Hemolysate thioredoxin reductase and glutathione peroxidase activities correlate with serum selenium in a group of New Zealand men at high prostate cancer risk.

The study provides data relating serum selenium concentration to activities of 2 key selenoenzymes, hemolysate thioredoxin reductase (TR) and glutathione peroxidase (GPx), measured by spectrophotometry, in a group of men at high risk for prostate cancer. This trial enrolled 43 patients with elevated prostate-specific antigen but negative biopsy for prostate cancer. Such individuals have a high risk of developing prostate cancer in the succeeding 5 y. In the men with baseline serum selenium concentrations ranging from 0.74-1.62 micromol/L (59-128 microg/L), hemolysate TR (r = 0.359, P < 0.05) and GPx (r = 0.341, P < 0.05) activities increased with increasing serum selenium. Furthermore, after a run-in period of 1 mo, men participated in a randomized, double-blind, placebo-controlled selenium supplementation trial for 6 mo and received a placebo, or 200 or 400 microg of Se per day, in the form of a seleno yeast. This study is a subsidiary of an ongoing Phase III cancer chemoprevention trial and, as such, randomization groups have not yet been revealed. After 6 mo of being on trial and with an estimated 66% of the group being supplemented with seleno yeast, the TR activity of the group increased by 80% relative to baseline. In contrast, 6 mo of selenium supplementation did not affect GPx activity. This study presents, to our knowledge for the first time, both measurements of human hemolysate TR activity and its relation to serum selenium.

RCT Entities:   Population Interventions Outcomes