Evaluation of the effects of the dietary intake of proteins and amino acids by DNA microarray technology

The DNA microarray technique has been increasingly utilized in various fields of life sciences. It allows us to analyze the expression levels of thousands of genes simultaneously. The high productivity will facilitate the evaluation of changes in amino acid metabolism and their consequences in response to dietary proteins and amino acids. We compared the expression profiles by the GeneChip system in the liver and other tissues among three groups of rats fed with a 12% casein, a 12% gluten or a protein-free diet. Feeding the gluten or the protein-free diet up- or down-regulated a few hundred genes in the liver compared to the casein diet. Although some of the genes were already known to respond to changes in the protein nutritional state, the majority was newly identified responders. This paper also discusses the possibility of a use this technology for safety evaluation of excessive intake of dietary components, especially of amino acids.