Claudia Kiermayer, Bernhard Michalke, Jrg Schmidt, Markus Brielmeier
Effect of selenium on thioredoxin reductase activity in Txnrd1 or Txnrd2 hemizygous mice
Thioredoxin reductase 1 (Txnrd1) and Thioredoxin reductase 2 (Txnrd2) are
selenoproteins whose expression and function depends on adequate supply with
the trace element selenium (Se). As homozygous (-/-) knock out of both Txnrd1 and
Txnrd2 is embryonically lethal, we investigated the effect of their hemizygosity (+/-)
alone and in combination with dietary Se on the enzymatic activity in various tissues.
Additionally, in order to asses overall health of the corresponding mice, growth,
viability and fertility of the different experimental groups was compared. Se depletion
led to a marked reduction in Se organ contents. Se depletion was most prominent
in lung, followed by liver, kidney, heart, muscle and brain. We found no major effect
of Txnrd1 or Txnrd2 hemizygosity and/or Se on male fertility and the viability of the
offspring. A gene dose effect under Se-adequate conditions for Txnrd1 and Txnrd2 in
all organs was observed. Haploid insufficiency decreased Txnrd activity to an extent
that can be further decreased by Se deficiency; however, not to levels below those
which were reached by Se depletion alone. The only exception is the Txnrd2 activity in
kidney, heart and muscle where we found an additive effect.
Biological Chemistry, Walter de Gruyter
Print ISSN: 1431-6730
Volume: 2007
Pages: -
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