title: Expression of a thioredoxin peroxidase in insulin-producing cells.
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.
authors.affiliation: Department of Physiology and Biophysics, Institute of Biology, State University of Campinas, SP, Brazil. boschero@unicamp.br
authors.forename: A C
authors.initials: AC
authors.lastname: Boschero
authors.forename: L F
authors.initials: LF
authors.lastname: Stoppiglia
authors.forename: C B
authors.initials: CB
authors.lastname: Collares-Buzato
authors.forename: J R
authors.initials: JR
authors.lastname: Bosqueiro
authors.forename: V
authors.initials: V
authors.lastname: Delghingaro-Augusto
authors.forename: A
authors.initials: A
authors.lastname: Leite
authors.forename: C P F
authors.initials: CP
authors.lastname: Carvalho
authors.forename: L E S
authors.initials: LE
authors.lastname: Netto
authors.forename: E M
authors.initials: EM
authors.lastname: Carneiro
mesh_terms: 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
chemical_list: D009363:Neoplasm Proteins; D010544:Peroxidases; D054464:Peroxiredoxins