Changes of lipoamide dehydrogenase and mitochondrial structure in selenium-deficient chicks.

A selenium deficiency in chicks produces degeneration and fibrosis of the pancreas. An investigation was undertaken to determine whether or not the activity of lipoic acid is impaired in the pancreas of selenium-deficient chicks. Enzymatic analyses of selenium-deficient chick tissues showed a reduction in lipoamide dehydrogenase both in pancreas and liver at a very early stage of growth. Using both direct measurements and sucrose-gradient cellular fractionation, it was found that the lipoamide dehydrogenase activity of the supernatant increased, and that of the mitochondria decreased in selenium-deficient as compared to normal chick livers. These results indicate an increased fragility of the mitochondrial membranes in selenium-deficient chicks.