Effects of selenium on liver and muscle contents and urinary excretion of zinc, copper, iron and manganese.

Selenium is a main component of glutathione peroxidase (GPX), a key antioxidant enzyme. Other elements, such as zinc, copper, manganese and iron, are also involved in the pathogenesis of oxidative damage as well as in other important metabolic pathways. The effects of selenium supplementation on the metabolism of these elements have yield controversial results .

Alcoholic myopathy: lack of effect of zinc supplementation.

A chronic form of myopathy has been described in alcoholics, characterized by atrophy of type II fibers, due both to reduced protein synthesis and increased protein breakdown. Increased production of reactive oxygen species could probably play a role in increased protein breakdown. In addition, treatment with zinc might be beneficial, since it acts as a cofactor of several enzymes involved in the synthesis of proteins and antioxidants as copper-zinc-superoxidedismutase (SOD) and selenium dependent glutathione peroxidase (GPX).

Combined effects of steroids, ethanol and protein deficiency on tissue content and urinary and faecal excretion of zinc, copper and iron.

This study was performed in order to determine the relative and combined effects of ethanol, a low protein diet and steroid treatment on bone, muscle, liver, and urinary and faecal excretion of zinc, copper and iron in 64 rats divided into eight groups treated following the Lieber-DeCarli liquid diet technique, with and without dexamethasone, 1 mg/l. Steroids showed a lack of effect on liver zinc, but enhanced ethanol- and low protein-mediated liver iron overload when both factors were combined. Steroids also increased muscle copper, iron and zinc, and bone copper, especially in the low protein, ethanol-fed rats.