Enough liver tissue (approximately 1-2 mg) will be obtained to isolate messenger RNA (mRNA) by oligo dT chromatography. Once isolated the mRNA will be reverse transcribed to complementary DNA (cDNA). This cDNA will then be labeled with a fluorescent reporter molecule. Hybridization of the labeled liver cDNA will then occur with the DNA microarray. It is envisaged that the microarray will be commercially obtained and consist of human cDNA. There is enough DNA on the microarray that two lots of labeled liver cDNA with different fluorescent markers (i.e. red and green) can be hybridized to the array at the same time without any interference. The following hybridizations would then be set up.