Expression of a thioredoxin peroxidase in insulin-producing cells.
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.
Boschero
A C
AC
Department of Physiology and Biophysics, Institute of Biology, State University of Campinas, SP, Brazil. boschero@unicamp.br
Stoppiglia
L F
LF
Collares-Buzato
C B
CB
Bosqueiro
J R
JR
Delghingaro-Augusto
V
V
Leite
A
A
Carvalho
C P F
CP
Netto
L E S
LE
Carneiro
E M
EM
D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D007340:Insulinoma; D007515:Islets of Langerhans / Q000166:cytology / Q000201:enzymology* / Q000254:growth & development; D009363:Neoplasm Proteins; D018384:Oxidative Stress / Q000502:physiology; D010190:Pancreatic Neoplasms; D010544:Peroxidases / Q000378:metabolism*; D054464:Peroxiredoxins; D051381:Rats; D017208:Rats, Wistar; D014407:Tumor Cells, Cultured
D009363:Neoplasm Proteins; D010544:Peroxidases; D054464:Peroxiredoxins