ABSTRACT
Introduction 441
Selenium Metabolism 442
Symptoms of Dietary Selenium Deficiency 443
Regulation of Selenoprotein Expression 444
Dietary Selenium and Selenoprotein Expression 447
Dietary Selenium and Differential Gene Expression 449
References 452
INTRODUCTION
The element selenium (Se34) was discovered in 1817 by the Swedish chemist
Jacob J. Berzelius. Historically, selenium was regarded as a naturally occurring
toxic agent, but this perspective has undergone a radical transformation in the
past 50 years. In 1973, it was established that selenium is an essential micronu-
trient in mammals (1,2). It exerts a number of important health benefits including
protection against oxidative stress, cancer, AIDS, inflammatory diseases, and
male infertility. On the molecular level, selenium shows extraordinary behavior,
as it is incorporated into proteins as selenocysteine, for which the UGA codon is
transformed from one that signals translation termination to one specific for
selenocysteine.
