulinoma, Islets of Langerhans cytology, Islets of Langerhans growth & development, Oxidative Stress physiology, Pancreatic Neoplasms, Peroxiredoxins, Rats, Rats, Wistar, Tumor Cells, Cultured, Islets of Langerhans enzymology, Neoplasm Proteins, Peroxidases metabolism
- Abstract
The presence of thioredoxin peroxidase (TPx), also known as thiol specific antioxidant (TSA), was investigated in neonatal and adult rat islets, and in the beta-cell line HIT-T15. Western blotting of extracts from neonatal and adult pancreatic islets and from the tumoral cell line HIT-T15 revealed the presence of a 25 kDa protein that comigrated with purified yeast TPx. Endocrine pancreatic TPx accounted for approximately 0.01% of the total protein content. Treatment with H2O2 for 3 h increased the expression of TPx in HIT-T15 cells. The distribution of TPx throughout the islet cells was confirmed by immunocytochemistry. Since pancreatic beta-cells possess a weak antioxidant enzyme defense system, especially with regard to hydrogen peroxidase-decomposing enzymes, the presence of a TPx analog in islets suggests that this enzyme may play a role in protecting pancreatic cells against reactive oxygen species.
- Published
- 2002